Difference between revisions of "Custom Reports"

Latest revision as of 23:26, 24 October 2023

This documentation applies from GnuCash Version 5.0. For prior versons use the previous version.

Custom Reports in GnuCash

The term Custom Reports has several contexts in GnuCash:

Customizing settings for standard reports (Using GnuCash#Saved Report Configurations)
Combining selected standard reports into one view (Using GnuCash#Custom Multicolumn Report)
Customized output format for reports (Custom Reports Using Eguile)
Reports written in the Scheme programming language which are not delivered as part of the standard reports (this page)

If you are not up for coding, you should check the

report options
stylesheets and
stylesheet options and
file properties.

Possibly there are ways to get what you desire without coding.

If you are ready for coding (and even already firm in Scheme and Guile) then this is the place to contribute.

Introduction

Custom reports can be fairly challenging and while the information presented here is brief it should be enough to get you started. The focus is on enough understanding to change (hack) existing reports.

In the GnuCash project the reports are coded in Scheme, not in C. Understanding Scheme is one of the prerequisites to create new reports. The obvious drawback is that one must learn yet another programming language (if not already familiar with it) but saves the effort of having to alter and build GnuCash's source code.

Guile is used as an interface to get the Scheme code executed during runtime. Again, if not already familiar with it, this is the second piece of work that one has to swallow.

Last, but not least, the API for that sort of thing is not formally specified.

Still reading? Not yet discouraged? Good for you! Thankfully, lots of help is available.

First of all, there is good educational material available on the web to help you learn Scheme and Guile. Secondly, there is a simple sample-report.scm example report specifically written to show you the base layout of a GnuCash report. And finally, this Wiki page will give you some guidance when starting this venture.

Getting Started

This tutorial will give you an overview of GnuCash reports and might give you the confidence to make simple changes to existing reports.

Appreciation of Scheme language

GnuCash reports are written in the Scheme programming language. For a quick introduction try Learn Scheme in 15 minutes using an online scheme repl.

Language details

This tutorial is self-contained but to extend it in reports you'll want to use the following references and learn about the language. Just be aware of them for now.

Get to know Scheme

Mastering Scheme is much easier if you've read The Scheme Programming Language by R. Kent Dybvig.

If you are new to Scheme it is not necessary to read and understand all of it right now. For anything more than this tutorial you should, at least, have gone through the Getting Started section.

Get to know Guile

Guile is used internally by GnuCash to interpret the Scheme reports.

Guile documentation

This comes with a marvelous Tutorial. You don't need this for writing the reports themselves, but it gives a clue of how reports are created in GnuCash. This should be good motivation to go and tackle the learning curve for Scheme.

Get to know Gettext

That is the tool which makes the strings translatable. (G_ "Some Text"), (N_ "Some Text") and similar mark the text for translation. See I18N#How to make strings in code translatable for details.

Where to find existing reports

The location of existing reports varies with by operating systems. The guile path can be found in Help -> About -> GNC_DATA by selecting the parent folder.:

Operating System	Path
All Linux except Debian with flatpak including derivatives such as UbuntuBSD	`.../<guile-version>/gnucash/reports`
Debian with flatpak including derivatives such as Ubuntu, OSX bundle (Gnucash.app), Windows	`.../guile/site/2.2/gnucash/reports`

Study some example reports

sample-report

sample-report.scm was created in GnuCash V5.0 from hello-world.scm to demonstrate the basic structure of a report. Don't get too confused by the huge number of options that are shown in this report - they were added to show off the variety of options available in GnuCash.

Have a look under #Where to find existing reports to find the source code for this report. Alternatively, you can browse the current source code for this report on github.

By looking at the result of this report while you study the source code, you will easily get clues to how it functions. You can run this report in GnuCash via the menu: Reports -> Examples -> Sample Report

account-piecharts

If you want to walk through a much more complicated report, study account-piecharts.scm.

There are two long functions in this report.

option-generator defines the options for this report.
piechart-renderer makes all the calculations and renders the pie chart.

The list of values to be shown in the pie chart can be calculated in two ways - depth-based or via a method that traverses all accounts. The decision for this is made when calling the piechart-renderer function. Both methods will work from a list of selected accounts stored in the topl-accounts variable.

traverse-accounts is a recursive function that calls itself to traverse through all child accounts in the account tree. To get the balance for a single account, it makes a call to profit-fn. profit-fn obtains the account balance for either one interval or at a given date. It calls out to gnc:account-get-comm-balance-at-date in report-utilities.scm where, finally, lower level calls are made, which create a query for the account balance at the given date.

Well, long story short, this report is rather involved. Sorry.

Setup a prototype report

Even if you haven't ever written a report before, and you don't have a shiny track record of great Scheme experience, setting up a prototype at this moment will have the benefits getting productive after some time of pure theory.

The beginners amongst us might not have a final picture of what report to write. No worries, take the sample-report.scm report source file, store it in your preferred working directory, and rename it to a unique name, say my-world.scm. As, for sure, you already have read through this report, you know that this report is very wordy, giving a lot of text printouts. These can be used to easily see your own first changes on the screen once this prototype is loaded into GnuCash, and even better, it will let you differentiate between the my-world.scm that you have loaded and the sample-report.scm that is available in GnuCash by default (see previous section). So feel free to implement some fancy printout changes.

Prerequisites

GnuCash will not be able to load your report until you make changes in two areas of your report source file:

Give report a unique symbol name

To avoid symbol definition conflicts with other reports, make sure your report code begins with a define-module statement with a report name not used by any other report, for example:

(define-module (gnucash report my-world-report))

Define report with unique name and id

To enable GnuCash to register your report into the Report menu, scroll to the end of the code and update the gnc:define-report statement.

Set the name of your report to be shown in the Report menu. This name must be unique across all reports.

'name (N_ "My World")

Further down below, if it is present, comment out the menu-name line:

;;'menu-name (N_ "Sample Report with Examples")

Update the tool tip text to something appropriate for your report:

'menu-tip (N_ "Unstable. Used for Testing.")

Your report must have a globally unique identifier (guid). GnuCash will fail to start if multiple reports have the same unique id. For this reason, if you wish to create a backup of a report while you work on it, place the backup outside the GnuCash directories. If you need some newly generated unique id, use an online uuid generator like this one (any other one will do as well). Be sure to untick "Hyphens" to generate gnucash compatible guids. If you forget or the site you use doesn't offer that option, simply remove the hyphens yourself.

Alternatively, in linux, run this construct

uuidgen | sed -e 's/-//g'

^[1]

Copy the newly generated ID and paste it into the report-guid value:

'report-guid "paste generated report unique id here"

Loading Your Report

There are two ways to load a report at startup of GnuCash:

from a user account or
from the installation tree.

You will likely want to use the user account approach - a least until your work is finished.

Load the report from a user account

This method is used if you edit your report source file in a working directory.

Edit GNC_CONFIG_HOME/config-user.scm to add a line of the form:

(load (gnc-build-userdata-path "my-world.scm"))

Notes

(gnc-build-userdata-path ...) or (gnc-build-dotgnucash-path ...) will complement your report name with the full path of your GNC_DATA_HOME or DOT_GNUCASH_DIR directory respectively. If you are comfortable with file locations you could equally well use the form

(load "<absolute path to>/my-world.scm")

to load your report from any arbitrary location on your file system.

The instructions refer to two separate directories: GNC_CONFIG_HOME and GNC_DATA_HOME. Be careful to use the proper one in the different locations as indicated.
If the config.user or config-user.scm file is not yet found in your settings directory, simply create it.

Move, copy, or link* your report file (my-world.scm) from your working directory to the proper GNC_DATA_HOME or DOT_GNUCASH_DIR directory. The report should be visible in the Reports menu after the next restart.

* On Unix-like OSs you can use the ln command; on Windows (7 and higher) you can use the mklink command.

To reload your report, you must restart GnuCash. You will have to do this every time you change a report.

Load the report from the installed report directory

Tip: Despite the warning below, this can be the easiest method in Windows by sandboxing report development with a `Portable Apps version`. Since GnuCash 4.12 the portable `guile` path can be found in `Help -> About -> GNC_DATA` by selecting the parent folder.

While not recommended you can also copy the report to the installed report directory. Make sure you have included a module definition as shown above. All *.scm files from the gnucash/scm/gnucash/report/standard-reports/ directory will be loaded automatically. This applies only to the standard-reports/ sub-directory, not to any of the other directories with reports. Hence, the easiest way to have your report available to gnucash is to copy your *.scm file into that directory.

Note: In case of an eguile based report only the foo.scm file should be stored in the standard-reports directory. The accompanying foo.eguile.scm and foo.css should go in to gnucash/scm/gnucash/report instead.

Then restart GnuCash. You will have to do this every time you change the report definition file.

Debugging your report

When guile cannot make sense of your report, or your report throws an error, GnuCash will present the following error message in place of your report:

Report error An error occurred while running the report.

This lets you know there was a problem, but now you need to pinpoint where the problem lies. Here are some tips that might help.

Tip Details

Enable debug messages

Start GnuCash with debug command line parameters:

gnucash --debug --log gnc.scm=debug

On macOS, assuming GnuCash is in your /Applications folder, this would be:

/Applications/Gnucash.app/Contents/MacOS/Gnucash --debug --log gnc.scm=debug

There are other debug related options, run GnuCash with the --help for a complete list.

Study the trace logs

The GnuCash trace logs can sometimes give you that satisfying "oh, I see". By default you'll find the trace log:

Operating System	Location
Unix/Linux	`$TEMP/gnucash.something.trace`
Windows	`%TEMP%/gnucash.something.trace`
macOS	Somewhere under `/var/folders/` You can find it via: find /var/folders -name "gnucash.trace" 2> /dev/null

You can change the trace log file location via GnuCash command line parameter --logto. This parameter includes support for logging to 'stderr' and 'stdout'

Add your own debug messages

You can use the gnc:debug function to add your own messages. For example:

(gnc:debug "here I am")

Add other messages There are also gnc:msg, gnc:warn and gnc:error functions; see [1] for more details.

Use a Scheme friendly editor For the uninitiated, matching parentheses properly in a Scheme program can make one's eyes cross. A Lisp/Scheme friendly editor can really help here. DrRacket or a properly configured Emacs really helps.

Run often Test your report often after making very small changes. This will make it easier to understand when and where problems are introduced.

Although guile does have debug support, this wiki page updater has not found a way, at this time, to hook GnuCash up to the guile debugger.

Development Environment

Programming tools

Any reasonable source/text editor, including emacs and vi, should provide basic syntax support for source-code editing. One of the most basic and important for editings scheme/lisp sources is parenthesis matching. Other scheme-like environments (such as DrRacket) might also be useful for editing the sources, but note that they might allow constructs that are not valid in guile. Beware Racket is a scheme dialect not 100% compatible with Guile, but provides a nice GUI for understanding scheme functions.

Simple Proposal for Linux

This is a simple proposal for a development environment in Linux. Assume

there is a working directory ~/GnuCash/CustomReports in your home directory.
the new report is stored in the test00.scm file

Here is the proposal how to setup up your environment

cd ~/GnuCash/CustomReports
ln -s test00.scm prototype.scm
cat > config.user << "EOF"
(load "<fullPathTo>/GnuCash/CustomReports/prototype.scm")
EOF
cd ~/.gnucash
ln -s ~/GnuCash/CustomReports/config.user
uuidgen | sed -e s/-//g

Prepare test00.scm to include

the define-module statement

(define-module (gnucash report prototype-report))

following updates in the gnc:define-report statement

'name (N_ "Prototype")
;;'menu-name (N_ "Sample Report with Examples")
'menu-tip (N_ "Unstable. Used for Testing.")
'report-guid "the-new-generated-unique-ID"

See also the minimum report defintion in the #Designing new Reports chapter.

By this you can

use test00.scm as a template test report and use the lines as described above without further changes
collect all our test reports as e.g. testXX.scm files in this directory
switch between them by making the prototype.scm point to the desired report
restart GnuCash
always find the report under Reports->Sample & Custom Report->Prototype

Finally, you should also extract a GnuCash source tar ball in ~/GnuCash/CustomReport/ to have access to the Scheme files referenced in this page.

Technique to reload reports without restarting GnuCash

Reports can be modified to allow the majority of the report to be reloaded without requiring GnuCash to be restarted for each change which is very convenient when developing reports. This requires splitting the report into two files:

a minimal loader which which forces the reload of the meat of your report each time options are generated or report is rendered.
the meat of your report. This contains actual report code for the options generator and renderer.

Both files must parse and execute correctly before the reload will function.

Note that, at least in GnuCash 2.6.17, for changes to report options to take effect, the report must closed and then relaunched from the Report menu. Changes to the render portion seem to be handled just fine by the reload button.

Minimal Example

The following is a skeleton outline of what is required for a report to be reloaded on the fly. Tested with GnuCash 2.6.17.

