void ASTVisitor.Accept(NodeTry value)
{
Accept(value);
}
internal void Accept(NodeTry t)
{
// Disable scopes, we'll do them ourselves
if (t.body is NodeBlock)
(t.body as NodeBlock).createScope = false;
if (t.handler is NodeBlock)
(t.handler as NodeBlock).createScope = false;
uint stackSize = builder.StackCount;
// Start the exception handler
uint handler = builder.OpPushExH(0);
// Do things!
t.body.isResultRequired = t.isResultRequired;
t.body.inTailPosition = t.inTailPosition;
builder.StartScope();
t.body.Visit(this);
builder.EndScope();
// When we're done, skip the exception handling code
uint pass = builder.OpJump(0);
// This is where we'll go if we fail
builder.SetOpC(handler, builder.InsnCount);
// Begin our exception handling, which clears the stack to a certain point for us
builder.OpBeginExH(stackSize);
// Here, we have an exception! If we want it, assign it to our local var
builder.StartScope();
if (t.exceptionName != null)
{
uint local;
if (!builder.AddLocal(t.exceptionName, out local))
log.Error(t.location, "Duplicate local variable '{0}'.", t.exceptionName);
builder.OpStoreEx(local);
}
// Start the exception handling code
t.handler.isResultRequired = t.isResultRequired;
t.handler.inTailPosition = t.inTailPosition;
t.handler.Visit(this);
builder.EndScope();
// Here's where we jump if we pass everything
builder.SetOpC(pass, builder.InsnCount);
}
private Node ParseTry()
{
var expr = new NodeTry(Location);
Advance();
// what we're trying
if (!TokensRemain)
{
log.Error(expr.location, "Expected an expression for 'try' block, but the end of the file was reached.");
return expr;
}
expr.body = Expression();
Expect(CATCH, "Expected 'catch' block after try body.");
if (Check(OPEN_BRACE))
{
Advance();
string name;
ExpectIdentifier(out name, "Identifier expected as exception variable name.");
expr.exceptionName = name;
Expect(CLOSE_BRACE, "A close brace (')') is expected to surround exception variable name.");
}
// what we're using to handle issues
if (!TokensRemain)
{
log.Error(expr.location, "Expected an expression for 'catch' block, but the end of the file was reached.");
return expr;
}
expr.handler = Expression();
return expr;
}
