// Compile a literal, symbol or expression that returns a typed value
// Return datatype to caller for type checking
DataTypes CompileValue(Type type, NodeListParser nlp)
{
Logger.WriteLine(4, "CompileValue {0} <{1}>", type, nlp);
// bracketed expression with arguments
if (nlp.IsSexpr)
{
var sexpr = nlp.GetSexprNode();
CompileSexpr(sexpr, nlp);
return(sexpr.DataType);
}
if (nlp.IsFunc)
{
// bare function no arguments
var sym = nlp.GetIdent().Sym as BuiltinSymbol;
CompileBuiltin(sym, NodeListParser.Null);
return(sym.DataType);
}
if (nlp.IsVariable)
{
var sym = nlp.GetIdent().Sym;
_gen.EmitLoadVar(sym);
return(sym.DataType);
}
if (nlp.IsAttribute || (nlp.IsList && nlp.CheckedHead.IsAttribute))
{
var handler = Symbols.Find("--attribute") as BuiltinSymbol;
if (handler != null)
{
CompileBuiltin(handler, nlp.GetParser());
}
else
{
nlp.Syntax("attribute not allowed here");
}
return(handler.DataType);
}
var func = _typeactiondict.SafeLookup(type);
if (func != null)
{
// direct lookup to get constant value
var value = func(type, nlp, this) as TypedValue;
_gen.EmitLoadValue(value);
return(value.DataType);
}
nlp.Unexpected("unknown type {0}", type);
return(DataTypes.Unknown);
}
// compile a prog block inside an existing scope
internal void CompileProg(NodeListParser nlp)
{
Logger.WriteLine(2, "CompileProg <{0}>", nlp);
// iterate over the action items in the prog block
while (!nlp.Done)
{
// value -- special handler
if (nlp.IsValue || nlp.IsValueCallable)
{
if (!CompileHandler("--value", nlp))
{
nlp.Syntax("bare value not allowed");
}
// callable function, call it
}
else if (nlp.IsCallable)
{
if (nlp.IsFunc && nlp.CurrentIdent.Sym.Keyword == Keywords.ELSE)
{
return; // sneaky!
}
var sexpr = nlp.GetSexprNode();
nlp.Expect(sexpr.DataType == DataTypes.Void, "void function");
CompileSexpr(sexpr, nlp);
// list -- special handler
}
else if (nlp.IsList)
{
var handler = Symbols.Find("--list") as BuiltinSymbol;
if (handler != null)
{
CompileBuiltin(handler, nlp.GetParser());
}
else
{
nlp.Unexpected("unknown function");
}
}
else
{
nlp.Expected("function call");
}
}
}
// these functions serve to ensure that symbols in nodes are defined as the right type
protected TypedValue DefSymbolValue(IdentNode node, TypedValue value)
{
if (node.Sym.IsValue && node.Sym.DataType == value.DataType)
{
return(node.Sym.Value);
}
Logger.WriteLine(3, "Getsym adding {0} value:{1} type:{2}", node.Sym.Name, value, value.DataType);
// will create new symbol and store in symbol table, so other nodes see the same thing
if (node.Sym.IsUndef)
{
Symbols.DefineValue(node.Name, value);
}
else if (value.GetType() == typeof(IdentValue) && node.Sym.Value is IdentValue)
{
; // any subclass will do for flag. TODO: reverse operation if flag defined first
}
else
{
_currentparser.Syntax("already defined {0} as type {1}", node.Name, node.Sym.DataType);
}
return(value);
}
// Compile an argument of given type
void CompileArg(Type type, NodeListParser nlp)
{
Logger.WriteLine(4, "CompileArg {0} <{1}>", type, nlp);
var func = _typeactiondict.SafeLookup(type);
// special for variable assignment and implicit definition
if (type == typeof(Variable))
{
var ident = nlp.GetIdent();
var datatype = DataTypes.Bool; // TODO: handle other types
if (ident.Sym.IsVariable)
{
nlp.Expect(ident.Sym.DataType == datatype, "variable of type {0}", datatype);
}
else if (ident.Sym.IsUndef)
{
Symbols.DefineVariable(ident.Name, datatype, BoolValue.False);
}
else
{
nlp.Expected("defined variable");
}
_gen.EmitRefVar(ident.Sym);
// handle these separately, could be variable or function
}
else if (type.IsSubclassOf(typeof(TypedValue)))
{
// TODO: type checking
CompileValue(type, nlp);
//var exptype = TypedValue.DataTypeDict.SafeLookup(type);
//var rettype = CompileValue(type, nlp);
//nlp.Expect(rettype == exptype, "value of type {0}", exptype);
// direct lookup gets special cases; else continue
}
else if (func != null)
{
var value = func(type, nlp, this);
_gen.EmitLoadValue(value);
// Array means parse a list of this type
}
else if (type.IsArray)
{
var nargs = 0;
for (var nlp2 = nlp.GetParser(); !nlp2.Done; nargs++)
{
CompileArg(type.GetElementType(), nlp2);
}
_gen.EmitToArray(type, nargs);
// List<> means parse a tail of this type
}
else if (type.IsGenericType && type.Name.StartsWith("List"))
{
var nargs = 0;
for (; !nlp.Done; ++nargs)
{
CompileArg(type.GetGenericArguments()[0], nlp);
}
_gen.EmitToList(type, nargs);
// Pair<> means parse a pair of arbitrary types
}
else if (type.IsGenericType && type.Name.StartsWith("Pair"))
{
var nlp2 = nlp.GetParser();
foreach (var subtype in type.GetGenericArguments())
{
CompileArg(subtype, nlp2);
}
_gen.EmitToPair(type);
// nested prog block
}
else if (type.IsSubclassOf(typeof(CodeBase)))
{
var info = Symbols.PredefScopeDict.First(kv => kv.Value.CodeType == type).Value;
CompileProg(info, nlp);
}
else if (type == typeof(PositionOrDirection))
{
CompilePositionOrDirection(nlp);
// function call on built in
}
else if (nlp.IsSexpr)
{
var sexpr = nlp.GetSexprNode();
var datatype = TypedValue.DataTypeDict.SafeLookup(type);
nlp.Expect(sexpr.DataType == datatype, "value of type {0}", datatype);
CompileBuiltin(sexpr.Sym as BuiltinSymbol, NodeListParser.Create(sexpr.Args, Symbols));
}
else
{
nlp.Syntax("unknown type {0}", type);
}
}
