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https://github.com/matslina/awib

a brainfuck compiler written in brainfuck
https://github.com/matslina/awib

Last synced: 12 days ago
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a brainfuck compiler written in brainfuck

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README 

        
![example workflow](https://github.com/matslina/awib/actions/workflows/ci.yaml/badge.svg)



Awib is a brainfuck compiler entirely written in brainfuck.



- Awib implements several optimization strategies and its compiled

  output outperforms that of many other brainfuck compilers

- Awib is itself a 4-language polyglot and can be run/compiled

  as brainfuck, Tcl, C and bash

- Awib has 6 separate backends and is capable of

  compiling brainfuck source code to Linux executables (i386) and

  five programming languages: C, Tcl, Go, Ruby, Java and Rust



Usage

-----



Feed awib brainfuck source code as input and the compiled program

will be written as output.



Awib is a cross-compiler. The supported target platforms are

listed below. By default, the target "lang_c" is chosen.



To specify a target platform, insert a line on the form "@TARGET"

(without the quotation marks and with "TARGET" suitably replaced)

at the very beginning of the source code you wish to compile.

Awib will then produce output accordingly.



    386_linux - Linux executables for i386

    lang_c    - C code

    lang_ruby - Ruby code

    lang_go   - Go code

    lang_tcl  - Tcl code

    lang_java - Java code

    lang_rust - Rust code



For instance, the following input would produce an executable hello

world-program for Linux:



    @386_linux

    ++++++[->++++++++++++<]>.----[--<+++>]<-.+++++++..+++.[--->+<]>-----.--

    -[-<+++>]<.---[--->++++<]>-.+++.------.--------.-[---<+>]<.[--->+<]>-.



The following would produce a hello world-program in Ruby:



    @lang_ruby

    ++++++[->++++++++++++<]>.----[--<+++>]<-.+++++++..+++.[--->+<]>-----.--

    -[-<+++>]<.---[--->++++<]>-.+++.------.--------.-[---<+>]<.[--->+<]>-.



And this file would give you the hello world-program in C:



    @lang_c

    ++++++[->++++++++++++<]>.----[--<+++>]<-.+++++++..+++.[--->+<]>-----.--

    -[-<+++>]<.---[--->++++<]>-.+++.------.--------.-[---<+>]<.[--->+<]>-.



Optimizations

-------------



Awib is an optimizing compiler:



-  Sequences of '-','>','<' and '+' are contracted into single

   instructions. E.g. "----" is replaced with a single SUB(4).

-  Mutually cancelling instructions are reduced. E.g. "+++-->><"

   is equivalent to "+>" and is compiled accordingly.

-  Some common constructs are identified and replaced with single

   instructions. E.g. "[-]" is compiled into a single SET(0).

-  Loops known to never be entered are removed. This is the case

   for loops opened at the very beginning of a program (when all

   cells are 0) and loops opened immediately after the closing

   of another loop.

- Copy and multiplication loops are replaced with constant time

  operations. E.g. "[->>+++<+<]" is compiled into two RMUL(2, 3),

  RMUL(1,1)), SET(0)..



Requirements

------------



Awib will run smoothly in any brainfuck environment where:



-  Cells are 8-bit or larger

-  The read instruction ',' (comma) issued after end of

   input results in 0 being written OR -1 being written

   OR no change being made to the cell at all.



The vast majority of brainfuck environments meet these criteria.



Since awib is polyglot, it is also possible to compile and/or run awib

directly as C, tcl or bash. For instance, using gcc, the following

will build an executable file called awib from awib-0.2.b.



    $ cp awib-0.2.b awib-0.2.c

    $ gcc awib-0.2.c -o awib.tmp

    $ ./awib.tmp < awib-0.2.b > awib-0.2.c

    $ gcc -O2 awib-0.2.c -o awib



Using bash works fine, but is very very very slow:



    $ (echo "@386_linux"; cat awib.b) | bash awib.b > awib

    $ chmod +x awib



And tcl:



    $ (echo "@386_linux"; cat awib.b) | tclsh awib.b > awib

    $ chmod +x awib



Environment

-----------



Code compiled with awib will execute in an environment where:



-  Cells are 8-bit wrapping integers.

-  Issuing the read instruction ',' (comma) after

   end of input results in the current cell being

   left as is  (no-change on EOF).

-  At least 2^16-1 = 65535 cells are available.

-  Operating beyond the available memory, in either

   direction, results in undefined behaviour.



License

-------



    This program is free software: you can redistribute it and/or modify

    it under the terms of the GNU General Public License as published by

    the Free Software Foundation, either version 3 of the License, or

    (at your option) any later version.



    This program is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of

    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    GNU General Public License for more details.



    You should have received a copy of the GNU General Public License

    along with this program.  If not, see .



Mats Linander, 2014-09-14