WARNING: This section is out of date and will not run with GnuCash ≥ 4.6

Minimal Loader

Update name, report-guid and menu-tip values appropriately for your report.

custom_import.scm:

(define-module (custom_import))
(use-modules (gnucash gnc-module))
(use-modules (gnucash gettext))
(gnc:module-load "gnucash/report/report-system" 0)
; load the renderer module once at the top level to get the symbols
(use-modules (custom_import_renderer))

; get and reload the module
(define (reload-report-module)
  (reload-module (resolve-module '(custom_import_renderer))))

; every time options are generated, reload the meat of the report
(define (options_loader)
  (reload-report-module)
  (custom_import_options))

; every time report is rendered, reload the meat of the report
(define (renderer_loader report-obj)
  (reload-report-module)
  (custom_import_renderer report-obj))
 
(gnc:define-report
 'version 1
 'name (N_ "<type your report name here>")
 'report-guid "<paste report unique id here>"
 'menu-tip (N_"<type your report menu tip here>")
 'menu-path (list gnc:menuname-utility)
 'options-generator options_loader
 'renderer renderer_loader)

The Meat of Your Report

custom_import_renderer.scm:

(define-module (custom_import_renderer))
 
; options for the report (called by loader after it reloads this module)
(define (custom_import_options)    
  (let* ((options (gnc:new-options)))  
    ; add your options here       
    options))
 
; report renderer (called by loader after it reloads this module)
(define (custom_import_renderer report-obj) 
  (let ((document (gnc:make-html-document)))
      ; add your renderer here
      document))

(export custom_import_options)
(export custom_import_renderer)

Configuration

You'll also need to edit config.user so that GnuCash can find the files above. Update add-to-load-path value appropriately for your setup.

config.user:

(add-to-load-path "<type the full path to above report files here>")
(use-modules (custom_import))

Designing new Reports

In general, reports are divided into three sections

the Options-Generator (define the options for the report)
the Report-Renderer (create the HTML report)
the gnc:define-report statement (makes the report available in GnuCash)

This is the minimum definition needed for a new GnuCash report. Update name, report-guid^[2] and menu-tip values appropriately.

prototype.scm:

;; -*-scheme-*-

;; This is a minimum report definition in GnuCash.
;; It illustrates the the minimum definitions needed to create
;; a new GnuCash report.
;; It will create an empty page with heading 'Prototype'.
;; To be used as template.

;; ------------------------------------------------------------------
;; Top-level definitions
;; ------------------------------------------------------------------

(define-module (gnucash reports example prototype))

(use-modules (gnucash engine))
(use-modules (gnucash utilities)) 
(use-modules (gnucash core-utils))
(use-modules (gnucash app-utils))
(use-modules (gnucash report))
(use-modules (gnucash html))

(debug-enable 'backtrace)

;; ------------------------------------------------------------------
;; Define the Options for this report
;; ------------------------------------------------------------------

(define (options-generator)    
  (let* ((options (gnc-new-optiondb)))         
    options))

;; ------------------------------------------------------------------
;; Render the HTML document
;; ------------------------------------------------------------------

(define (document-renderer report-obj)
  ;; Helper function for looking up option values
  (define (get-option section name)
    (gnc-optiondb-lookup-value (gnc:report-options report-obj) section name))

  (let* (
         (doc (gnc:make-html-document))
         (report-title (get-option gnc:pagename-general
                                   gnc:optname-reportname))
		)

        (gnc:html-document-add-object!
         doc
         (gnc:make-html-text
          (gnc:html-markup-h3
           (format #f (G_ "~a")
                   report-title))))
    doc))
 
;; ------------------------------------------------------------------
;; Define the actual report
;; ------------------------------------------------------------------

(gnc:define-report
 'version 1
 'name (N_ "Prototype")
 'report-guid "<paste generated unique report id here>"
 'menu-tip (N_ "Unstable. Used for Testing.")
 'menu-path (list gnc:menuname-example)
 'options-generator options-generator
 'renderer document-renderer)

The Options-Generator

Each report takes responsibility to build up an own database that holds the options for the report.

Usually it is a good habit to copy the relavant code from the sample-report.scm. In there you will find the code initializing the database and filling it with options:

(define (options-generator)    
  (let* ((options (gnc-new-optiondb)))         
    options))

Options are directly registered in the option database with a call to gnc-register-<type>-option.

sample-report.scm presents a nice selection of example option definitions of the following types:

gnc-register-simple-boolean-option
gnc-register-multichoice-option
gnc-register-string-option
gnc-register-date-option-set
gnc-register-number-range-option
gnc-register-color-option
gnc-register-account-list-option
gnc-register-list-option

Elsewhere you find:

gnc-register-text-option
gnc-register-font-option
gnc-register-currency-option
gnc-register-budget-option
gnc-register-commodity-option
gnc-register-complex-boolean-option
gnc-register-pixmap-option 
gnc-register-account-list-limited-option
gnc-register-account-sel-option
gnc-register-account-sel-limited-option
gnc-register-multichoice-callback-option
gnc-register-radiobutton-option
gnc-register-radiobutton-callback-option
gnc-register-internal-option
gnc-register-query-option
gnc-register-dateformat-option

Also, business options:

gnc-register-invoice-option
gnc-register-customer-option
gnc-register-vendor-option
gnc-register-employee-option
gnc-register-owner-option
gnc-register-taxtable-option
gnc-register-counter-option
gnc-register-counter-format-option

In general, the syntax for creating an option is:

(define (gnc-register-<type>-option opitiondb
         section                      ;; the tab-string in the option dialog presented to the user
         name                         ;; the text for this option in the option dialog presented to the user
         sort-tag                     ;; used to define the order in which the options are listed
         documentation-string         ;; help string shown when the mouse moved over the option
         default-value
         <optional type specific parameters>)

Note that section is free to be any text string. If section-string has not been used before, a new tab with this name will be created automatically. Nevertheless, note that report-core.scm provides three default names. Re-use these before creating new names:

(define gnc:pagename-general (N_ "General"))
(define gnc:pagename-accounts (N_ "Accounts"))
(define gnc:pagename-display (N_ "Display"))

For a start, simply read through the define (options-generator) statement in sample-report.scm and copy what you need.

Nice to know:

The General option group does not need to be defined, it is part of the report definition per default. If you run the above minimum report definition, the General option group will automatically include a text field for the Report Name, a selection box for the Stylesheet, and a button to Reset defaults.
The guile path can be found in Help -> About -> GNC_DATA by selecting the parent folder.

The Report-Renderer

Define how to apply the options (the actual report contents).

The overall goal of the Report-Renderer is to create an HTML-document and fill it with the report results to display to the user. You should refer to the HTML generation description documentation in the source code.

Similar to Options-Generator, sample-report.scm gives you a great introduction to how this works in general.

The gnc:...-procedures are found in the src/report/report-system/html-*.scm source files.

After runnning the report you can press the Export button to save the generated HTML-Code into a file for viewing. Doing this for the above minimum prototype report gives the following result:

<!DOCTYPE html>
<html dir='auto'>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<style type="text/css">
@media (prefers-color-scheme: dark) {body {color: #000; background-color: #fff;}}
h3 { font-family: "Segoe UI", sans-serif; font-size: 15pt; font-weight: bold;  }
a { font-family: "Segoe UI", sans-serif; font-size: 10pt; font-style: italic;  }
body, p, table, tr, td { vertical-align: top; font-family: "Segoe UI", sans-serif; font-size: 10pt;  }
tr.alternate-row { background: #ffffff }
tr { page-break-inside: avoid !important;}
html, body { height: 100vh; margin-top: 0px; margin-bottom: 0px; margin-left: 8px; margin-right: 8px; }
td, th { border-color: grey }
th.column-heading-left { text-align: left; font-family: "Segoe UI", sans-serif; font-size: 10pt;  }
th.column-heading-center { text-align: center; font-family: "Segoe UI", sans-serif; font-size: 10pt;  }
th.column-heading-right { text-align: right; font-family: "Segoe UI", sans-serif; font-size: 10pt;  }
td.highlight {background-color:#e1e1e1}td.neg { color: red;  }
td.number-cell, td.total-number-cell { text-align: right; white-space: nowrap; }
td.date-cell { white-space: nowrap; }
td.anchor-cell { white-space: nowrap; font-family: "Segoe UI", sans-serif; font-size: 10pt;  }
td.number-cell { font-family: "Segoe UI", sans-serif; font-size: 10pt;  }
td.number-header { text-align: right; font-family: "Segoe UI", sans-serif; font-size: 10pt;  }
td.text-cell { font-family: "Segoe UI", sans-serif; font-size: 10pt;  }
td.total-number-cell { font-family: "Segoe UI", sans-serif; font-size: 10pt; font-weight: bold;  }
td.total-label-cell { font-family: "Segoe UI", sans-serif; font-size: 12pt; font-weight: bold;  }
td.centered-label-cell { text-align: center; font-family: "Segoe UI", sans-serif; font-size: 12pt; font-weight: bold;  }
sub { top: 0.4em; }
sub, sup { vertical-align: baseline; position: relative; top: -0.4em; }
@media print { html, body { height: unset; }}
</style></head><body bgcolor="#ffffff"><h3>Report name</h3>
</body>
</html>

The style section is added automatically without specific definitions inside the prototype source. Also note that the register name in GnuCash is not part of the HTML document.

The procedures to fill this HTML-document with life and further formatting are given in the following report/ source files:

html-acct-table.scm
html-barchart.scm
html-document.scm
html-fonts.scm
html-linechart.scm
html-piechart.scm
html-scatter.scm
html-style-info.scm
html-style-sheet.scm
html-table.scm
html-text.scm
html-utilities.scm

Start making the prototype report a little nicer by adding the following line to the document-renderer from html-document.scm

(gnc:html-document-set-title! document (_ "GnuCash Report Prototype"))

will result in an update of the title and h3 lines:

[...]
<title>GnuCash Report Prototype</title>
[...]
<h3>GnuCash Report Prototype</h3>
[...]

Next it is possible to add attributes to the body line.

Note: You should read the following section for informational purposes only: Style sheets are now the preferred way to specify a document's presentation, the presentational attributes of BODY have been deprecated. (quoted from W3.org) (Currently in GnuCash the `bgcolor`-tag is default part of the `body`-tag.)

The body-tag can be enhanced with attributes via the gnc:html-document-set-style! funtion. The general sytax:

(gnc:html-document-set-style!
    document                               ;; the reference to the current html-document
    "body"                                 ;; specify the tag to add attributes to
    'attribute (list "blabla" "balabala")  ;; first additional attribute
    'attribute (list "nonstop" "nonsens")  ;; second additional attribute
    'attribute (list "bgcolor" "#f6ffdb")  ;; third additional attribute
    [...]                                  ;; further attributes
)

The example above lists some imaginary attributes to indicate that the attribute definition will be added to the body-tag without further validity check. Invalid attributes will appear in the HTML-code but will have no visible effect on the document representation.

The rest of the body is filled with HTML-text by defintion of text objects, which gives the following structure

<body bgcolor="#ffffff">
<h3>[title]</h3>

  [text object 1]
  [text object 2]
    .     .    .
    .     .    .
    .     .    .
  [text object n]

</body>

whereas it does not matter if you define one or more text objects, you can put everything into one object or split it over several objects.

In Scheme these objects are defined like

(gnc:html-document-add-object!
    document               ;; the overall HTML document defined above
    (gnc:make-html-text    ;; a text object
        [text 1]             ;; part 1 of the text
        [text 2]             ;; part 2 of the text
             .   .
             .   .
             .   .
        [text m]             ;; part m of the text
    )
)

Note the above structure is the definition of 1 text object, which consists of m (sub-)text elements.

The text elements can be simple strings, or markup-formatted. Markup-commands are found in html-text.scm:

gnc:html-markup-p        ;; markup for "paragraph"
gnc:html-markup-tt       ;; markup for fixed font (type writer style)
gnc:html-markup-em       ;; markup for "emphasis"
gnc:html-markup-b        ;; markup for "bold"
gnc:html-markup-i        ;; markup for "italic"
gnc:html-markup-h1       ;; markup for headers on level 1
gnc:html-markup-h2       ;; markup for headers on level 2
gnc:html-markup-h3       ;; markup for headers on level 3
gnc:html-markup-br       ;; markup for line "break" (no text)
gnc:html-markup-hr       ;; markup for "horizontal line" (no text)
gnc:html-markup-ul       ;; markup for "unsorted list" (bullet list)
gnc:html-markup-anchor   ;; markup for hyperlinks
gnc:html-markup-img      ;; markup for images

To give you a basic idea, an example of simple text objects:

(gnc:html-document-add-object!
     document
     (gnc:make-html-text 
        "some text" 
        "some other text" 
        (gnc:html-markup-br)
        (gnc:html-markup-tt "tt text")
        (gnc:html-markup-h1 "header1 text")
        (gnc:html-markup "bla" "tirili flöt")
        (gnc:html-markup "i" "italic text")
    )
)

results in following HTML-code

<body bgcolor="#f6ffdb">
<h3>GnuCash Report Prototype</h3>
some text some other text
<br />
<tt>tt text</tt>
<h1>header1 text</h1>
<bla>tirili flöt</bla>
<i>italic text</i>
</body>

Note that it is possible to define new tags (here: "bla") if needed by using gnc:html-markup.

