This is an excellent application for Deparse. The -p parameter to Deparse gives you nearly as many parenthesis as perl can give you, which is useful for explainging things. I was first exposed to this trick by Brother MeowChow when I asked how in hell his .sig worked. 

> perl -MO=Deparse,-p -e '$d, $e, $f = 1,2,3;'
-e syntax OK
($d, $e, ($f = 1), '???', '???');

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The latter arguments are thrown away because the '=' binds more tightly than the comma. If these were subroutines, they would have evaluated before being discarded. 
> perl -MO=Deparse,-p -e 'print(1),print(2),print("\n");'
-e syntax OK
(print(1), print(2), print("\n"));

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Note the parens around everything; to answer your question about why it evaluates all three terms, it is a list that gets discarded after evaluating its elements, which look like functions so they're evaluated as functions. 
> perl -MO=Deparse,-p -e 'print 1, print 2, print "\n";'
-e syntax OK
print(1, print(2, print("\n")));

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And your description was exactly right.

___
-DA
> perl -MPOSIX -le '$ENV{TZ}="EST";print ctime(1000000000)'
Sat Sep  8 20:46:40 2001

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In reply to Re: The Comma Operator by da
in thread The Comma Operator by dsb

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