Re: looking for a good idiom: return this if this is true

The fact that this question has to be asked at all and the contortions necessary to answer it points to a deficiency in Perl's semantics. The following code

thatroutine() and return;
[download]

would be simple and effective were it not for the fact that a return with no argurments is equivalent to return undef (or return () in list context). By making the undef or () mandatory in order to clear the "last expression evaluated" this whole discussion could have been avoided.

Comment on Re: looking for a good idiom: return this if this is true Download Code

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Re^2: looking for a good idiom: return this if this is true by adamk (Chaplain) on Mar 07, 2005 at 13:55 UTC
Hardly a deficiancy... especially when return; doesn't return undef _OR_ (), it returns both undef _AND_ () at the same time (dependending on context of course). We would have to replace all existing return; with return wantarray ? () : undef; ugh...	[reply]
Re^3: looking for a good idiom: return this if this is true by merlyn (Sage) on Mar 07, 2005 at 15:20 UTC
It returns the equivalent of an empty list, which in a scalar context, is undef. `my $x = ();` [download] Sets $x to undef. -- Randal L. Schwartz, Perl hacker Be sure to read my standard disclaimer if this is a reply.	[reply] [d/l]
Re^2: looking for a good idiom: return this if this is true by DentArthurDent (Monk) on Mar 07, 2005 at 17:58 UTC
Doesn't the following bit of code work? It's only slightly more obtuse than what you propose. `thatroutine() and return 1;` [download] UPDATE: I just tested this to prevent ignorance, and it does in fact work. UPDATE AGAIN: Ah, I missed the point. My code does not return the value returned by thatroutine(). If there are no side effects I suppose you could do: `thatroutine() and return thatroutine();` [download] :-) ---- My mission: To boldy split infinitives that have never been split before!	[reply] [d/l] [select]
Re^2: looking for a good idiom: return this if this is true by anjoschu (Sexton) on Mar 07, 2005 at 16:27 UTC
This reminds me of how Applescript does it. When a sub is called in void context, the variable `result` gets assigned the return value. Sort of like this (pseudo): `thatroutine() and return @result;` [download] Sounds like a Perl 6 feature request...	[reply] [d/l]