Again: Take a good look at sample-report.scm and explore many more examples how to format HTML-text.

Examine:

html-scatter.scm
html-acct-table.scm
html-piechart.scm
html-table.scm
html-linechart.scm

to find out more about

gnc:make-html-scatter
gnc:make-html-acct-table
gnc:make-html-barchart
gnc:make-html-table
gnc:make-html-linechart

The `gnc:define-report` Statement

If you want to follow the #Simple Proposal for Linux to setup a simple development environment then you need updates to this section only

once that you set up the development environment
once that your report is ready, fully tested, and shall become part of your standard reports

And again, sample-report.scm already proposes how you should proceed in the latter case

[...] 
to contribute your brand new, totally cool report, consult the mailing list "mailto:gnucash-devel@gnucash.org"
[...]

Barcharts

The minimum definition of a bar chart report is shown in the following example based on a simple tutorial for generating charts using html-chart.scm. Before running, update name, report-guid and menu-tip values appropriately.

;; -*-scheme-*-

;; This is a minimum report definition in GnuCash.
;; It illustrates the the minimum definitions needed to create
;; a new GnuCash report.
;; It will create an empty page with heading 'Prototype'.
;; To be used as template.

;; ------------------------------------------------------------------
;; Top-level definitions
;; ------------------------------------------------------------------

(define-module (gnucash reports example prototype))

(use-modules (gnucash engine))
(use-modules (gnucash utilities)) 
(use-modules (gnucash core-utils))
(use-modules (gnucash app-utils))
(use-modules (gnucash report))
(use-modules (gnucash html))

(debug-enable 'backtrace)

;; ------------------------------------------------------------------
;; Define the Options for this report
;; ------------------------------------------------------------------

(define (options-generator)
  (gnc-new-optiondb))

;; ------------------------------------------------------------------
;; Render the HTML document
;; ------------------------------------------------------------------

(define (document-renderer report-obj)
  (let (
        (doc (gnc:make-html-document))
        (chart (gnc:make-html-chart))
       )

       (gnc:html-chart-set-title! chart "title")
       (gnc:html-chart-set-type! chart "bar")
       (gnc:html-chart-set-width! chart '(pixels . 800))
       (gnc:html-chart-set-height! chart '(pixels . 600))
       (gnc:html-chart-set-y-axis-label! chart "yAxis")
       (gnc:html-chart-set-data-labels! chart '("a" "b" "c"))
       (gnc:html-chart-add-data-series! chart "series1" '(20 40 30) "red")
       (gnc:html-chart-add-data-series! chart "series2" '(30 25 25) "green")
       (gnc:html-chart-set! chart '(options chartArea backgroundColor) "wheat")
	   
       (gnc:html-document-add-object!
        doc
        (gnc:make-html-text
         (gnc:html-markup-h3
          (format #f (G_ "~a")
               N_ "Demonstration"))))

       (gnc:html-document-add-object! doc chart)

       doc
  )
)

;; ------------------------------------------------------------------
;; Define the actual report
;; ------------------------------------------------------------------

(gnc:define-report
 'version 1
 'name (N_ "Prototype")
 'report-guid "<paste generated unique report id here>"
 'menu-tip (N_ "Unstable. Used for Testing.")
 'menu-path (list gnc:menuname-utility)
 'options-generator options-generator
 'renderer document-renderer)

If you look at the HMTL source for this report after it is generated, you will see a line with the <img> tag. The image for the report is encoded inline in a very long ASCII code string.

<img src="data:image/png;base64,<very_long_ASCII_coded_string>" alt="Cannot display barchart"/> &nbsp;

The GnuCash API

The GnuCash application programming interface (stable or after the implementation of the first future feature future branch) is quite intimidating, unfortunately. Luckily, for the reports, most of the stuff needed can be found in the scheme sources. Here some random examples of handy procedures (paths shown refer to the location in a source tarball; might be copied into the location as above in your installation):

create a monetary object via gnc:make-gnc-monetary libgnucash/engine/gnc-numeric.scm
get the amount of a monetary object via gnc:gnc-monetary-amount libgnucash/engine/gnc-numeric.scm
get an account name via xaccAccountGetName libgnucash/engine/Account.cpp
create a commodity collector via gnc:make-commodity-collector gnucash/report/report-system/report-utilities.scm

The mightiness of the API is huge. As of GnuCash 2.4.10, there were over 1000 GnuCash api calls that could be made from reports.

It is by far too much to be documented in this Wiki-page.

However, having a table at hand which includes the most common function calls is convenient especially at the start of digging into it.

That is why following table is included in this chapter. The table does not purport to be exhaustive, nor even aim to be, but Scheme-Report developers are invited to add to this table whenever they come across additions of general interest.

Name	Source	Example	Comments
xaccAccountGetBalanceAsOfDate	Account.cpp		Returns the account balance as a number. Example: (xaccAccountGetBalanceAsOfDate acct date)
gnc:html-table-append-row!	html-table.scm		Appends a row to an HTML table. Note that `row` can be a list. If so, then each list element represents a column entry. Example: (gnc:html-table-append-row! table (list e1 e2 e3)) will result in: <tr> <td>e1<td> <td>e2<td> <td>e3<td> </tr> Note that only simple lists are supported for. If you use nested lists as input, then the whole list contents of the nested lists will be displayed.
gnc:gnc-numeric-denom	gnc-numeric.scm		Returns the denominator part of a gnc-numeric record.
gnc:gnc-numeric-num	gnc-numeric.scm		Returns the numerator part of a gnc-numeric record.
gnc-account-get-full-name	gnc_account_get_full_name() in Account.cpp	sample-report.scm	Returns the account name in the format `ParentLevel1:ParentLevel2:...:AccountName` To only get the `AccountName` use `xaccAccountGetName`
xaccTransGetDate	xaccTransGetDate() in Transaction.c		Returns the posting date of a transaction. Transactions are return e.g. by `xaccSplitGetParent`, see below. Note that this function will return the date as numerical value. If you need to have it human readable, you need to convert this numerical value into a date string, like so: (qof-print-date (xaccTransGetDate (xaccSplitGetParent split)))
gnc-window-show-progress	gnc_window_show_progress() in gnc-window.c	report-utilities.scm	Used to forward processing progress information to the user. In `report-utilities.scm` this is wrapped in the routines: `gnc:report-starting` `gnc:report-render-starting gnc:report-percent-done` `gnc:report-finished`
xaccAccountGetDescription	Account.cpp		Returns the account description. To be used with the account as input parameter: (xaccAccountGetDescription acct)
xaccAccountGetName	Account.cpp	sample-report.scm	Returns the account name. To get the full account name including parent names use `gnc-account-get-full-name`
xaccAccountGetNotes	Account.cpp		Returns the account notes. This is the text field that is found in the `edit` dialog of the accounts. To be used with the account as input parameter: (xaccAccountGetNotes acct)
xaccAccountGetSplitList	Account.cpp	report-utilities.scm	Returns the the list of transactions in a given account. Note that in GnuCash each transaction is a split even if it is not a split transaction. A non-split transaction is a transaction consisting of a single split. To get the numerical value for the amount of splits in a list of accounts use `gnc:accounts-count-splits` defined in `report-utilities.scm`. The standard report `cash-flow.scm` makes use of this api.
xaccAccountGetType	Account.cpp		Returns the account type, which is the text field that is found in the `edit` dialog of the accounts. To be used with the account as input parameter `(xaccAccountGetNotes acct)` The following account types are available: `ACCT-TYPE-BANK ACCT-TYPE-CASH ACCT-TYPE-CREDIT ACCT-TYPE-ASSET ACCT-TYPE-LIABILITY ACCT-TYPE-STOCK ACCT-TYPE-MUTUAL ACCT-TYPE-CURRENCY ACCT-TYPE-INCOME ACCT-TYPE-EXPENSE ACCT-TYPE-EQUITY ACCT-TYPE-CHECKING ACCT-TYPE-SAVINGS ACCT-TYPE-MONEYMRKT ACCT-TYPE-RECEIVABLE ACCT-TYPE-PAYABLE ACCT-TYPE-CREDITLINE` `ACCT-TYPE-TRADING`
xaccSplitGetAccount	Split.c		Returns the account object that the split belongs to. To get the name from the returned account, use: (xaccAccountGetName (xaccSplitGetAccount split))
xaccSplitGetCorrAccountName	Split.c		Returns the account name at the other end of the split as a string.
xaccSplitGetParent	Split.c		Returns the parent transaction the split belongs to. See `xaccTransGetDate` for an example how to use it.

Command line access to the API

(Written Jan 2018) It is convenient to access the full API from a Guile Command-line for newbie report developers. This requires the developer is familiar with Linux, and can set up CMake, unit testing environments.

The full GUI-generated reporting construct described above is important to test a custom report, however, is very inconvenient to explore the API.

The preparation work involves:

1. Create a special unit test program in scheme, perhaps naming it test-server.scm - this shall reside in a convenient folder with other unit test files e.g. gnucash/report/standard-reports/test.

(use-modules (gnucash gnc-module))
(use-modules (gnucash app-utils))
(use-modules (gnucash engine test test-extras))

;; The following needed for Guile REPL
(use-modules (system repl server))
(define (run-test)
  (run-server))

;; The following needed for reports:
(use-modules (gnucash report stylesheets))
(use-modules (gnucash report report-system))
(define constructor (record-constructor <report>))

2. Adding test-server.scm onto the CMakeFiles.txt in the same folder to enable compilation

3. Running make or ninja to generate the build directory

4. Running test-server.scm from the build directory by

cd build/gnucash/report/standard-reports/test
/usr/bin/ctest -R test-server

This will run the test server.

5. Switch to another terminal, run

nc localhost 37146 (the default guile port, upside down 37146 looks like guile...)

This will now present a full Guile REPL prompt, with full access to the test-server.scm bindings as well as the Gnucash API. People familiar with emacs and the geiser package may also connect to the server by M-x connect-to-guile. Unfortunately so far, only the environment is loaded. I do not think the file-load mechanism is accessible to scheme, which is an inconvenience for testing reports.

The developer can try:

> ,apropos xacc [RET]
(sw_engine): xaccTransEqual	#<procedure xaccTransEqual (_ _ _ _ _ _)>
(sw_engine): xaccSplitGetCorrAccountCode	#<procedure xaccSplitGetCorrAccountCode (_)>
(sw_engine): xaccAccountGetReconciledBalance	#<procedure xaccAccountGetReconciledBalance (_)>
(sw_engine): xaccClearMarkDown	#<procedure xaccClearMarkDown (_ _)>
(sw_engine): xaccSplitSetBaseValue	#<procedure xaccSplitSetBaseValue (_ _ _)>
(sw_engine): xaccTransGetFirstAPARAcctSplit	#<procedure xaccTransGetFirstAP

etc

> ,apropos gnc- [RET]
(sw_engine): gnc-monetary-list-delete-zeros	#<procedure gnc-monetary-list-delete-zeros (_)>
(sw_engine): gnc-gdate-set-prev-fiscal-year-start	#<procedure gnc-gdate-set-prev-fiscal-year-start (_ _)>
(sw_engine): gnc-quote-source-get-internal-name	#<procedure gnc-quote-source-get-internal-name (_)>
(sw_engine): gnc-numeric-check	#<procedure gnc-numeric-check (_)>
(sw_engine): gnc-timegm	#<procedure gnc-timegm (_)>
(sw_engine): gnc-account-join-children	#<procedure gnc-account-join-c

etc

> ,bindings
constructor             #<variable 55cae1534b70 value: #<procedure 55cae11ff080 at ice-9/boot-9.scm:1340:17 (a b c d e f g h)>>
%module-public-interface #<variable 55cae0652da0 value: #<interface (guile-user) 55cae0638b40>>
run-test                #<variable 55cae1534cc0 value: #<procedure run-test ()>>

> (current-time)
1515297631

> (qof-print-date (current-time))
"07/01/18"

> (qof-date-format-set QOF-DATE-FORMAT-ISO)
> (qof-print-date (current-time))
"2018-01-07"

Adding Menu Items

The following example shows how to add a menu item from Scheme. The code adds the menu item Tools › Scheme REPL and the corresponding command starts a Scheme REPL in the tty.

