public static IASTNode Compile(SymbolTable symTable, object exp) { if (exp is string) { return new ASTNode_GetVar { address = SymbolTable.Lookup(symTable, (string)exp) }; } else if (exp is INumber) { return new ASTNode_Literal { value = exp }; } List<object> form = exp as List<object>; switch (form[0] as string) { case "quote": return new ASTNode_Literal { value = ListProcess.ListExpToPairExp(form[1]) }; case "if": return new ASTNode_If { predNode = Compile(symTable, form[1]), thenNode = Compile(symTable, form[2]), elseNode = Compile(symTable, form[3]) }; case "begin": return new ASTNode_Begin { nodes = form.Skip(1).Select(e => Compile(symTable, e)).ToList() }; case "lambda": { SymbolTable newSymTable = new SymbolTable(symTable); var formals = ((List<object>)form[1]).Cast<string>(); foreach (var name in formals) { newSymTable.DefineLocalSymbol(name); } List<string> defines = new List<string>(); ListProcess.FindDefinition(defines, (List<object>)form[2], 1); foreach (var name in defines) { newSymTable.DefineLocalSymbol(name); } IASTNode body = Compile(newSymTable, form[2]); var finder = new ASTNodeVisitor_FindFreeAddresses(body); return new ASTNode_Lambda { formalCount = ((List<object>)form[1]).Count, locals = formals.Concat(defines).ToList(), bodyNode = body, bodyFreeAddresses = finder.BodyFreeAddresses.ToList(), childrenFreeAddresses = finder.ChildrenFreeAddresses.ToList(), }; } case "define": case "set!": return new ASTNode_SetVar { address = SymbolTable.Lookup(symTable, (string)form[1]), rightNode = Compile(symTable, form[2]) }; default: return new ASTNode_Application { procedureNode = Compile(symTable, form[0]), actualNodes = form.Skip(1).Select(e => Compile(symTable, e)).ToList(), }; } }
public static object Lookup(SymbolTable table, string name) { if (table != null && table.mSym2Address.ContainsKey(name)) { return new LocalAddress { index = table.mSym2Address[name] }; } int envIndex = 0; while (table != null && !table.mSym2Address.ContainsKey(name)) { table = table.mPrevTable; ++envIndex; } if (table == null) { return DefineOrGetGlobalSymbol(name); } else { return new FreeAddress { envIndex = envIndex, index = table.mSym2Address[name] }; } }
public SymbolTable(SymbolTable prevTable) { mPrevTable = prevTable; }
private ASTInterpreter() { Utils.QueryPerformanceCounter(out sTimerStart); Utils.QueryPerformanceFrequency(out sTimerFreq); Dictionary <string, object> builtinVars = new Dictionary <string, object>() { { "true", true }, { "false", false }, { "else", true }, { "null", null }, }; Dictionary <string, Procedure> builtinProcedures = new Dictionary <string, Procedure>() { { "not", (args) => !(bool)args[0] }, { "identity", (args) => args[0] }, { "sqr", (args) => { var a = args[0] as INumber; return(a.Mul(a)); } }, { "+", (args) => ((INumber)args[0]).Add((INumber)args[1]) }, { "-", (args) => ((INumber)args[0]).Sub((INumber)args[1]) }, { "*", (args) => ((INumber)args[0]).Mul((INumber)args[1]) }, { "/", (args) => ((INumber)args[0]).Div((INumber)args[1]) }, { "quotient", (args) => ((INumber)args[0]).Div((INumber)args[1]).CastToInteger() }, { "remainder", (args) => ((INumber)args[0]).Mod((INumber)args[1]) }, { "=", (args) => (args[0].Equals(args[1])) }, { "<", (args) => (args[0] as IComparable).CompareTo(args[1]) < 0 }, { "<=", (args) => (args[0] as IComparable).CompareTo(args[1]) <= 0 }, { ">", (args) => (args[0] as IComparable).CompareTo(args[1]) > 0 }, { ">=", (args) => (args[0] as IComparable).CompareTo(args[1]) >= 0 }, { "eq?", (args) => object.ReferenceEquals(args[0], args[1]) }, { "cons", (args) => new Pair() { Car = args[0], Cdr = args[1] } }, { "car", (args) => ((Pair)args[0]).Car }, { "cdr", (args) => ((Pair)args[0]).Cdr }, { "drop", (args) => { Pair l = (Pair)args[0]; int n = ((NumberInteger)args[1]).value; for (; n > 0; --n) { l = (Pair)l.Cdr; } return(l); } }, { "length", (args) => { int n = 0; for (Pair l = (Pair)args[0]; l != null; ++n, l = (Pair)l.Cdr) { ; } return(Number.Create(n)); } }, { "append", (args) => { var l = ListProcess.PairToList((Pair)args[0]); l.InsertRange(l.Count, ListProcess.PairToList((Pair)args[1])); return(ListProcess.ListToPair(l)); } }, { "empty?", (args) => args[0] == null }, { "pretty-print", (args) => { ListProcess.PrintPairExp(args[0]); return(null); } }, { "display", (args) => { ListProcess.PrintListExp(ListProcess.PairExpToListExp(args[0])); return(null); } }, { "current-inexact-milliseconds", (args) => { long now; Utils.QueryPerformanceCounter(out now); return(Number.Create((decimal)(now - sTimerStart) * 1000 / sTimerFreq)); } }, { "exit", (args) => { Environment.Exit(0); return(null); } }, { "random", (args) => Number.Create(sRandom.Next(((NumberInteger)args[0]).value)) }, { "eval", (args) => Instance().Interpret(ListProcess.PairExpToListExp(args[0])) }, }; Env.ReserveGlobalVariables(builtinVars.Count + builtinProcedures.Count); foreach (KeyValuePair <string, object> kv in builtinVars) { Env.DefineBuiltin(SymbolTable.DefineOrGetGlobalSymbol(kv.Key), kv.Value); } foreach (KeyValuePair <string, Procedure> kv in builtinProcedures) { Env.DefineBuiltin(SymbolTable.DefineOrGetGlobalSymbol(kv.Key), kv.Value); } }