Re^5: wantarray - surprise behaviour

I've seen this said before, but

P:\test>perl -MO=Deparse -e"@a = 1,2,3,4,5; print @a"
@a = 1, '???', '???', '???', '???';
print @a;
-e syntax OK

P:\test>perl -e"@a = 1,2,3,4,5; print @a"
1


P:\test>perl -MO=Deparse -e"@a = (1,2,3,4,5); print @a"
@a = (1, 2, 3, 4, 5);
print @a;
-e syntax OK

P:\test>perl -e"@a = (1,2,3,4,5); print @a"
12345
[download]

Empirically, that suggests that the parens are, at least in some cases, required to build a list.

Examine what is said, not who speaks.

"Efficiency is intelligent laziness." -David Dunham
"Think for yourself!" - Abigail
"Memory, processor, disk in that order on the hardware side. Algorithm, algorithm, algorithm on the code side." - tachyon

Comment on Re^5: wantarray - surprise behaviour Download Code

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Re^6: wantarray - surprise behaviour by Anonymous Monk on Sep 01, 2004 at 14:51 UTC
But they don't create lists. They are 'required' just as they are in some cases required to call a function correctly. That doesn't mean parens call functions. In the case you describe, parentheses are used for precedence: `perl -MO=Deparse,-p -e"@a = 1,2,3,4,5; print @a" ((@a = 1), '???', '???', '???', '???'); print(@a); -e syntax OK` [download] A list is still created - it's just not the list you want.	[reply] [d/l]
Re^7: wantarray - surprise behaviour by BrowserUk (Patriarch) on Sep 01, 2004 at 16:23 UTC
Which goes to demonstrate that saying that , and => builds lists is not enough. Just as parens are often required to clarify the programmers intent, so mentioning parens, and precedence is required to clarify the language's definition of a list. Examine what is said, not who speaks. "Efficiency is intelligent laziness." -David Dunham "Think for yourself!" - Abigail "Memory, processor, disk in that order on the hardware side. Algorithm, algorithm, algorithm on the code side." - tachyon	[reply]