Installation:

1. Save the code somewhere in your file system like in ~/hacking/gnucash/commands/repl.scm.

2. Add something like this to your ~/.config/gnucash/config-user.scm:

(add-to-load-path "/home/helmut/hacking/gnucash/")
(import (only (commands repl) register-repl-command))
(register-repl-command)

3. Start GnuCash as usual.

Code:

(library (commands repl)
  (export register-repl-command)
  (import (rnrs base)
	  (only (guile) format getenv resolve-module current-module
		set-current-module save-module-excursion)
	  (only (system repl repl) start-repl)
	  (only (ice-9 readline) activate-readline write-history read-history)
	  (only (gnucash gnome-utils) gnc-add-scm-extension)
	  (only (gnucash gnome-utils gnc-menu-extensions) gnc:make-menu-item)
	  (only (gnucash core-utils) G_ N_))

  (define history-filename (format #f "~a/.gnucash_history" (getenv "HOME")))

  (define previous-module #f)

  (define (repl)
    (save-module-excursion
     (lambda ()
       (set-current-module (or previous-module
			       (begin
				 (read-history history-filename)
				 (activate-readline)
				 (resolve-module '(guile-user)))))
       (start-repl)
       (set! previous-module (current-module))
       (write-history history-filename)
       (format #t "Goodbye~%"))))

  (define menuname-tools (N_ "Tools"))

  (define (register-repl-command)
    (gnc-add-scm-extension
     (gnc:make-menu-item
      "Scheme REPL"
      "0155032a4b41443388f6cf8effc98169"
      "Start a Scheme REPL in the tty"
      (list menuname-tools)
      (lambda (window)
	(repl)))))

  )

Other Resources

One other way to create custom reports outside GnuCash, but directly from GnuCash data, is to use Ledger-CLI.

Old GnuCash Report Information

(may be very out of date)

Learning Scheme

MIT Scheme Index
Teach Yourself Scheme in Fixnum Days
Structure and Interpretation of Computer Programs
How to Design Programs and HtDP, 2nd Edition
The Little Schemer
Mastering Scheme is highly eased after reading The Scheme Progamming Language by R. Kent Dybvig
Guile documentation
Some guile code uses pattern matching. An Introduction to Lispy Pattern Matching

↑ Program 'uuidgen' is present in package 'util-linux' and 'sed' in 'sed'.

↑ Table of existing GUIDs: Report GUIDs

[1]

[2]

