Re^2: "last expression" quiz

You see, you are wondering about some stuff and learn a lot by side effect. Thank you very much for your answers.

With regard to the very "last expression", I guess we could conclude perlsub is not accurate there. It is true that some value is always returned, but in the subroutine

    sub foo { 1 for @_ }
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there are only TWO expressions, namely "1", and "@_". The "last expression" by definition should be one of them, but the return value is none of them.

Does anybody disagree with that conclusion?

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Re^3: "last expression" quiz by sauoq (Abbot) on Oct 20, 2005 at 09:38 UTC
Does anybody disagree with that conclusion? I certainly don't. An even better example: `sub foo { 1 for 1 }` [download] Now there's only one expression which always evaluates to the same thing, `1`, and yet the sub unintuitively returns `!1`. Certainly a patch is needed. Whether it should just be a doc patch to perlsub or different behavior should be forced, I don't know. -sauoq "My two cents aren't worth a dime.";	[reply] [d/l] [select]
Re^4: "last expression" quiz by halley (Prior) on Oct 20, 2005 at 14:08 UTC
Okay, I figured it was some peephole optimization thing. This is not what I would have predicted for deparse output, but it kind of makes sense. `$ perl -MO=Deparse -e 'sub foo { 1 for 1 } foo' sub foo { foreach $_ (1) { '???'; } } foo ; -e syntax OK` [download] The `'???'` appears for other constants, with which it would generate "useless use of constant in void context" warnings. This warning is suppressed for a few common constants. So I guess the opcode optimizer just forgets WHAT constant was there. -- `[ e d @ h a l l e y . c c ]`	[reply] [d/l] [select]