private static void _parseParameters(CompilerState state)
{
for (var i = 0; i < state.Source.Parameters.Count; i++)
{
var id = state.Source.Parameters[i];
var sym = state.Symbols[id];
LocalBuilder local;
//Determine whether local variables for parameters have already been created and create them if necessary
switch (sym.Kind)
{
case SymbolKind.Local:
local = sym.Local ?? state.Il.DeclareLocal(typeof (PValue));
break;
case SymbolKind.LocalRef:
if (sym.Local == null)
{
local = state.Il.DeclareLocal(typeof (PVariable));
state.Il.Emit(OpCodes.Newobj, NewPVariableCtor);
state.EmitStoreLocal(local);
//PVariable objects already contain PValue.Null and need not be initialized if no
// argument has been passed.
}
else
{
local = sym.Local;
}
break;
default:
throw new PrexoniteException("Cannot create variable to represent symbol");
}
sym.Local = local;
var hasArg = state.Il.DefineLabel();
var end = state.Il.DefineLabel();
if (sym.Kind == SymbolKind.Local) // var = idx < len ? args[idx] : null;
{
//The closure below is only accessed once. The capture is therefore transparent.
// ReSharper disable AccessToModifiedClosure
state.EmitStorePValue
(
sym,
delegate
{
//(idx < argc) ? args[idx] : null;
state.EmitLdcI4(i);
state.EmitLoadLocal(state.ArgcLocal);
state.Il.Emit(OpCodes.Blt_S, hasArg);
state.EmitLoadNullAsPValue();
state.Il.Emit(OpCodes.Br_S, end);
state.Il.MarkLabel(hasArg);
state.EmitLoadArg(CompilerState.ParamArgsIndex);
state.EmitLdcI4(i);
state.Il.Emit(OpCodes.Ldelem_Ref);
state.Il.MarkLabel(end);
}
);
// ReSharper restore AccessToModifiedClosure
}
else // if(idx < len) var = args[idx];
{
state.EmitLdcI4(i);
state.EmitLoadLocal(state.ArgcLocal);
state.Il.Emit(OpCodes.Bge_S, end);
//The following closure is only accessed once. The capture is therefore transparent.
// ReSharper disable AccessToModifiedClosure
state.EmitStorePValue
(
sym,
delegate
{
state.EmitLoadArg(CompilerState.ParamArgsIndex);
state.EmitLdcI4(i);
state.Il.Emit(OpCodes.Ldelem_Ref);
});
// ReSharper restore AccessToModifiedClosure
state.Il.MarkLabel(end);
}
}
}