@@ Line 1: / Line 1: @@
+[[Category:API]] [[Category:Customization]] [[Category:Development‏‎]]
+This documentation applies from '''GnuCash Version 5.0'''. For prior versons use the '''[https://wiki.gnucash.org/wiki/index.php?title=Custom_Reports&oldid=21603 previous version]'''.
 == Custom Reports in GnuCash ==
-Unfortunately, at the present time writing a custom report for GnuCash requires a little bit of hacking. This wiki page should contain some information to help you get started, since there is no official documentation.
+The term ''Custom Reports'' has several contexts in GnuCash:
+* Customizing settings for standard reports ([[Using GnuCash#Saved Report Configurations]])
+* Combining selected standard reports into one view ([[Using GnuCash#Custom Multicolumn Report]])
+* Customized output format for reports ([[Custom Reports Using Eguile]])
+* Reports written in the Scheme programming language which are not delivered as part of the standard reports (this page)
+If you are not up for coding, you should check the
+* report options
+* stylesheets and
+* stylesheet options and
+* file properties.
+Possibly there are ways to get what you desire without coding.
+If you are ready for coding (and even already firm in Scheme and Guile) then this is the place to contribute.
+== Introduction ==
+Custom reports can be fairly challenging and while the information presented here is brief it should be enough to get you started. The focus is on enough understanding to change (hack) existing reports.
+In the GnuCash project the reports are coded in ''Scheme'', not in ''C''. Understanding Scheme is one of the prerequisites to create new reports.
+The obvious drawback is that one must learn yet another programming language (if not already familiar with it) but saves the effort of having to alter and build GnuCash's source code.
+''Guile'' is used as an interface to get the ''Scheme'' code executed during runtime. Again, if not already familiar with it, this is the second piece of work that one has to swallow.
+Last, but not least, the API for that sort of thing is not formally specified.
+Still reading? Not yet discouraged? Good for you! Thankfully, lots of help is available.
+First of all, there is good educational material available on the web to help you learn Scheme and Guile. Secondly, there is a simple <tt>sample-report.scm</tt> example report specifically written to show you the base layout of a GnuCash report. And finally, this Wiki page will give you some guidance when starting this venture.
+== Getting Started ==
+This tutorial will give you an overview of GnuCash reports and might give you the confidence to make simple changes to existing reports.
+=== Appreciation of ''Scheme'' language ===
+GnuCash reports are written in the Scheme programming language. For a quick introduction try [https://artanis.dev/scheme.html Learn Scheme in 15 minutes] using an [https://replit.com/languages/scheme online scheme repl].
+=== Language details ===
+This tutorial is self-contained but to extend it in reports you'll want to use the following references and learn about the language. Just be aware of them for now.
+==== Get to know ''Scheme'' ====
+* Mastering Scheme is much easier if you've read [https://www.scheme.com/tspl4/ The Scheme Programming Language] by R. Kent Dybvig.
+If you are new to ''Scheme'' it is not necessary to read and understand all of it right now. For anything more than this tutorial you should, at least, have gone through the [https://www.scheme.com/tspl4/start.html#./start:h0 Getting Started] section.
+==== Get to know ''Guile'' ====
+Guile is used internally by GnuCash to ''interpret'' the Scheme reports.
+* [{{URL:guile}}docs/docs.html Guile documentation]
+This comes with a marvelous [{{URL:guile}}docs/guile-tut/tutorial.html Tutorial]. You don't need this for writing the reports themselves, but it gives a clue of how reports are created in GnuCash. This should be good motivation to go and tackle the learning curve for ''Scheme''.
+==== Get to know ''Gettext'' ====
+That is the tool which makes the strings translatable. <syntaxhighlight lang="scm" inline>(G_ "Some Text")</syntaxhighlight>, <syntaxhighlight lang="scm" inline>(N_ "Some Text")</syntaxhighlight> and similar mark the text for translation. See [[I18N#How to make strings in code translatable]] for details.
+<references />
+=== Where to find existing reports ===
+The location of existing reports varies with by operating systems. The <tt>guile</tt> path can be found in <tt>Help -> About -> GNC_DATA</tt> by selecting the parent folder.:
+{| class="wikitable"
+|-
+!scope="col" style="width: 150px;" | Operating System
+!scope="col"| Path
+|-
+!scope="row"| All Linux except Debian with flatpak including derivatives such as UbuntuBSD
+| <tt>.../<''guile-version''>/gnucash/reports</tt>
+|-
+!scope="row"| Debian with flatpak including derivatives such as Ubuntu, OSX bundle (Gnucash.app), Windows
+| <tt>.../guile/site/2.2/gnucash/reports</tt>
+|}
+=== Study some example reports ===
+==== sample-report ====
+<tt>sample-report.scm</tt> was created in GnuCash V5.0 from <tt>hello-world.scm</tt> to demonstrate the basic structure of a report. Don't get too confused by the huge number of options that are shown in this report - they were added to show off the variety of options available in GnuCash.
+Have a look under [[#Where to find existing reports]] to find the source code for this report. Alternatively, you can browse [https://github.com/Gnucash/gnucash/blob/stable/gnucash/report/reports/example/sample-report.scm the current source code for this report on github].
+By looking at the result of this report while you study the source code, you will easily get clues to how it functions. You can run this report in GnuCash via the menu: Reports -> Examples -> Sample Report
+==== account-piecharts ====
+If you want to walk through a much more complicated report, study [https://github.com/Gnucash/gnucash/blob/65bb60d62182d17eeb885f25976bc49767068ee3/gnucash/report/standard-reports/account-piecharts.scm <tt>account-piecharts.scm</tt>].
+There are two long functions in this report.
+# [https://github.com/Gnucash/gnucash/blob/65bb60d62182d17eeb885f25976bc49767068ee3/gnucash/report/standard-reports/account-piecharts.scm#L86 <code>option-generator</code>] defines the options for this report.
+# [https://github.com/Gnucash/gnucash/blob/65bb60d62182d17eeb885f25976bc49767068ee3/gnucash/report/standard-reports/account-piecharts.scm#L354 <code>piechart-renderer</code>] makes all the calculations and renders the pie chart.
+The list of values to be shown in the pie chart can be calculated in two ways - [https://github.com/Gnucash/gnucash/blob/65bb60d62182d17eeb885f25976bc49767068ee3/gnucash/report/standard-reports/account-piecharts.scm#L322 depth-based] or [https://github.com/Gnucash/gnucash/blob/65bb60d62182d17eeb885f25976bc49767068ee3/gnucash/report/standard-reports/account-piecharts.scm#L282 via a method that traverses all accounts]. The decision for this is made when [https://github.com/Gnucash/gnucash/blob/65bb60d62182d17eeb885f25976bc49767068ee3/gnucash/report/standard-reports/account-piecharts.scm#L642 calling the <code>piechart-renderer</code> function]. Both methods will work from a list of selected accounts stored in the [https://github.com/Gnucash/gnucash/blob/65bb60d62182d17eeb885f25976bc49767068ee3/gnucash/report/standard-reports/account-piecharts.scm#L404 <code>topl-accounts</code> variable].
+[https://github.com/Gnucash/gnucash/blob/65bb60d62182d17eeb885f25976bc49767068ee3/gnucash/report/standard-reports/account-piecharts.scm#L282 <code>traverse-accounts</code>] is a recursive function that [https://github.com/Gnucash/gnucash/blob/65bb60d62182d17eeb885f25976bc49767068ee3/gnucash/report/standard-reports/account-piecharts.scm#L294 calls itself] to traverse through all child accounts in the account tree. To get the balance for a single account, it makes a [https://github.com/Gnucash/gnucash/blob/65bb60d62182d17eeb885f25976bc49767068ee3/gnucash/report/standard-reports/account-piecharts.scm#L482 call to <code>profit-fn</code>].  [https://github.com/Gnucash/gnucash/blob/65bb60d62182d17eeb885f25976bc49767068ee3/gnucash/report/standard-reports/account-piecharts.scm#L418 <code>profit-fn</code>] obtains the account balance for either one interval or at a given date. It calls out to [https://github.com/Gnucash/gnucash/blob/65bb60d62182d17eeb885f25976bc49767068ee3/gnucash/report/report-system/report-utilities.scm#L502 <code>gnc:account-get-comm-balance-at-date</code> in <tt>report-utilities.scm</tt>] where, finally, lower level calls are made, which create a query for the account balance at the given date.
+Well, long story short, this report is rather involved. Sorry.
+=== Setup a prototype report ===
+Even if you haven't ever written a report before, and you don't have a shiny track record of great ''Scheme'' experience, setting up a prototype at this moment will have the benefits getting productive after some time of pure theory.
+The beginners amongst us might not have a final picture of what report to write. No worries, take the <tt>[[Custom_Reports#sample-report_report|sample-report.scm]]</tt> report source file, store it in your preferred working directory, and rename it to a unique name, say <tt>my-world.scm</tt>.
+As, for sure, you already have read through this report, you know that this report is very wordy, giving a lot of text printouts. These can be used to easily see your own first changes on the screen once this prototype is loaded into GnuCash, and even better, it will let you differentiate between the <tt>my-world.scm</tt> that you have loaded and the <tt>sample-report.scm</tt> that is available in GnuCash by default (see previous section). So feel free to implement some fancy printout changes.
+==== Prerequisites ====
+''GnuCash'' will not be able to load your report until you make changes in two areas of your report source file:
+===== Give report a unique symbol name =====
+To avoid symbol definition conflicts with other reports, make sure your report code begins with a '''define-module statement''' with a report name not used by any other report, for example:
+ (define-module (gnucash report <span style="color:green">my-world-report</span>))
-Note: I am using GnuCash 2.0.1 as I write this.
+===== Define report with unique name and id =====
+To enable ''GnuCash'' to register your report into the Report menu, scroll to the end of the code and update the '''gnc:define-report statement'''.
-=== Update June 2009 ===
+Set the '''name''' of your report to be shown in the  Report menu. This name must be unique across all reports.
-A new method of creating an improved report formatting is now available.  See [[Custom Reports Using Eguile]].
+  'name (N_ "<span style="color:green">My World</span>")
-=== Example Reports ===
+Further down below, if it is present, comment out the '''menu-name''' line:
-A good place to start is to examine the source code of the reports included with GnuCash. The location varies a little with different operating systems:
+<pre>;;'menu-name (N_ "Sample Report with Examples")</pre>
-* On BSD look in <tt>/usr/local/share/gnucash/guile-modules/gnucash/report</tt>
-* On OpenSuse look in <tt>/opt/gnome/share/gnucash/guile-modules/gnucash/report</tt>
-* On Gentoo, Ubuntu, Foresight look in <tt>/usr/share/gnucash/guile-modules/gnucash/report</tt>
-* On Windows look in <tt>C:\Program Files\gnucash\share\gnucash\guile-modules\gnucash\report</tt>
-<tt>hello-world.scm</tt> is specially written to demonstrate the basic structure of a report. However, don't get too confused by the huge number of options which are shown in that report - those were just added to show off the variety of options which are available inside gnucash.
+Update the '''tool tip''' text to something appropriate for your report:
+ 'menu-tip (N_ "<span style="color:green">Unstable. Used for Testing.</span>")
-=== The GnuCash API ===
+Your report must have a globally unique identifier (guid). GnuCash will fail to start if multiple reports have the same unique id. For this reason, if you wish to create a backup of a report while you work on it, place the backup outside the GnuCash directories. If you need some newly generated unique id, use an online uuid generator like [https://www.guidgenerator.com/ this one] (any other one will do as well). Be sure to untick "Hyphens" to generate gnucash compatible guids. If you forget or the site you use doesn't offer that option, simply remove the hyphens yourself.
-The GnuCash application programming interface is quite intimidating, unfortunately. Luckily, for the reports, most of the stuff needed can be found in the scheme sources. Here some random examples of handy procedures  (paths shown refer to the location in a source tarball; might be copied into the location as above in your installation):
-* create a monetary object: gnc:make-gnc-monetary <tt>src/engine/gnc-numeric.scm</tt>
-* get the amount of a monetary object: gnc:gnc-monetary-amount <tt>src/engine/gnc-numeric.scm</tt>
-* get an account name: gnc-account-get-name <tt>src/engine/swig-engine.c</tt>
-* create a commodity collector: gnc:make-commodity-collector <tt>src/report/report-system/report-utilities.scm</tt>
-Watch out for the gnucash version in use: In '''2.0.x''', the Scheme wrappers were created by G-WRAP, started with <tt>gnc:</tt> (with a colon) and were written into scheme files of the name gw-something.scm. In '''2.1.x and later''', the Scheme wrappers are created by SWIG, start with <tt>gnc-</tt> (a dash, not a colon) and were written into C files of the name swig-something.c. Please keep that in mind if the old documentation points you towards functions like these: Get an account name: ''gnc:account-get-name'' <tt>src/engine/gw-engine-spec.scm</tt> - such a function would now be called ''gnc-account-get-name'' and would be found in <tt>src/engine/engine.i</tt> or the generated file <tt>src/engine/swig-engine.c</tt>.
+Alternatively, in linux, run this construct <syntaxhighlight lang="sh">
+uuidgen | sed -e 's/-//g'
+</syntaxhighlight><ref>Program 'uuidgen' is present in package 'util-linux' and 'sed' in 'sed'.</ref>
+Copy the newly generated ID and paste it into the '''report-guid''' value:
+ 'report-guid "<span style="color:red">paste generated report unique id here</span>"
+=== Loading Your Report ===
+There are ''two ways to load a report'' at startup of GnuCash:
+* from a user account or
+* from the installation tree.
+You will likely want to use the user account approach - a least until your work is finished.
+==== Load the report from a user account ====
+This method is used if you edit your report source file in a working directory.
+* Edit [[Configuration_Locations#GNC_CONFIG_HOME|GNC_CONFIG_HOME]]/<tt>config-user.scm</tt> to add a line of the form:
+<SyntaxHighlight lang="scheme">
+(load (gnc-build-userdata-path "my-world.scm"))
+</SyntaxHighlight>
+;Notes:
+:* ''(gnc-build-userdata-path ...)'' or ''(gnc-build-dotgnucash-path ...)'' will complement your report name with the full path of your [[Configuration_Locations#GNC_DATA_HOME|GNC_DATA_HOME]] or [[Configuration_Locations#DOT_GNUCASH_DIR|DOT_GNUCASH_DIR]] directory respectively. If you are comfortable with file locations you could equally well use the form
+:<SyntaxHighlight lang="scheme">
+(load "<absolute path to>/my-world.scm")
+</SyntaxHighlight>
+::to load your report from any arbitrary location on your file system.
+:* The instructions refer to two separate directories: [[Configuration_Locations#GNC_CONFIG_HOME|GNC_CONFIG_HOME]] and [[Configuration_Locations#GNC_DATA_HOME|GNC_DATA_HOME]]. Be careful to use the proper one in the different locations as indicated.
