Execute Brain****/Elena
<lang elena>#define system.
- define system'routines.
- define extensions'text.
// --- Tape ---
- class BFTape
{
#field theArray. #field thePointer.
#constructor new &length:aLength [ thePointer := Integer new:0.
theArray := arrayControl new &length:aLength &each: n [ Integer new:0 ]. ]
#method bf_tape = $self.
#method append [ (theArray@thePointer) += 1. ] #method reduce [ (theArray@thePointer) -= 1. ] #method next [ thePointer += 1. ]
#method previous [ thePointer -= 1. ] #method input [ (theArray@thePointer) write &int:(console readChar). ] #method output [ console write:(CharValue new:(theArray@thePointer)). ]
#method run : aLoop [ control while:[ 0 < (theArray@thePointer) ] &do: [ aLoop eval:self ]. ] #method get = theArray@thePointer.
}
// --- LoopInterpreter ---
- class LoopInterpreter
{
#field theLoopBody. #field theTape. #constructor new &tape:aTape [ theTape := aTape. theLoopBody := String new. ] #method bf_tape = theTape bf_tape.
#method append [ theLoopBody += "+". ] #method reduce [ theLoopBody += "-". ] #method next [ theLoopBody += ">". ]
#method previous [ theLoopBody += "<". ] #method input [ theLoopBody += ",". ] #method output [ theLoopBody += ".". ] #method repeatUntil [ theTape run: aTape [ interpreter'Interpreter new:aTape eval:theLoopBody ]. ^ theTape. ]
}
// --- Interpreter ---
- class Interpreter
{
#field theTape.
#constructor new : aTape [ theTape := aTape. ]
#method eval : anObject [ $self eval::anObject. ] #method eval &literal:aLiteral [ control foreach:aLiteral &do:$self. ]
#method eval &char:aChar [ aChar => ">" ? [ theTape next ] "<" ? [ theTape previous ] "+" ? [ theTape append ] "-" ? [ theTape reduce ] "." ? [ theTape output. ] "," ? [ theTape input. ] "[" ? [ theTape := LoopInterpreter new &tape:theTape. ] "]" ? [ theTape := theTape repeatUntil. ]. ]
}
// --- Program ---
- symbol program =
[
('program'arguments length == 1)? [ console write:"Please provide the path to the file to interpret". #throw BreakException new. ]. textFileControl forEachLine:('program'arguments@1) &do:(Interpreter new:(BFTape new &length:1024)).
].</lang>