factor/extra/brainfuck/brainfuck-docs.factor

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! Copyright (C) 2009 John Benediktsson
! See http://factorcode.org/license.txt for BSD license
USING: help.syntax help.markup brainfuck strings ;
IN: brainfuck
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HELP: run-brainfuck
{ $values { "code" string } }
{ $description
"A brainfuck program is a sequence of eight commands that are "
"executed sequentially. An instruction pointer begins at the first "
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"command, and each command is executed until the program terminates "
"when the instruction pointer moves beyond the last command.\n"
"\n"
"The eight language commands, each consisting of a single character, "
"are the following:\n"
{ $table
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{ { $strong "Character" } { $strong "Meaning" } }
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{ ">" "increment the data pointer (to point to the next cell to the right)." }
{ "<" "decrement the data pointer (to point to the next cell to the left)." }
{ "+" "increment (increase by one) the byte at the data pointer." }
{ "-" "decrement (decrease by one) the byte at the data pointer." }
{ "." "output the value of the byte at the data pointer." }
{ "," "accept one byte of input, storing its value in the byte at the data pointer." }
{ "[" "if the byte at the data pointer is zero, then instead of moving the instruction pointer forward to the next command, jump it forward to the command after the matching ] command*." }
{ "]" "if the byte at the data pointer is nonzero, then instead of moving the instruction pointer forward to the next command, jump it back to the command after the matching [ command*." }
}
"\n"
"Brainfuck programs can be translated into C using the following "
"substitutions, assuming ptr is of type unsigned char* and has been "
"initialized to point to an array of zeroed bytes:\n"
{ $table
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{ { $strong "Character" } { $strong "C equivalent" } }
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{ ">" "++ptr;" }
{ "<" "--ptr;" }
{ "+" "++*ptr;" }
{ "-" "--*ptr;" }
{ "." "putchar(*ptr);" }
{ "," "*ptr=getchar();" }
{ "[" "while (*ptr) {" }
{ "]" "}" }
}
} ;
HELP: get-brainfuck
{ $values { "code" string } { "result" string } }
{ $description "Returns the output from a brainfuck program as a result string." }
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{ $see-also run-brainfuck } ;