+:*If the <tt>config.user</tt> or <tt>config-user.scm</tt> file is not yet found in your settings directory, simply create it.
+Move, copy, or link* your report file (<tt>my-world.scm</tt>) from your working directory to the proper [[Configuration_Locations#GNC_DATA_HOME|GNC_DATA_HOME]] or [[Configuration_Locations#DOT_GNUCASH_DIR|DOT_GNUCASH_DIR]] directory. The report should be visible in the Reports menu after the next restart.
+<tt>*</tt> On Unix-like OSs you can use the <tt>ln</tt> command; on Windows (7 and higher) you can use the <tt>mklink</tt> command.
+To reload your report, you must '''restart''' GnuCash. You will have to do this '''every time''' you change a report.
+==== Load the report from the installed report directory ====
+{| class="wikitable"
+|-
+|'''Tip:''' Despite the warning below, this can be the easiest method in Windows by sandboxing report development with a [https://sourceforge.net/projects/portableapps/files/GnuCash%20Portable/ <tt>Portable Apps version</tt>]. Since GnuCash 4.12 the portable <tt>guile</tt> path can be found in <tt>Help -> About -> GNC_DATA</tt> by selecting the parent folder.
+|}
+While not recommended you can also copy the report to the installed report directory.  Make sure you have included a module definition as shown above.  All <tt>*.scm</tt> files from the <tt>gnucash/scm/gnucash/report/standard-reports/</tt> directory will be loaded automatically. This applies ''only'' to the <tt>standard-reports/</tt> sub-directory, not to any of the other directories with reports. Hence, the easiest way to have your report available to gnucash is to copy your *.scm file into that directory.
+;Note: In case of an eguile based report only the foo.scm file should be stored in the standard-reports directory. The accompanying <tt>foo.eguile.scm</tt> and <tt>foo.css</tt> should go in to <tt>gnucash/scm/gnucash/report</tt> instead.
+Then '''restart''' GnuCash. You will have to do this '''every time''' you change the report definition file.
+=== Debugging your report ===
+When guile cannot make sense of your report, or your report throws an error, GnuCash will present the following error message in place of your report:
+{| class="wikitable"
+|-
+|'''Report error'''
+An error occurred while running the report.
+|}
+This lets you know there was a problem, but now you need to pinpoint where the problem lies.  Here are some tips that might help.
+{| class="wikitable"
+|-
+! scope = "col" | Tip
+! scope = "col" | Details
+|- style="vertical-align:top;"
+| Enable debug messages
+| Start GnuCash with debug command line parameters: <syntaxhighlight lang="sh">gnucash --debug --log gnc.scm=debug</syntaxhighlight>
+On macOS, assuming GnuCash is in your <code>/Applications</code> folder, this would be:
+<syntaxhighlight lang="sh>/Applications/Gnucash.app/Contents/MacOS/Gnucash --debug --log gnc.scm=debug</syntaxhighlight>
+There are other debug related options, run GnuCash with the <code>--help</code> for a complete list.
+|- style="vertical-align:top;"
+| Study the trace logs
+| The GnuCash trace logs can sometimes give you that satisfying "oh, I see". By default you'll find the trace log:
+{| class="wikitable"
+|-
+! scope ="col" | Operating System
+! scope ="col" | Location
+|- style="vertical-align:top;"
+| Unix/Linux
+| <code>$TEMP/gnucash.something.trace</code>
+|- style="vertical-align:top;"
+| Windows
+| <code>%TEMP%/gnucash.something.trace</code>
+|- style="vertical-align:top;"
+| macOS
+| Somewhere under <code>/var/folders/</code> You can find it via:
+<syntaxhighlight lang="sh">find /var/folders -name "gnucash.trace" 2> /dev/null</syntaxhighlight>
+|}
+You can change the trace log file location via GnuCash command line parameter <code>--logto</code>. This parameter includes support for logging to <code>'stderr'</code> and <code>'stdout'</code>
+|- style="vertical-align:top;"
+| Add your own debug messages
+| You can use the <code>gnc:debug</code> function to add your own messages.  For example: <syntaxhighlight lang="scheme">(gnc:debug "here I am")</syntaxhighlight>
+|- style="vertical-align:top;"
+| Add other messages
+| There are also <code>gnc:msg</code>, <code>gnc:warn</code> and <code>gnc:error</code> functions; see [https://github.com/Gnucash/gnucash/blob/unstable/libgnucash/scm/utilities.scm] for more details.
+|- style="vertical-align:top;"
+| Use a Scheme friendly editor
+| For the uninitiated, matching parentheses properly in a Scheme program can make one's eyes cross. A Lisp/Scheme friendly editor can really help here. DrRacket or a properly configured Emacs really helps.
+|- style="vertical-align:top;"
+| Run often
+| Test your report often after making very small changes.  This will make it easier to understand when and where problems are introduced.
+|}
+Although guile does have debug support, this wiki page updater has not found a way, at this time, to hook GnuCash up to the guile debugger.
+== Development Environment ==
 === Programming tools ===
-Any reasonable source/text editor, including emacs and vi, should provide basic syntax support for source-code editing.  One of the most basic and important for editings scheme/lisp sources is parenthesis matching.  Other scheme environments (such as [http://www.drscheme.org/ drScheme]) might also be useful for editing the sources, but note that they might allow constructs that are not valid in guile.
+Any reasonable source/text editor, including emacs and vi, should provide basic syntax support for source-code editing.  One of the most basic and important for editings scheme/lisp sources is parenthesis matching.  Other scheme-like environments (such as [https://racket-lang.org/ DrRacket]) might also be useful for editing the sources, but note that they might allow constructs that are not valid in guile. Beware Racket is a scheme dialect not 100% compatible with Guile, but provides a nice GUI for understanding scheme functions.
+=== Simple Proposal for Linux ===
+This is a simple proposal for a development environment in Linux.
+Assume
+* there is a working directory <code>~/GnuCash/CustomReports</code> in your home directory.
+* the new report is stored in the <tt>test00.scm</tt> file
+Here is the proposal how to setup up your environment
+<syntaxhighlight lang="sh">
+cd ~/GnuCash/CustomReports
+ln -s test00.scm prototype.scm
+cat > config.user << "EOF"
+(load "<fullPathTo>/GnuCash/CustomReports/prototype.scm")
+EOF
+cd ~/.gnucash
+ln -s ~/GnuCash/CustomReports/config.user
+uuidgen | sed -e s/-//g
+</syntaxhighlight>
+Prepare <tt>test00.scm</tt> to include
+* the define-module statement
+<syntaxhighlight lang="scheme">(define-module (gnucash report prototype-report))</syntaxhighlight>
+* following updates in the <code>gnc:define-report</code> statement
+<syntaxhighlight lang="Scheme">'name (N_ "Prototype")
+;;'menu-name (N_ "Sample Report with Examples")
+'menu-tip (N_ "Unstable. Used for Testing.")
+'report-guid "the-new-generated-unique-ID"</syntaxhighlight>
+See also the minimum report defintion in the [[#Designing new Reports]] chapter.
+By this you can
+* use <tt>test00.scm</tt> as a template test report and use the lines as described above without further changes
+* collect all our test reports as e.g. testXX.scm files in this directory
+* switch between them by making the prototype.scm point to the desired report
+* restart GnuCash
+* always find the report under ''Reports->Sample & Custom Report->Prototype''
+Finally, you should also extract a ''GnuCash'' source tar ball in <code>~/GnuCash/CustomReport/</code> to have access to the ''Scheme'' files referenced in this page.
+=== Technique to reload reports without restarting GnuCash ===
+Reports can be modified to allow the majority of the report to be
+reloaded without requiring GnuCash to be restarted for each change
+which is very convenient when developing reports.  This requires splitting
+the report into two files:
+# a minimal loader which which forces the reload of the meat of your report each time options are generated or report is rendered.
+# the meat of your report.  This contains actual report code for the options generator and renderer.
+Both files must parse and execute correctly before the reload will function.
+Note that, at least in GnuCash 2.6.17, for changes to report options to take effect,  the report must closed and then relaunched from the Report menu. Changes to the render portion seem to be handled just fine by the reload button.
+====Minimal Example ====
+The following is a skeleton outline of what is required for a report
+to be reloaded on the fly. Tested with GnuCash 2.6.17.
+;WARNING: This section is out of date and will not run with GnuCash &ge; 4.6
+=====Minimal Loader  =====
+Update <code>name</code>, <code>report-guid</code> and <code>menu-tip</code> values appropriately for your report.
+custom_import.scm:
+<syntaxhighlight lang="scheme" highlight="24-26">
+(define-module (custom_import))
+(use-modules (gnucash gnc-module))
+(use-modules (gnucash gettext))
+(gnc:module-load "gnucash/report/report-system" 0)
+; load the renderer module once at the top level to get the symbols
+(use-modules (custom_import_renderer))
+; get and reload the module
+(define (reload-report-module)
+  (reload-module (resolve-module '(custom_import_renderer))))
+; every time options are generated, reload the meat of the report
+(define (options_loader)
+  (reload-report-module)
+  (custom_import_options))
+; every time report is rendered, reload the meat of the report
+(define (renderer_loader report-obj)
+  (reload-report-module)
+  (custom_import_renderer report-obj))
+(gnc:define-report
+ 'version 1
+ 'name (N_ "<type your report name here>")
+ 'report-guid "<paste report unique id here>"
+ 'menu-tip (N_"<type your report menu tip here>")
+ 'menu-path (list gnc:menuname-utility)
+ 'options-generator options_loader
+ 'renderer renderer_loader)
+</syntaxhighlight>
+=====The Meat of Your Report =====
+custom_import_renderer.scm:
+<syntaxhighlight lang="scheme">
+(define-module (custom_import_renderer))
+; options for the report (called by loader after it reloads this module)
+(define (custom_import_options)
+  (let* ((options (gnc:new-options)))
+    ; add your options here
+    options))
+; report renderer (called by loader after it reloads this module)
+(define (custom_import_renderer report-obj)
+  (let ((document (gnc:make-html-document)))
+      ; add your renderer here
+      document))
+(export custom_import_options)
+(export custom_import_renderer)
+</syntaxhighlight>
+=====Configuration =====
+You'll also need to edit config.user so that GnuCash can find the files above.
+Update <code>add-to-load-path</code> value appropriately for your setup.
+config.user:
+<syntaxhighlight lang="scheme" highlight="1">
+(add-to-load-path "<type the full path to above report files here>")
+(use-modules (custom_import))
+</syntaxhighlight>
+== Designing new Reports ==
+In general, reports are divided into three sections
+* the Options-Generator (define the options for the report)
+* the Report-Renderer (create the HTML report)
+* the <code>gnc:define-report</code> statement (makes the report available in ''GnuCash'')
+This is the minimum definition needed for a new ''GnuCash'' report. Update <code>name</code>, <code>report-guid</code><ref>Table of existing GUIDs: [[Report GUIDs]]</ref> and <code>menu-tip</code> values appropriately.
+prototype.scm:
+<syntaxhighlight lang="scheme" highlight="13,61-63">
+;; -*-scheme-*-
+;; This is a minimum report definition in GnuCash.
+;; It illustrates the the minimum definitions needed to create
+;; a new GnuCash report.
+;; It will create an empty page with heading 'Prototype'.
+;; To be used as template.
+;; ------------------------------------------------------------------
+;; Top-level definitions
+;; ------------------------------------------------------------------
+(define-module (gnucash reports example prototype))
+(use-modules (gnucash engine))
+(use-modules (gnucash utilities))
+(use-modules (gnucash core-utils))
+(use-modules (gnucash app-utils))
+(use-modules (gnucash report))
+(use-modules (gnucash html))
+(debug-enable 'backtrace)
+;; ------------------------------------------------------------------
+;; Define the Options for this report
+;; ------------------------------------------------------------------
+(define (options-generator)
+  (let* ((options (gnc-new-optiondb)))
+    options))
+;; ------------------------------------------------------------------
+;; Render the HTML document
+;; ------------------------------------------------------------------
+(define (document-renderer report-obj)
+  ;; Helper function for looking up option values
+  (define (get-option section name)
+    (gnc-optiondb-lookup-value (gnc:report-options report-obj) section name))
+  (let* (
+         (doc (gnc:make-html-document))
+         (report-title (get-option gnc:pagename-general
+                                   gnc:optname-reportname))
+		)
+        (gnc:html-document-add-object!
+         doc
+         (gnc:make-html-text
+          (gnc:html-markup-h3
+           (format #f (G_ "~a")
+                   report-title))))
+    doc))
+;; ------------------------------------------------------------------
+;; Define the actual report
+;; ------------------------------------------------------------------
+(gnc:define-report
+ 'version 1
+ 'name (N_ "Prototype")
+ 'report-guid "<paste generated unique report id here>"
+ 'menu-tip (N_ "Unstable. Used for Testing.")
+ 'menu-path (list gnc:menuname-example)
+ 'options-generator options-generator
+ 'renderer document-renderer)</syntaxhighlight>
+=== The Options-Generator ===
+Each report takes responsibility to build up an own database that holds the options for the report.
+Usually it is a good habit to copy the relavant code from the <tt>sample-report.scm</tt>.
+In there you will find the code initializing the database and filling it with options:
+<syntaxhighlight lang="scheme">
+(define (options-generator)
+  (let* ((options (gnc-new-optiondb)))
+    options))
+</syntaxhighlight>
+Options are directly registered in the option database with a call to <code>gnc-register-<type>-option</code>.
+<tt>sample-report.scm</tt> presents a nice selection of example option definitions of the following types:
+<syntaxhighlight lang="scheme">
+gnc-register-simple-boolean-option
+gnc-register-multichoice-option
+gnc-register-string-option
+gnc-register-date-option-set
+gnc-register-number-range-option
+gnc-register-color-option
+gnc-register-account-list-option
+gnc-register-list-option
+</syntaxhighlight>
+Elsewhere you find:
+<syntaxhighlight lang="scheme">
+gnc-register-text-option
+gnc-register-font-option
+gnc-register-currency-option
+gnc-register-budget-option
+gnc-register-commodity-option
+gnc-register-complex-boolean-option
+gnc-register-pixmap-option
+gnc-register-account-list-limited-option
+gnc-register-account-sel-option
+gnc-register-account-sel-limited-option
+gnc-register-multichoice-callback-option
+gnc-register-radiobutton-option
+gnc-register-radiobutton-callback-option
+gnc-register-internal-option
+gnc-register-query-option
+gnc-register-dateformat-option
+</syntaxhighlight>
+Also, business options:
+<syntaxhighlight lang="scheme">
+gnc-register-invoice-option
+gnc-register-customer-option
+gnc-register-vendor-option
+gnc-register-employee-option
+gnc-register-owner-option
+gnc-register-taxtable-option
+gnc-register-counter-option
+gnc-register-counter-format-option
+</syntaxhighlight>
+In general, the syntax for creating an option is:
+<syntaxhighlight lang="scheme">
+(define (gnc-register-<type>-option opitiondb
+         section                      ;; the tab-string in the option dialog presented to the user
