Re: effect of a label on following block
On Mon, 15 Nov 2010 19:34:46 +0300, Ellery Newcomer ellery-newco...@utulsa.edu wrote: My gut feeling is that the if statement's behavior is wrong and the while statement's is correct, but it could go either way. I agree, I think case with 'when' works as specs say. No need for a rationale for what can be adequately explained as a compiler bug There is still correct but unexpected behaviour. I found this on bugtracker http://d.puremagic.com/issues/show_bug.cgi?id=199 The rationale was I don't want to change this because it could break existing code, and there doesn't seem to be a compelling reason to do so. Well. :( Please to report to bugzilla I'll report about if/while inconsistency. -- Using Opera's revolutionary email client: http://www.opera.com/mail/
effect of a label on following block
Hello.
Consider this code
void main()
{
l:
{
int v;
}
v = 5; // ok, v is defined
}
As I understand from D's grammar this behaviour is not a bug as
LabeledStatement:
Identifier : NoScopeStatement
and NoScopeStatement in turn takes BlockStatement without creating new
scope.
It looks very unnatural for me though. Especially when label goes before
ThenStatement
if(1)
l1:{
int v;
}
v = 5;
it works as above, yet label after 'while'
while(1)
l1:{
int v;
}
v = 5; // error, v is undefined
has no such effect, even if ThenStatement is just another ScopeStatement.
I don't understand this difference. Any rationale behind this?
--
Using Opera's revolutionary email client: http://www.opera.com/mail/
Re: effect of a label on following block
My gut feeling is that the if statement's behavior is wrong and the while statement's is correct, but it could go either way. No need for a rationale for what can be adequately explained as a compiler bug (this is a downside of dmd - it trains you to think like this) It is curious, though, as it looks like both bodies get parsed the same way. Not sure what's going on. Please to report to bugzilla
Re: effect of a label on following block
poking around a little more and I really don't know what's going on.
fun piece of trivia though: while loops get rewritten to for loops, so
for(;;) l1 {
int v;
}
v = 4;
exhibits the same behavior as the while loop.
do loops seem to do the same thing as the if statement
On 11/15/2010 10:34 AM, Ellery Newcomer wrote:
My gut feeling is that the if statement's behavior is wrong and the
while statement's is correct, but it could go either way.
No need for a rationale for what can be adequately explained as a
compiler bug (this is a downside of dmd - it trains you to think like
this) It is curious, though, as it looks like both bodies get parsed the
same way. Not sure what's going on.
Please to report to bugzilla
Re: effect of a label on following block
Ellery Newcomer: No need for a rationale for what can be adequately explained as a compiler bug (this is a downside of dmd - it trains you to think like this) Or: Any sufficiently incomprehensible behaviour is indistinguishable from a DMD compiler bug :-) Bye, bearophile
Re: effect of a label on following block
On 15/11/2010 16:45, Ellery Newcomer wrote:
poking around a little more and I really don't know what's going on.
fun piece of trivia though: while loops get rewritten to for loops, so
for(;;) l1 {
int v;
}
v = 4;
exhibits the same behavior as the while loop.
do loops seem to do the same thing as the if statement
Eugh, that's fugly.
Labels shouldn't be allowed between keyword statements and their blocks,
it makes no sense in any circumstance.
--
My enormous talent is exceeded only by my outrageous laziness.
http://www.ssTk.co.uk
