public override void AddYieldTarget(YieldStatement ys, YieldTarget yt, CodeGen cg)
{
switch (state) {
case State.Try:
if (isPython24TryFinallyStmt)
cg.Context.AddError("cannot yield from try block with finally", ys);
else
stmt.AddTryYieldTarget(yt.FixForTryCatchFinally(cg));
break;
case State.Handler:
stmt.AddCatchYieldTarget(yt.FixForTryCatchFinally(cg));
break;
case State.Finally:
stmt.AddFinallyYieldTarget(yt.FixForTryCatchFinally(cg));
break;
case State.Else:
stmt.AddElseYieldTarget(yt.FixForTryCatchFinally(cg));
break;
}
ys.Label = yt.YieldContinuationTarget;
}
public override void AddYieldTarget(YieldStatement ys, YieldTarget yt, CodeGen cg)
{
stmt.AddYieldTarget(yt.FixForTryCatchFinally(cg));
ys.Label = yt.YieldContinuationTarget;
}
public override void PostWalk(YieldStatement node)
{
topYields[node.Index] = new YieldTarget(cg.DefineLabel());
if (tryBlocks.Count == 0) {
node.Label = topYields[node.Index].TopBranchTarget;
} else if (tryBlocks.Count == 1) {
ExceptionBlock eb = tryBlocks.Peek();
eb.AddYieldTarget(node, topYields[node.Index], cg);
} else {
bool isYieldInNestedWith = false;
foreach (ExceptionBlock e in tryBlocks) {
if (e is WithBlock)
isYieldInNestedWith = true;
}
if (Options.Python25 && isYieldInNestedWith)
cg.Context.AddError("yield in nested Try and/or With blocks", node);
else
cg.Context.AddError("yield in more than one try blocks", node);
}
}
public abstract void AddYieldTarget(YieldStatement ys, YieldTarget yt, CodeGen cg);
public void PostWalk(YieldStatement node)
{
PostProcess(node);
}
// YieldStatement
public bool Walk(YieldStatement node)
{
return Process(node);
}
public override bool Walk(YieldStatement node)
{
Emit(node); return false;
}
public virtual void PostWalk(YieldStatement node)
{
}
// YieldStatement
public virtual bool Walk(YieldStatement node)
{
return true;
}
private Statement ParseYieldStmt()
{
NextToken();
Location start = GetStart();
FunctionDefinition current = CurrentFunction;
int yieldId = 0;
if (current == null) {
ReportSyntaxError("'yield' outside function");
} else {
yieldId = current.YieldCount++;
}
Expression e = ParseTestListAsExpr(false);
YieldStatement ret = new YieldStatement(e, yieldId);
ret.SetLoc(GetExternal(), start, GetEnd());
return ret;
}
private Expression ParseGeneratorExpression(Expression test)
{
ForStatement root = ParseGenExprFor();
Statement current = root;
for (; ; ) {
if (PeekToken(Tokens.KeywordForToken)) {
current = NestGenExpr(current, ParseGenExprFor());
} else if (PeekToken(Tokens.KeywordIfToken)) {
current = NestGenExpr(current, ParseGenExprIf());
} else {
YieldStatement ys = new YieldStatement(test, 0);
ys.SetLoc(GetExternal(), test.Start, test.End);
NestGenExpr(current, ys);
break;
}
}
SymbolId fname = SymbolTable.StringToId("__gen_" + System.Threading.Interlocked.Increment(ref genexp_counter));
NameExpression pname = new NameExpression(SymbolTable.GeneratorParmName);
FunctionDefinition func = new FunctionDefinition(fname, new Expression[] { pname }, new Expression[] { }, FunctionAttributes.None, root, context.SourceFile);
func.YieldCount = 1;
func.SetLoc(GetExternal(), root.Start, GetEnd());
func.Header = root.End;
// Transform the root "for" statement
Expression outermost = root.List;
root.List = pname;
CallExpression gexp = FinishCallExpr(new NameExpression(fname), new Arg(outermost));
CallExpression iter = FinishCallExpr(new NameExpression(SymbolTable.Iter), new Arg(gexp));
GeneratorExpression ret = new GeneratorExpression(func, iter);
ret.SetLoc(GetExternal(), root.Start, GetEnd());
return ret;
}