+         name                         ;; the text for this option in the option dialog presented to the user
+         sort-tag                     ;; used to define the order in which the options are listed
+         documentation-string         ;; help string shown when the mouse moved over the option
+         default-value
+         <optional type specific parameters>)
+</syntaxhighlight>
+Note that <code>section</code> is free to be any text string. If section-string has not been used before, a new tab with this name will be created automatically. Nevertheless, note that <tt>report-core.scm</tt> provides three default names. Re-use these before creating new names:
+<syntaxhighlight lang="scheme">
+(define gnc:pagename-general (N_ "General"))
+(define gnc:pagename-accounts (N_ "Accounts"))
+(define gnc:pagename-display (N_ "Display"))
+</syntaxhighlight>
+For a start, simply read through the <code>define (options-generator)</code> statement in <tt>sample-report.scm</tt> and copy what you need.
+Nice to know:
+* The ''General'' option group does not need to be defined, it is part of the report definition per default. If you run the above minimum report definition, the ''General'' option group will automatically include a text field for the <code>Report Name</code>, a selection box for the <code>Stylesheet</code>, and a button to <code>Reset defaults</code>.
+* The <tt>guile</tt> path can be found in <tt>Help -> About -> GNC_DATA</tt> by selecting the parent folder.
+=== The Report-Renderer ===
+Define how to apply the options (the actual report contents).
+The overall goal of the ''Report-Renderer'' is to create an ''HTML''-document and fill it with the report results to display to the user. You should refer to the [https://github.com/Gnucash/gnucash/blob/stable/gnucash/report/doc/report-html.txt HTML generation description] documentation in the source code.
+Similar to ''Options-Generator'', <tt>sample-report.scm</tt> gives you a great introduction to how this works in general.
+The <code>gnc:...</code>-procedures are found in the <tt>src/report/report-system/html-*.scm</tt> source files.
+After runnning the report you can press the <code>Export</code> button to save the generated ''HTML-Code'' into a file for viewing. Doing this for the above minimum prototype report gives the following result:
+<syntaxhighlight lang="html">
+<!DOCTYPE html>
+<html dir='auto'>
+<head>
+<meta http-equiv="content-type" content="text/html; charset=utf-8" />
+<style type="text/css">
+@media (prefers-color-scheme: dark) {body {color: #000; background-color: #fff;}}
+h3 { font-family: "Segoe UI", sans-serif; font-size: 15pt; font-weight: bold;  }
+a { font-family: "Segoe UI", sans-serif; font-size: 10pt; font-style: italic;  }
+body, p, table, tr, td { vertical-align: top; font-family: "Segoe UI", sans-serif; font-size: 10pt;  }
+tr.alternate-row { background: #ffffff }
+tr { page-break-inside: avoid !important;}
+html, body { height: 100vh; margin-top: 0px; margin-bottom: 0px; margin-left: 8px; margin-right: 8px; }
+td, th { border-color: grey }
+th.column-heading-left { text-align: left; font-family: "Segoe UI", sans-serif; font-size: 10pt;  }
+th.column-heading-center { text-align: center; font-family: "Segoe UI", sans-serif; font-size: 10pt;  }
+th.column-heading-right { text-align: right; font-family: "Segoe UI", sans-serif; font-size: 10pt;  }
+td.highlight {background-color:#e1e1e1}td.neg { color: red;  }
+td.number-cell, td.total-number-cell { text-align: right; white-space: nowrap; }
+td.date-cell { white-space: nowrap; }
+td.anchor-cell { white-space: nowrap; font-family: "Segoe UI", sans-serif; font-size: 10pt;  }
+td.number-cell { font-family: "Segoe UI", sans-serif; font-size: 10pt;  }
+td.number-header { text-align: right; font-family: "Segoe UI", sans-serif; font-size: 10pt;  }
+td.text-cell { font-family: "Segoe UI", sans-serif; font-size: 10pt;  }
+td.total-number-cell { font-family: "Segoe UI", sans-serif; font-size: 10pt; font-weight: bold;  }
+td.total-label-cell { font-family: "Segoe UI", sans-serif; font-size: 12pt; font-weight: bold;  }
+td.centered-label-cell { text-align: center; font-family: "Segoe UI", sans-serif; font-size: 12pt; font-weight: bold;  }
+sub { top: 0.4em; }
+sub, sup { vertical-align: baseline; position: relative; top: -0.4em; }
+@media print { html, body { height: unset; }}
+</style></head><body bgcolor="#ffffff"><h3>Report name</h3>
+</body>
+</html>
+</syntaxhighlight>
+The style section is added automatically without specific definitions inside the prototype source.
+Also note that the register name in ''GnuCash'' is not part of the ''HTML'' document.
+The procedures to fill this ''HTML''-document with life and further formatting are given in the following <code>report/</code> source files:
+<pre>
+html-acct-table.scm
+html-barchart.scm
+html-document.scm
+html-fonts.scm
+html-linechart.scm
+html-piechart.scm
+html-scatter.scm
+html-style-info.scm
+html-style-sheet.scm
+html-table.scm
+html-text.scm
+html-utilities.scm
+</pre>
+Start making the prototype report a little nicer by adding the following line to the <code>document-renderer</code> from <tt>html-document.scm</tt>
+<syntaxhighlight lang="scheme">
+(gnc:html-document-set-title! document (_ "GnuCash Report Prototype"))
+</syntaxhighlight>
+will result in an update of the <code>title</code> and <code>h3</code> lines:
+<syntaxhighlight lang="html">
+[...]
+<title>GnuCash Report Prototype</title>
+[...]
+<h3>GnuCash Report Prototype</h3>
+[...]
+</syntaxhighlight>
+Next it is possible to add attributes to the body line.
+{| class="wikitable"
+|-
+|'''Note:''' You should read the following section for informational purposes only: Style sheets are now the preferred way to specify a document's presentation, the presentational attributes of BODY have been deprecated. ([{{URL:W3C}}TR/html401/struct/global.html#edef-BODY quoted from W3.org])
+(Currently in ''GnuCash'' the <code>bgcolor</code>-tag is default part of the <code>body</code>-tag.)
+|}
+The <code>body</code>-tag can be enhanced with attributes via the <code>gnc:html-document-set-style!</code> funtion. The general sytax:
+<syntaxhighlight lang="scheme">
+(gnc:html-document-set-style!
+    document                               ;; the reference to the current html-document
+    "body"                                 ;; specify the tag to add attributes to
+    'attribute (list "blabla" "balabala")  ;; first additional attribute
+    'attribute (list "nonstop" "nonsens")  ;; second additional attribute
+    'attribute (list "bgcolor" "#f6ffdb")  ;; third additional attribute
+    [...]                                  ;; further attributes
+)
+</syntaxhighlight>
+The example above lists some imaginary attributes to indicate that the attribute definition will be added to the <code>body</code>-tag without further validity check. Invalid attributes will appear in the ''HTML''-code but will have no visible effect on the document representation.
+The rest of the body is filled with ''HTML''-text by defintion of text objects, which gives the following structure
+<syntaxhighlight lang="html">
+<body bgcolor="#ffffff">
+<h3>[title]</h3>
+  [text object 1]
+  [text object 2]
+    .     .    .
+    .     .    .
+    .     .    .
+  [text object n]
+</body>
+</syntaxhighlight>
+whereas it does not matter if you define one or more text objects, you can put everything into one object or split it over several objects.
+In ''Scheme'' these objects are defined like
+<syntaxhighlight lang="scheme">
+(gnc:html-document-add-object!
+    document               ;; the overall HTML document defined above
+    (gnc:make-html-text    ;; a text object
+        [text 1]             ;; part 1 of the text
+        [text 2]             ;; part 2 of the text
+             .   .
+             .   .
+             .   .
+        [text m]             ;; part m of the text
+    )
+)
+</syntaxhighlight>
+Note the above structure is the definition of 1 text object, which consists of m (sub-)text elements.
-=== Loading the Report ===
+The text elements can be simple strings, or ''markup''-formatted. ''Markup''-commands are found in <tt>html-text.scm</tt>:
-There are two ways to load a report at startup of GnuCash: from a user account, or from the installation tree.  You will likely want to use the user account approach.
+<syntaxhighlight lang="scheme">
+gnc:html-markup-p        ;; markup for "paragraph"
+gnc:html-markup-tt       ;; markup for fixed font (type writer style)
+gnc:html-markup-em       ;; markup for "emphasis"
+gnc:html-markup-b        ;; markup for "bold"
+gnc:html-markup-i        ;; markup for "italic"
+gnc:html-markup-h1       ;; markup for headers on level 1
+gnc:html-markup-h2       ;; markup for headers on level 2
+gnc:html-markup-h3       ;; markup for headers on level 3
+gnc:html-markup-br       ;; markup for line "break" (no text)
+gnc:html-markup-hr       ;; markup for "horizontal line" (no text)
+gnc:html-markup-ul       ;; markup for "unsorted list" (bullet list)
+gnc:html-markup-anchor   ;; markup for hyperlinks
+gnc:html-markup-img      ;; markup for images
+</syntaxhighlight>
-==== Before you load the report ====
+To give you a basic idea, an example of simple text objects:
-* To avoid symbol definition conflicts with other reports, make sure your report code begins with a define-module statement: <pre>(define-module (gnucash report unique-report-name))</pre> like for example <pre>(define-module (gnucash report my-custom-invoice))</pre>
+<syntaxhighlight lang="scheme">
-* Make sure your report has a unique name (for GnuCash 2.2.x and before) or a unique id (GnuCash 2.3.x and later). These are set at the end of your code in a gnc:define-report statement. If you need some newly generated unique id, run the program gnucash-make-guid which is being installed by gnucash as well.
+(gnc:html-document-add-object!
+     document
+     (gnc:make-html-text
+        "some text"
+        "some other text"
+        (gnc:html-markup-br)
+        (gnc:html-markup-tt "tt text")
+        (gnc:html-markup-h1 "header1 text")
+        (gnc:html-markup "bla" "tirili flöt")
+        (gnc:html-markup "i" "italic text")
+    )
+)
+</syntaxhighlight>
-==== From a user account ====
+results in following ''HTML''-code
-In your home directory, edit <tt>~/.gnucash/config.user</tt> to add a line of the form:
+<syntaxhighlight lang="html">
+<body bgcolor="#f6ffdb">
+<h3>GnuCash Report Prototype</h3>
+some text some other text
+<br />
+<tt>tt text</tt>
+<h1>header1 text</h1>
+<bla>tirili flöt</bla>
+<i>italic text</i>
+</body>
+</syntaxhighlight>
+Note that it is possible to define new tags (here: "bla") if needed by using <code>gnc:html-markup</code>.
+Again: Take a good look at <tt>sample-report.scm</tt> and explore many more examples how to format ''HTML''-text.
+Examine:
 <pre>
-    (load "/path/to/my/personal/report.scm") ;; Linux
+html-scatter.scm
-    (load "X:\\path\\to\\my\\personal\\report.scm")  ;; Windows
+html-acct-table.scm
+html-piechart.scm
+html-table.scm
+html-linechart.scm
 </pre>
-Note that in Windows, double backslashes are required since backslash is a special character and must be escaped. In Windows, your GnuCash settings folder is usually <tt>C:\Users\YourName\.gnucash</tt>, or in Windows XP, <tt>C:\Documents and Settings\YourName\.gnucash</tt>
+to find out more about
+<syntaxhighlight lang="scheme">
+gnc:make-html-scatter
+gnc:make-html-acct-table
+gnc:make-html-barchart
+gnc:make-html-table
+gnc:make-html-linechart
+</syntaxhighlight>
+=== The <code>gnc:define-report</code> Statement ===
+If you want to follow the [[#Simple Proposal for Linux]] to setup a simple development environment then you need updates to this section only
+* once that you set up the development environment
+* once that your report is ready, fully tested, and shall become part of your standard reports
+And again, <tt>sample-report.scm</tt> already proposes how you should proceed in the latter case
+<pre>
+[...]
+to contribute your brand new, totally cool report, consult the mailing list "mailto:gnucash-devel@gnucash.org"
+[...]
+</pre>
+=== Barcharts ===
+The minimum definition of a bar chart report is shown in the following example based on a simple [[Tutorial for html-chart.scm|tutorial]] for generating charts using <tt>html-chart.scm</tt>. Before running, update <code>name</code>, <code>report-guid</code> and <code>menu-tip</code> values appropriately.
+<syntaxhighlight lang="scheme" highlight="13,70-72">
+;; -*-scheme-*-
+;; This is a minimum report definition in GnuCash.
+;; It illustrates the the minimum definitions needed to create
+;; a new GnuCash report.
+;; It will create an empty page with heading 'Prototype'.
+;; To be used as template.
+;; ------------------------------------------------------------------
+;; Top-level definitions
+;; ------------------------------------------------------------------
-'''Note:''' Without a leading '/', all paths are taken relative to ~/.gnucash
+(define-module (gnucash reports example prototype))
-Then '''restart''' GnuCash. You will have to do this '''every time''' you change a report.
+(use-modules (gnucash engine))
+(use-modules (gnucash utilities))
+(use-modules (gnucash core-utils))
+(use-modules (gnucash app-utils))
+(use-modules (gnucash report))
+(use-modules (gnucash html))
-''Thanks to [[User:DeanCording|DeanCording]] for clarifying the define-module/load bits''
+(debug-enable 'backtrace)
-==== From the installed report directory ====
+;; ------------------------------------------------------------------
-Alternatively, you can copy the report to the installed report directory.  Make sure you have included a module definition as shown above.  In gnucash-2.3.x or higher, all *.scm files from the directory guile-modules/gnucash/report/standard-reports/ will be loaded automatically. This applies ''only'' to the standard-reports/ sub-directory, not to any of the other directories with reports. Hence, the easiest way to have your report available to gnucash is to copy your *.scm file into that directory.
+;; Define the Options for this report
+;; ------------------------------------------------------------------
-Then '''restart''' GnuCash. You will have to do this '''every time''' you change the report definition file.
+(define (options-generator)
+  (gnc-new-optiondb))
+;; ------------------------------------------------------------------
+;; Render the HTML document
+;; ------------------------------------------------------------------
+(define (document-renderer report-obj)
+  (let (
+        (doc (gnc:make-html-document))
+        (chart (gnc:make-html-chart))
+       )
+       (gnc:html-chart-set-title! chart "title")
+       (gnc:html-chart-set-type! chart "bar")
+       (gnc:html-chart-set-width! chart '(pixels . 800))
+       (gnc:html-chart-set-height! chart '(pixels . 600))
+       (gnc:html-chart-set-y-axis-label! chart "yAxis")
+       (gnc:html-chart-set-data-labels! chart '("a" "b" "c"))
+       (gnc:html-chart-add-data-series! chart "series1" '(20 40 30) "red")
+       (gnc:html-chart-add-data-series! chart "series2" '(30 25 25) "green")
+       (gnc:html-chart-set! chart '(options chartArea backgroundColor) "wheat")
+       (gnc:html-document-add-object!
+        doc
+        (gnc:make-html-text
+         (gnc:html-markup-h3
+          (format #f (G_ "~a")
+               N_ "Demonstration"))))
+       (gnc:html-document-add-object! doc chart)
+       doc
+  )
+)
+;; ------------------------------------------------------------------
+;; Define the actual report
+;; ------------------------------------------------------------------
+(gnc:define-report
+ 'version 1
+ 'name (N_ "Prototype")
