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Yabasic - A simple Basic interpreter for Unix and Windows.

Yabasic is a traditional basic-interpreter. It comes with goto and various loops and allows to define subroutines and libraries. It does simple graphics and printing. Yabasic can call out to libraries written in C and allows to create standalone programs. Yabasic runs under Unix and Windows and has a comprehensive documentation; it is small, simple, open-source and free.

If you want to write programs for yabasic, see for documentation.

If you want to modify yabasic itself and participate in its development, read below. The various files in subdirectories may contain some hints too.

A short overview on changing yabasic can be found at

Table of Content

The three top-level directories

Read below for an overview; some directories may contain their own with more details.

An additional top-level directory ‘products’ is created for the installable artifacts, which are created during the various build steps.

Directory ‘unix’

Here are most of the c-sources of yabasic as well as the input files for flex and bison, which describe yabasics grammer.

Also find the documentation, which is written in docbook-xml and transformed into html or man.

Directory ‘windows’

The build process uses the c-sources from the unix-directory, so here you will only find the sources for the windows-specific setup-program.

Directory ‘web’

The html-Files and erb-templates for

Building a new version of the website (by typing ‘rake’) is tested under windows (wsl), but should be workable under unix too.

Building Yabasic

Building under Unix

The simple and most common case: Building yabasic ‘as is’

This builds from the tar-ball available at or from

If you just want to build yabasic from the sources, but do not want to modify yabasic (e.g. by adding new commands) the procedure is fairly simple: Just go to and download the latest tar-file with sources, e.g. yabasic-2.90.2.tar.gz (as of this writing) and follow the instructions given on the download-page (essentially it is the usual configure and make).

As tools you will need make, a c-compiler, various libraries and header files (e.g. curses and x11, libffi is optional). Let the configure-process be your guide; it will barf on anything missing.

Please note, that you not need are the Autotools (autoconf, automake).

Finally note, that this building process does not involve cloning the github-repo (as you might have already done, when reading this).

The complex case: Changing yabasic and building it

This builds from the repo available at

There are some reasons, for which you may want to modify yabasic: E.g. change the grammar, add commands, build on exotic platforms, change the documentation; see for some more hints.

To build after such modifications, you will probably need more tools and experience than in the simple case above (but still feel free to contact me for any Problems).

Additional tools needed are: autoconf, automake, bison, flex, ruby.

As you probably have different versions of the Autotools than the maintainer, you probably need to do this:

  • automake –add-missing ## may give errors, but never mind
  • autoreconf

After that you may do the usual

  • ./configure
  • make

This will create a binary named “yabasic”

If want to build rpms and and deb-packages and run additional tests (which is scripted in a ruby Rakefile), you will need to

  • install ruby (if not already present on your system)
  • rake

The invocation of rake also moves the artefacts into the folder /work/yabasic/prodcts. If you have a machine with both linux and windows, this folder can be shared between both operating systems.

Building under Windows

Yabasic is be compiled with Visual Studio 2019, which can be installed free of charge.

All steps are automated with rake (ruby make); so typically you just need to invoke rake, which e.g. invokes the Visual Studio C-Compiler in turn.

Notes for the maintainer of yabasic

To update the table of content for this file, invoke ‘toc-org-insert-toc’.

To build yabasic both under Unix and Windows and to update the website, go through the steps below. The process is mostly automated, only asking for confirmation at certain key-points. Depending on your changes and desired products, you may be able to skip certain steps.

(Type “rake h” to read this text again from within any directory)

All steps are done from within wsl (windows subsystem for linux), only the directory changes.

  • Implement some features, fix some bugs, write tests, improve the docu; the files for nearly all of the features of yabasic can be found in directory unix/lang.
  • In directory unix/lang:
    • Edit to increment the version of yabasic
    • Document changes in NEWS
    • do rake; this does:
      • Run tests
      • Create tar, rpm and deb
  • In directory windows:
    • do rake; this does:
      • Build windows executable
      • Create setup.exe and zip-files (which will ask for admin priveleges)
  • In directory web:
    • do rake; this does:
      • Create new git tag and use the content of NEWS as the message
      • Upload everything to
  • Maybe submit new version to symantec and microsoft virus detection


Yabasic - A simple Basic interpreter for Unix and Windows







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