RCBF/Forth

From Rosetta Code

A Brainf*** compiler written by Ian Osgood in Forth.

Contents 1 Usage 1.1 Compiling Brainf*** code 1.2 Running the compiled Brainf*** code 2 Source

[edit] Usage

Load the code your preferred Forth environment. The code will define the words :bf and :bf-file,

[edit] Compiling Brainf*** code

Let's say you have this sequence that prints a capital A:

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

You can compile it by using the :bf word:

:bf printA " ++++++[>+++++++++++<-]>-."

Your Brainf*** code is now compiled in your Forth environment as the word printA. If you want to use a different name, replace printA with your preferred name.

Larger BF programs may be loaded from a file instead of parsed from the interpreter:

:bf-file bottles bottles.bf

[edit] Running the compiled Brainf*** code

Assuming you used the word printA from the above example, you can execute your code by running the word:

printA

[edit] Source

Tested in: GNU Forth

\ brainfuck compiler

1024 constant size
: init  ( -- p *p ) here size erase  here 0 ;
: right ( p *p -- p+1 *p ) over c!  1+  dup c@ ;
: left  ( p *p -- p-1 *p ) over c!  1-  dup c@ ;		\ range check?

: compile-bf-char ( c -- )
  case
  [char] [ of postpone begin
              postpone dup
              postpone while  endof
  [char] ] of postpone repeat endof
  [char] + of postpone 1+     endof
  [char] - of postpone 1-     endof
  [char] > of postpone right  endof
  [char] < of postpone left   endof
  [char] , of postpone drop
              postpone key    endof
  [char] . of postpone dup
              postpone emit   endof
    \ ignore all other characters
  endcase ;

: compile-bf-string ( addr len -- )
  postpone init
  bounds do i c@ compile-bf-char loop
  postpone swap
  postpone c!
  postpone ;
;

: :bf ( name " bfcode" -- )
  :
  char parse    \ get string delimiter
  compile-bf-string ;

: :bf-file ( name file -- )
  :
  bl parse slurp-file
  compile-bf-string ;