1 ! Copyright (C) 2009 John Benediktsson
2 ! See http://factorcode.org/license.txt for BSD license
4 USING: accessors assocs command-line io io.encodings.binary
5 io.files io.streams.string kernel math multiline namespaces
6 peg.ebnf prettyprint sequences ;
12 TUPLE: brainfuck pointer memory ;
14 : <brainfuck> ( -- brainfuck )
15 0 H{ } clone brainfuck boa ;
17 : get-memory ( brainfuck -- brainfuck value )
18 dup [ pointer>> ] [ memory>> ] bi at 0 or ;
20 : set-memory ( brainfuck value -- brainfuck )
21 over [ pointer>> ] [ memory>> ] bi set-at ;
23 : (+) ( brainfuck n -- brainfuck )
24 [ get-memory ] dip + 255 bitand set-memory ;
26 : (-) ( brainfuck n -- brainfuck )
27 [ get-memory ] dip - 255 bitand set-memory ;
29 : (.) ( brainfuck -- brainfuck )
32 : (,) ( brainfuck -- brainfuck )
35 : (>) ( brainfuck n -- brainfuck )
36 '[ _ + ] change-pointer ;
38 : (<) ( brainfuck n -- brainfuck )
39 '[ _ - ] change-pointer ;
41 : (#) ( brainfuck -- brainfuck )
43 [ "ptr=" write pointer>> pprint ]
44 [ ",mem=" write memory>> pprint nl ] bi ;
46 : compose-all ( seq -- quot )
47 [ ] [ compose ] reduce ;
49 EBNF: parse-brainfuck [=[
51 inc-ptr = (">")+ => [[ length '[ _ (>) ] ]]
52 dec-ptr = ("<")+ => [[ length '[ _ (<) ] ]]
53 inc-mem = ("+")+ => [[ length '[ _ (+) ] ]]
54 dec-mem = ("-")+ => [[ length '[ _ (-) ] ]]
55 output = "." => [[ [ (.) ] ]]
56 input = "," => [[ [ (,) ] ]]
57 debug = "#" => [[ [ (#) ] ]]
58 space = [ \t\n\r]+ => [[ [ ] ]]
59 unknown = (.) => [[ "Invalid input" throw ]]
61 ops = inc-ptr|dec-ptr|inc-mem|dec-mem|output|input|debug|space
62 loop = "[" {loop|ops}+ "]" => [[ second compose-all '[ [ get-memory zero? ] _ until ] ]]
64 code = (loop|ops|unknown)* => [[ compose-all ]]
70 MACRO: run-brainfuck ( code -- quot )
71 parse-brainfuck '[ <brainfuck> @ drop flush ] ;
73 : get-brainfuck ( code -- result )
74 [ run-brainfuck ] with-string-writer ; inline
78 : (run-brainfuck) ( code -- )
79 [ <brainfuck> ] dip parse-brainfuck call( x -- x ) drop flush ;
83 : brainfuck-main ( -- )
85 read-contents (run-brainfuck)
87 [ binary file-contents (run-brainfuck) ] each