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Programming language for symbolic computation with unusual combination of pattern matching features: Tree patterns, associative patterns and expressions embedded in patterns.



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Bracmat is software for exploration and transformation of uncharted and complex data. Bracmat employs a pattern matching technique that can handle string data (text) as well as structured data (XML, HTML, JSON, algebraic expressions, email, program code, ...).

The programming language construct for pattern matching supports associative pattern matching (known from regular expressions), and expression evaluation during pattern matching (comparable to guards in functional languages). The combination of pattern matching in (semi-)structured data with associative patterns that allow embedded expression evaluation is almost unique.

Bracmat is a good choice for tasks that require dynamic programming.

More than three hundred examples of Bracmat code can be found at Rosetta Code

This distribution contains the following directories and files:

  • Linux

    • bracmat

      64 bit statically linked executable for Linux (tested with Ubuntu 16.04, 18.04 and 20.04)

  • Python-module

    Python and Cython source code for creating a Python module 'prythat' so the Bracmat evaluator can be called from the Python programming language

    • build-launch.bat

      Windows batch file for creating a Bracmat module that can be included in Python programs. Contains two lines. The first line compiles and links the module, the second tests the result.


      Python program that demonstrates evaluation of Bracmat expressions, also call back to Python. Tests the prythat module.

    • prythat.pyx

      Cython source code that interfaces Python with Bracmat and vv.


      Makefile for buidling the module.

  • Windows

    • bracmat.exe

      32 bit executable for Windows

    • bracmat64.exe

      64 bit executable for Windows

  • doc

    • CLIN26-poster.pdf

      Poster presented at the 26th Meeting of Computational Linguistics in the Netherlands (CLIN26) in Amsterdam on December 18, 2015.

    • LT4DH14.pdf and LT4DH-2016-poster.pdf

      Paper and poster presented at the Language Technology four Digital Humanities workshop in Osaka, December 2016

    • NLPwithBracmat.pdf

      Tour through Bracmat for computational linguists.

    • bracmat-table.html

      The documentation in HTML format, automatically generated from the file 'help' and using an alternative lay-out with tables.

    • bracmat.html

      The documentation in HTML format, automatically generated from the file 'help'.

    • help

      The documentation in Bracmat format. (You have to run Bracmat and issue 'get$help' to see it properly.)

  • epoc

    • bracmat.SIS

      Installation program for Psion 5MX and Ericsson MC218 PDAs. This file is not always up to date.

  • java-JNI

    Java and C source code for creating a JNI (Java Native Interface) so the Bracmat evaluator can be called from the Java programming language.

    • java

    Java code


      Example program showing how to evaluate a Bracmat expression from within a Java program

    • dk

      • cst


        Java code that loads the Bracmat dynamic library.

    • bracmatdll.cpp, bracmatdll.h

      Source and header files that are needed for building the Windows version of a Bracmat JNI, which requires Bracmat to be in a dynamic linked library.

    • bracmattest.c

      Program source that links with a Bracmat dynamic library. For Linux.


      Linux script to create a Bracmat JNI. This file contains a comment that describes the steps to create a Bracmat JNI for the Windows platform using Visual C++.

    • dk_cst_bracmat.c, dk_cst_bracmat.h

      Source and header files that are needed for building a Bracmat JNI, which requires Bracmat to be in a dynamic linked library.

    • makeJNI.bat

      Batch file for Windows to create a Bracmat JNI. Should work with a number of versions of Microsoft's C-compiler.

  • macOS

    • bracmat

      executable for Apple computers

  • potu

    • many .c and .h files

    • Makefile

      There are two ways to compile and link the program, and both ways should be kept working in future development

      • All .c files (except potu.c) #included in potu.c, while making all .h files that contain function or global variable declarations ineffective. This way of compilation forces a (partial) order on the inclusion of the .c files. In general, the lower level functions are toward the top of the list, while the higher level functions are closer to the bottom of the list. This order mimics the order in the original bracmat.c file.

      • All .c files compiled separately and then linked. In this way, we ensure that each .c file includes all needed header files.

      The name 'potu', like 'bracmat', stems from the 1741 novel Nicolai Klimii Iter Subterraneum by Ludvig Holberg. Both are places on the planet Nazar that is inside the Earth. Nazar is inhabited by intelligent trees.

      The initial version of potu is functionally not different from bracmat.

  • safe

    • bracmatso.c

      Source file that includes bracmat.c after turning off functionality that we don't want in a JNI or Python module running in a production system: low level file manipulations, system() calls, and exit() which would bring the application container down.

  • src

    • Makefile

      Builds the standard edition of bracmat, a "safe" version of bracmat, a version for profiling, and a version for code coverage.

    • bracmat.c

      Most of the source code of the program.

    • bracmat.h

      An optional header file, if you want to compile Bracmat as a library.

    • json.c

      Source code that implements support for reading JSON-files

    • xml.c

      Source code that implements support for reading XML-files


      Script that configures DESCRIP.MMS


      OpenVMS makefile.

