internal IOperand CompileForm([NotNull] IRoutineBuilder rb, [NotNull] ZilForm form, bool wantResult,
IVariable resultStorage)
{
using (DiagnosticContext.Push(form.SourceLine))
{
var unwrapped = form.Unwrap(Context);
if (!ReferenceEquals(unwrapped, form))
{
switch (unwrapped)
{
case ZilForm newForm:
form = newForm;
break;
default:
return(wantResult ? CompileAsOperand(rb, unwrapped, form.SourceLine, resultStorage) : null);
}
}
if (!(form.First is ZilAtom head))
{
Context.HandleError(new CompilerError(form, CompilerMessages.FORM_Must_Start_With_An_Atom));
return(wantResult ? Game.Zero : null);
}
// built-in statements handled by ZBuiltins
var zversion = Context.ZEnvironment.ZVersion;
Debug.Assert(form.Rest != null);
var argCount = form.Rest.Count();
if (wantResult)
{
// prefer the value version, then value+predicate, predicate, void
if (ZBuiltins.IsBuiltinValueCall(head.Text, zversion, argCount))
{
return(ZBuiltins.CompileValueCall(head.Text, this, rb, form, resultStorage));
}
if (ZBuiltins.IsBuiltinValuePredCall(head.Text, zversion, argCount))
{
var label1 = rb.DefineLabel();
resultStorage = resultStorage ?? rb.Stack;
ZBuiltins.CompileValuePredCall(head.Text, this, rb, form, resultStorage, label1, true);
rb.MarkLabel(label1);
return(resultStorage);
}
if (ZBuiltins.IsBuiltinPredCall(head.Text, zversion, argCount))
{
var label1 = rb.DefineLabel();
var label2 = rb.DefineLabel();
resultStorage = resultStorage ?? rb.Stack;
ZBuiltins.CompilePredCall(head.Text, this, rb, form, label1, true);
rb.EmitStore(resultStorage, Game.Zero);
rb.Branch(label2);
rb.MarkLabel(label1);
rb.EmitStore(resultStorage, Game.One);
rb.MarkLabel(label2);
return(resultStorage);
}
if (ZBuiltins.IsBuiltinVoidCall(head.Text, zversion, argCount))
{
ZBuiltins.CompileVoidCall(head.Text, this, rb, form);
return(Game.One);
}
}
else
{
// prefer the void version, then predicate, value, value+predicate
// (predicate saves a cleanup instruction)
if (ZBuiltins.IsBuiltinVoidCall(head.Text, zversion, argCount))
{
ZBuiltins.CompileVoidCall(head.Text, this, rb, form);
return(null);
}
if (ZBuiltins.IsBuiltinPredCall(head.Text, zversion, argCount))
{
var dummy = rb.DefineLabel();
ZBuiltins.CompilePredCall(head.Text, this, rb, form, dummy, true);
rb.MarkLabel(dummy);
return(null);
}
if (ZBuiltins.IsBuiltinValueCall(head.Text, zversion, argCount))
{
if (ZBuiltins.CompileValueCall(head.Text, this, rb, form, null) == rb.Stack)
{
rb.EmitPopStack();
}
return(null);
}
if (ZBuiltins.IsBuiltinValuePredCall(head.Text, zversion, argCount))
{
var label1 = rb.DefineLabel();
ZBuiltins.CompileValuePredCall(head.Text, this, rb, form, rb.Stack, label1, true);
rb.MarkLabel(label1);
rb.EmitPopStack();
return(null);
}
}
// routine calls
var obj = Context.GetZVal(Context.ZEnvironment.InternGlobalName(head));
while (obj is ZilConstant cnst)
{
obj = cnst.Value;
}
switch (obj)
{
case ZilRoutine rtn:
// check argument count
var args = form.Skip(1).ToArray();
if (args.Length < rtn.ArgSpec.MinArgCount ||
rtn.ArgSpec.MaxArgCount != null && args.Length > rtn.ArgSpec.MaxArgCount)
{
Context.HandleError(CompilerError.WrongArgCount(
rtn.Name?.ToString() ?? "<unnamed routine>",
new ArgCountRange(rtn.ArgSpec.MinArgCount, rtn.ArgSpec.MaxArgCount)));
return(wantResult ? Game.Zero : null);
}
// compile routine call
resultStorage = wantResult ? (resultStorage ?? rb.Stack) : null;
using (var argOperands = CompileOperands(rb, form.SourceLine, args))
{
rb.EmitCall(Routines[head], argOperands.AsArray(), resultStorage);
}
return(resultStorage);
case ZilFalse _:
// this always returns 0. we can eliminate the call if none of the arguments have side effects.
var argsWithSideEffects = form.Skip(1).Where(HasSideEffects).ToArray();
if (argsWithSideEffects.Length <= 0)
{
return(Game.Zero);
}
resultStorage = wantResult ? (resultStorage ?? rb.Stack) : null;
using (var argOperands = CompileOperands(rb, form.SourceLine, argsWithSideEffects))
{
var operands = argOperands.AsArray();
if (operands.Any(o => o == rb.Stack))
{
rb.EmitCall(Game.Zero, operands.Where(o => o == rb.Stack).ToArray(), resultStorage);
}
}
return(resultStorage);
default:
// unrecognized
if (!ZBuiltins.IsNearMatchBuiltin(head.Text, zversion, argCount, out var error))
{
error = new CompilerError(CompilerMessages.Unrecognized_0_1, "routine or instruction", head);
}
Context.HandleError(error);
return(wantResult ? Game.Zero : null);
}
}
}