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