RosettaCodeData/Task/Execute-Brain----/Seed7/execute-brain----.seed7
2014-04-02 16:56:35 +00:00

53 lines
1.8 KiB
Text

$ include "seed7_05.s7i";
const proc: brainF (in string: source, inout file: input, inout file: output) is func
local
var array char: memory is 100000 times '\0;';
var integer: dataPointer is 50000;
var integer: instructionPointer is 1;
var integer: nestingLevel is 0;
begin
while instructionPointer <= length(source) do
case source[instructionPointer] of
when {'>'}: incr(dataPointer);
when {'<'}: decr(dataPointer);
when {'+'}: incr(memory[dataPointer]);
when {'-'}: decr(memory[dataPointer]);
when {'.'}: write(output, memory[dataPointer]);
when {','}: memory[dataPointer] := getc(input);
when {'['}: # Forward if zero at dataPointer
if memory[dataPointer] = '\0;' then
nestingLevel := 1;
repeat
incr(instructionPointer);
case source[instructionPointer] of
when {'['}: incr(nestingLevel);
when {']'}: decr(nestingLevel);
end case;
until nestingLevel = 0;
end if;
when {']'}: # Backward if non-zero at dataPointer
if memory[dataPointer] <> '\0;' then
nestingLevel := 1;
repeat
decr(instructionPointer);
case source[instructionPointer] of
when {'['}: decr(nestingLevel);
when {']'}: incr(nestingLevel);
end case;
until nestingLevel = 0;
end if;
end case;
incr(instructionPointer);
end while;
end func;
const proc: brainF (in string: source) is func
begin
brainF(source, IN, OUT);
end func;
const proc: main is func
begin
brainF("++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>.");
end func;