+ 'report-guid "<paste generated unique report id here>"
+ 'menu-tip (N_ "Unstable. Used for Testing.")
+ 'menu-path (list gnc:menuname-utility)
+ 'options-generator options-generator
+ 'renderer document-renderer)
+</syntaxhighlight>
+If you look at the HMTL source for this report after it is generated, you will see a line  with the <code><img></code> tag. The image for the report is encoded inline in a very long ASCII code string.
+<syntaxhighlight lang="html">
+<img src="data:image/png;base64,<very_long_ASCII_coded_string>" alt="Cannot display barchart"/> &nbsp;
+</syntaxhighlight>
+== The GnuCash API ==
+The GnuCash application programming interface ([{{URL:docs:API}} stable] or after the implementation of the first future feature [{{URL:docs:API|future}} future] branch) is quite intimidating, unfortunately. Luckily, for the reports, most of the stuff needed can be found in the scheme sources. Here some random examples of handy procedures  (paths shown refer to the location in a source tarball; might be copied into the location as above in your installation):
+* create a monetary object via <code>gnc:make-gnc-monetary</code> <tt>libgnucash/engine/gnc-numeric.scm</tt>
+* get the amount of a monetary object via <code>gnc:gnc-monetary-amount</code> <tt>libgnucash/engine/gnc-numeric.scm</tt>
+* get an account name via <code>xaccAccountGetName</code> <tt>libgnucash/engine/Account.cpp</tt>
+* create a commodity collector via <code>gnc:make-commodity-collector</code> <tt>gnucash/report/report-system/report-utilities.scm</tt>
+The mightiness of the API is huge. As of GnuCash 2.4.10, there were over 1000 GnuCash api calls that could be made from reports.
+It is by far too much to be documented in this Wiki-page.
+However, having a table at hand which includes the most common function calls is convenient especially at the start of digging into it.
+That is why following table is included in this chapter. The table does not purport to be exhaustive, nor even aim to be, but ''Scheme''-Report developers are invited to add to this table whenever they come across additions of general interest.
+{| class="wikitable"
+|-
+! scope="col"| Name
+! scope="col"| Source
+! scope="col"| Example
+! scope="col"| Comments
+|- style="vertical-align:top;"
+| style="white-space: nowrap;" | xaccAccountGetBalanceAsOfDate
+| style="white-space: nowrap;" | Account.cpp
+|
+| Returns the account balance as a number.
+Example:
+<syntaxhighlight lang="scheme">
+(xaccAccountGetBalanceAsOfDate acct date)
+</syntaxhighlight>
+|- style="vertical-align:top;"
+| gnc:html-table-append-row!
+| html-table.scm
+|
+| Appends a row to an HTML table.
+Note that <tt>row</tt> can be a list. If so, then each list element represents a column entry.
+Example:
+<syntaxhighlight lang="scheme">(gnc:html-table-append-row! table (list e1 e2 e3))</syntaxhighlight>
+will result in:
+<syntaxhighlight lang="html">
+<tr>
+<td>e1<td>
+<td>e2<td>
+<td>e3<td>
+</tr>
+</syntaxhighlight>
+Note that only simple lists are supported for. If you use nested lists as input, then the whole list contents of the nested lists will be displayed.
+|- style="vertical-align:top;"
+| gnc:gnc-numeric-denom
+| gnc-numeric.scm
+|
+| Returns the denominator part of a gnc-numeric record.
+|- style="vertical-align:top;"
+| gnc:gnc-numeric-num
+| gnc-numeric.scm
+|
+| Returns the numerator part of a gnc-numeric record.
+|- style="vertical-align:top;"
+| gnc-account-get-full-name
+| gnc_account_get_full_name() in Account.cpp
+| sample-report.scm
+| Returns the account name in the format
+<tt>ParentLevel1:ParentLevel2:...:AccountName</tt>
+To only get the <tt>AccountName</tt> use <tt>xaccAccountGetName</tt>
+|- style="vertical-align:top;"
+| xaccTransGetDate
+| xaccTransGetDate() in Transaction.c
+|
+| Returns the posting date of a transaction. Transactions are return e.g. by <tt>xaccSplitGetParent</tt>, see below. Note that this function will return the date as numerical value. If you need to have it human readable, you need to convert this numerical value into a date string, like so:
+<syntaxhighlight lang="scheme">
+(qof-print-date (xaccTransGetDate (xaccSplitGetParent split)))
+</syntaxhighlight>
+|- style="vertical-align:top;"
+| gnc-window-show-progress
+| gnc_window_show_progress() in gnc-window.c
+| report-utilities.scm
+| Used to forward processing progress information to the user. In <tt>report-utilities.scm</tt> this is wrapped in the routines:
+* <tt>gnc:report-starting
+* gnc:report-render-starting
+* gnc:report-percent-done
+* gnc:report-finished</tt>
+|- style="vertical-align:top;"
+| xaccAccountGetDescription
+| Account.cpp
+|
+| Returns the account description. To be used with the account as input parameter:
+<syntaxhighlight lang="scheme">(xaccAccountGetDescription acct)</syntaxhighlight>
+|- style="vertical-align:top;"
+| xaccAccountGetName
+| Account.cpp
+| sample-report.scm
+| Returns the account name. To get the full account name including parent names use <tt>gnc-account-get-full-name</tt>
+|- style="vertical-align:top;"
+| xaccAccountGetNotes
+| Account.cpp
+|
+| Returns the account notes. This is the text field that is found in the <tt>edit</tt> dialog of the accounts. To be used with the account as input parameter:
+<syntaxhighlight lang="scheme">(xaccAccountGetNotes acct)</syntaxhighlight>
+|- style="vertical-align:top;"
+| xaccAccountGetSplitList
+| Account.cpp
+| report-utilities.scm
+| Returns the the list of transactions in a given account. Note that in ''GnuCash'' each transaction is a split even if it is not a split transaction. A non-split transaction is a transaction consisting of a single split.
+To get the numerical value for the amount of splits in a list of accounts use <tt>gnc:accounts-count-splits</tt> defined in <tt>report-utilities.scm</tt>.
+The standard report <tt>cash-flow.scm</tt> makes use of this api.
+|- style="vertical-align:top;"
+| xaccAccountGetType
+| Account.cpp
+|
+| Returns the account type, which is the text field that is found in the <tt>edit</tt> dialog of the accounts. To be used with the account as input parameter <tt>(xaccAccountGetNotes acct)</tt>
+The following account types are available:
+<tt>
+* ACCT-TYPE-BANK
+* ACCT-TYPE-CASH
+* ACCT-TYPE-CREDIT
+* ACCT-TYPE-ASSET
+* ACCT-TYPE-LIABILITY
+* ACCT-TYPE-STOCK
+* ACCT-TYPE-MUTUAL
+* ACCT-TYPE-CURRENCY
+* ACCT-TYPE-INCOME
+* ACCT-TYPE-EXPENSE
+* ACCT-TYPE-EQUITY
+* ACCT-TYPE-CHECKING
+* ACCT-TYPE-SAVINGS
+* ACCT-TYPE-MONEYMRKT
+* ACCT-TYPE-RECEIVABLE
+* ACCT-TYPE-PAYABLE
+* ACCT-TYPE-CREDITLINE
+* ACCT-TYPE-TRADING</tt>
+|- style="vertical-align:top;"
+| xaccSplitGetAccount
+| Split.c
+|
+| Returns the account object that the split belongs to. To get the name from the returned account, use:
+<syntaxhighlight lang="scheme">(xaccAccountGetName (xaccSplitGetAccount split))</syntaxhighlight>
+|- style="vertical-align:top;"
+| xaccSplitGetCorrAccountName
+| Split.c
+|
+| Returns the account name at the other end of the split as a string.
+|- style="vertical-align:top;"
+| xaccSplitGetParent
+| Split.c
+|
+| Returns the parent transaction the split belongs to. See <tt>xaccTransGetDate</tt> for an example how to use it.
+|}
+=== Command line access to the API ===
+(Written Jan 2018)
+It is convenient to access the full API from a Guile Command-line for newbie report developers. This requires the developer is familiar with Linux, and can set up CMake, unit testing environments.
+The full GUI-generated reporting construct described above is important to test a custom report, however, is very inconvenient to explore the API.
+The preparation work involves:
+. Create a special unit test program in scheme, perhaps naming it test-server.scm - this shall reside in a convenient folder with other unit test files e.g. gnucash/report/standard-reports/test.
+<syntaxhighlight lang="scheme">
+(use-modules (gnucash gnc-module))
+(use-modules (gnucash app-utils))
+(use-modules (gnucash engine test test-extras))
+;; The following needed for Guile REPL
+(use-modules (system repl server))
+(define (run-test)
+  (run-server))
+;; The following needed for reports:
+(use-modules (gnucash report stylesheets))
+(use-modules (gnucash report report-system))
+(define constructor (record-constructor <report>))
+</syntaxhighlight>
+. Adding test-server.scm onto the CMakeFiles.txt in the same folder to enable compilation
+. Running make or ninja to generate the build directory
+. Running test-server.scm from the build directory by
+<syntaxhighlight lang="sh">cd build/gnucash/report/standard-reports/test
+/usr/bin/ctest -R test-server</syntaxhighlight>
+This will run the test server.
+. Switch to another terminal, run
+<syntaxhighlight lang="sh">nc localhost 37146 (the default guile port, upside down 37146 looks like guile...)
+</syntaxhighlight>
+This will now present a full Guile REPL prompt, with full access to the test-server.scm bindings as well as the Gnucash API. People familiar with emacs and the geiser package may also connect to the server by
+<code>M-x connect-to-guile</code>. Unfortunately so far, only the environment is loaded. I do not think the file-load mechanism is accessible to scheme, which is an inconvenience for testing reports.
+The developer can try:
+<syntaxhighlight lang="scheme">
+> ,apropos xacc [RET]
+(sw_engine): xaccTransEqual	#<procedure xaccTransEqual (_ _ _ _ _ _)>
+(sw_engine): xaccSplitGetCorrAccountCode	#<procedure xaccSplitGetCorrAccountCode (_)>
+(sw_engine): xaccAccountGetReconciledBalance	#<procedure xaccAccountGetReconciledBalance (_)>
+(sw_engine): xaccClearMarkDown	#<procedure xaccClearMarkDown (_ _)>
+(sw_engine): xaccSplitSetBaseValue	#<procedure xaccSplitSetBaseValue (_ _ _)>
+(sw_engine): xaccTransGetFirstAPARAcctSplit	#<procedure xaccTransGetFirstAP
+etc
+> ,apropos gnc- [RET]
+(sw_engine): gnc-monetary-list-delete-zeros	#<procedure gnc-monetary-list-delete-zeros (_)>
+(sw_engine): gnc-gdate-set-prev-fiscal-year-start	#<procedure gnc-gdate-set-prev-fiscal-year-start (_ _)>
+(sw_engine): gnc-quote-source-get-internal-name	#<procedure gnc-quote-source-get-internal-name (_)>
+(sw_engine): gnc-numeric-check	#<procedure gnc-numeric-check (_)>
+(sw_engine): gnc-timegm	#<procedure gnc-timegm (_)>
+(sw_engine): gnc-account-join-children	#<procedure gnc-account-join-c
+etc
+> ,bindings
+constructor             #<variable 55cae1534b70 value: #<procedure 55cae11ff080 at ice-9/boot-9.scm:1340:17 (a b c d e f g h)>>
+%module-public-interface #<variable 55cae0652da0 value: #<interface (guile-user) 55cae0638b40>>
+run-test                #<variable 55cae1534cc0 value: #<procedure run-test ()>>
+> (current-time)
+1515297631
+> (qof-print-date (current-time))
+"07/01/18"
+> (qof-date-format-set QOF-DATE-FORMAT-ISO)
+> (qof-print-date (current-time))
+"2018-01-07"
+</syntaxhighlight>
+=== Adding Menu Items ===
+The following example shows how to add a menu item from Scheme. The
+code adds the menu item <q>Tools › Scheme REPL</q> and the corresponding
+command starts a Scheme REPL in the tty.
+Installation:
+. Save the code somewhere in your file system like in <tt>~/hacking/gnucash/commands/repl.scm</tt>.
+. Add something like this to your ~/.config/gnucash/config-user.scm:
+<syntaxhighlight lang="scheme">
+(add-to-load-path "/home/helmut/hacking/gnucash/")
+(import (only (commands repl) register-repl-command))
+(register-repl-command)
+</syntaxhighlight>
+. Start GnuCash as usual.
+-----
+'''Code:'''
+<syntaxhighlight lang="scheme">
+(library (commands repl)
+  (export register-repl-command)
+  (import (rnrs base)
+	  (only (guile) format getenv resolve-module current-module
+		set-current-module save-module-excursion)
+	  (only (system repl repl) start-repl)
+	  (only (ice-9 readline) activate-readline write-history read-history)
+	  (only (gnucash gnome-utils) gnc-add-scm-extension)
+	  (only (gnucash gnome-utils gnc-menu-extensions) gnc:make-menu-item)
+	  (only (gnucash core-utils) G_ N_))
+  (define history-filename (format #f "~a/.gnucash_history" (getenv "HOME")))
-Alternatively (or for gnucash versions before 2.3.0), you can copy your *.scm file to one of the other report definition directories, but then you have to edit the appropriate Scheme file to register your report with the reporting system.  You will have to register the report in one of the following places, depending on which submenu you want it to appear.
+  (define previous-module #f)
-* Standard Reports: <tt>standard-reports.scm</tt>
+  (define (repl)
-* Business Reports: <tt>business-reports.scm</tt>
+    (save-module-excursion
-* Utility Reports: <tt>utility-reports.scm</tt>
+     (lambda ()
+       (set-current-module (or previous-module
+			       (begin
+				 (read-history history-filename)
+				 (activate-readline)
+				 (resolve-module '(guile-user)))))
+       (start-repl)
+       (set! previous-module (current-module))
+       (write-history history-filename)
+       (format #t "Goodbye~%"))))
-Then '''restart''' GnuCash. You will have to do this '''every time''' you change a report.
+  (define menuname-tools (N_ "Tools"))
-=== Debugging your report ===
+  (define (register-repl-command)
-There is not really a debugger available for guile, but you can have your code write debug messages to help you trace your code.
+    (gnc-add-scm-extension
+     (gnc:make-menu-item
+      "Scheme REPL"
+      "0155032a4b41443388f6cf8effc98169"
+      "Start a Scheme REPL in the tty"
+      (list menuname-tools)
+      (lambda (window)
+	(repl)))))
-* Start GnuCash like <pre>gnucash --debug --log gnc.scm=debug</pre> to enable debugging messages.
+  )
-* Add debugging messages with the <tt>(gnc:debug)</tt> variable, e.g. <tt>(gnc:debug "here I am")</tt>.
+</syntaxhighlight>
-* There are also (gnc:msg), (gnc:warn) and (gnc:error) functions; see src/scm/main.scm for more details.
-* Messages will be logged to /tmp/gnucash.trace by default, you can change this with --logto (try 'stderr' or 'stdout').
 == Other Resources ==
+One other way to create custom reports outside GnuCash, but directly from GnuCash data, is to use [[Ledger-CLI]].
 === Old GnuCash Report Information ===
 (may be very out of date)
-* [http://www.gnucash.org/docs/v1.6/C/x4501.html Version 1.6 report documentation]
+* [{{URL:www}}docs/v1.6/C/x4501.html Version 1.6 report documentation]
 * [[FAQ#Q:_I.27d_like_to_write_my_own_custom_reports._Where_should_I_start.3F]]
-* [http://www.gnucash.org/pipermail/gnucash-devel/2001-May/003493.html From the mailing list]
+* [{{URL:mail archive|devel}}2001-May/003493.html From the mailing list]
 === Learning Scheme ===
-* [http://groups.csail.mit.edu/mac/projects/scheme/ MIT Scheme Index]
+* [https://groups.csail.mit.edu/mac/projects/scheme/ MIT Scheme Index]
 * [http://download.plt-scheme.org/doc/360/html/t-y-scheme/t-y-scheme.html Teach Yourself Scheme in Fixnum Days]
 * [http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-1.html Structure and Interpretation of Computer Programs]
-* [http://www.htdp.org/  How to Design Programs]
+* [https://www.htdp.org/  How to Design Programs] and [https://www.ccs.neu.edu/home/matthias/HtDP2e/ HtDP, 2nd Edition]
-* Mastering Scheme is highly eased after reading [http://www.scheme.com/tspl2d/ The Scheme Progamming Language] by R. Kent Dybvig
+* [https://mitpress.mit.edu/books/little-schemer-fourth-edition The Little Schemer]
-* [http://www.gnu.org/software/guile/docs/docs.html Guile documentation]
+* Mastering Scheme is highly eased after reading [https://www.scheme.com/tspl4/ The Scheme Progamming Language] by R. Kent Dybvig
+* [{{URL:guile}}docs/docs.html Guile documentation]
+* Some guile code uses pattern matching. [http://ceaude.twoticketsplease.de/articles/an-introduction-to-lispy-pattern-matching.html An Introduction to Lispy Pattern Matching]