  • web

    All that is needed to create a version of Bracmat that runs in a browser.

    • bracmatJS.html

      Bracmat compiled to Javascript using emscripten, embedded in a single HTML-page. Nice for toy scripts, slow.

    • editbracmatjs.bra

      A Bracmat script that edits the output of the emscripten C-to-Javascript compiler and creates a HTML page containing Javascript embodying Bracmat.


      Linux batch file that runs emscripten and does some postprocessing, creating a Javascript version of Bracmat, bracmatJS.html. Requirement: emscripten 1.38.0 emcc and bracmat must be in PATH to run this script.

  • Changelog

    A document describing changes between versions.


    This file.


    The full text of the GNU public licence.


    Detailed explanation of how to use the wizzard project.bra to create a Bracmat program.

  • lex.bra

    Utility to spot unused variables and functions. It also tells you which variables are used outside their lexical scope. (Which is not an error, since Bracmat is dynamically scoped.)

  • pr-xml-utf-8.xml

    XML test file.

  • project.bra

    A tool to initialise a new Bracmat program. Usage: Read this file ( get'"project.bra" ) and answer the questions. The created program stub has a comment, a class for the program and a reread procedure that reads the file, renames the file to a backup and saves it, thereby nicely reformatting the code. (Most comments are lost!) Some editors discover that the file has been changed and propose to reread the file. In this way, the user doesn't need to bother about formatting. Cyclus: edit program, save from editor, reread in Bracmat, reload in editor, edit program.

  • uni.bra

    A utility that generates UNICODE-related tables from UnicodeData.txt ( These tables, which are also found in bracmat.c, have to be updated every few years, when UnicodeData.txt is updated. Conversion between lower and upper casing is based on these tables.

  • valid.bra

    A test suite. Whenever possible, one or more tests are added for every new functionality and every bug fix.


  • To start an interactive session


    • Quit by typing a closing parenthesis after the {?} prompt.
  • To run Bracmat in batch/mode

      bracmat parm1 parm2 ...
    • Bracmat evaluates each parameter, from left to right. When the last parameter is evaluated, bracmat exits.

    • Parameters can be enclosed in apostrophes (Linux, Mac) or quotes (Windows). These characters must be escaped with a backslash if they are part of a parameter

      bracmat $'out$Hello\\nWorld!&out\'"Here I am!\\nWhat about you?"'    (bash)
      bracmat "out$Hello\nWorld!&out'\"Here I am!\nWhat about you?\""    (Windows)

      Notice the $ in front of the Linux parameter. This is a bash extension that makes it possible to escape apostrophes. You should see this output:

      Here I am!
      What about you?

      In Linux, enclosing parameters in apostrophes or quotes is not necessary if you are willing to escape more characters. For example, this works:

      bracmat out\'Hello\&out\$world    (bash)

      On Windows, escaping is not possible in every case.

    • At least the first parameter must be a valid bracmat expression, appropriately quoted and 'escaped' to pass unscathed through the shell's own parameter evaluation mechanism.


You can download Bracmat from GitHub.

mkdir bracmat
cd bracmat
git init
git remote add origin
git pull origin master
cd ..


The Bracmat source code has no other dependencies than what is provided by Standard C. Building bracmat from source is extremely simple, e.g.:

gcc bracmat.c xml.c json.c

You can also use the Makefile, which is in the src directory.

Bracmat has been compiled and run on the following platforms:

  • Windows
    • All versions, compiled with 32 bit VC 6.0 and newer, BCC 5.02, tcc.
    • A 16 bit version existed until version 2.8
    • Bracmat can be compiled to 64 bits. This gives faster multiplication of very large numbers.
  • RISC-OS (Norcroft C ver 3)
  • EPOC 5 (Psion 5mx, Ericsson MC218: gcc)
  • HP-UNIX (gcc, cc)
  • Solaris (gcc)
  • Linux (gcc)
  • macOS (xcode, gcc)

If you have plans to run Bracmat from Python, you need Python and Cython besides a C-compiler. The software has been tested on Windows 10, 64 bit, using Cython version 0.28.2 and Python 3.6.3.


The file valid.bra contains enough tests to get in all corners of the source code, except those that lead to a controled exit condition.

For each error correction and for each new or changed feature a test must be added to valid.bra.

The testsuite valid.bra can also be used to find out how things can be programmed, although there is no good way to quickly search for what you are looking for.

usage: start Bracmat in interactve mode and write


What others say


this programming language Bracmat

& (   !table:? (!country.?len) ?
   & :?N
   & ( @( !arg
        :   ?
            ( %@?c ?
            & ( !c:#
              |   !c:~<A:~>Z
                & asc$!c+-1*asc$A+10:?c
                & 1+!len:?len
              | !c:" "&:?c
            & !N !c:?N
            & ~
beats Perl in terms of line noise

The code cited in this citation can be found in full length here: