IIRC the PBP advises to omit parens when unambiguously calling built-ins, because (and I agree) it removes extra-noise and improves readability. Thus, CL#1 is written as it was and it runs OK.

Then, looking at CL#2, I thought to omit a pair of parens -- see CL#3. I don't see anything becoming ambiguous, but Perl is confused -- see CL#4. And why the uniq imposes numeric context?

Also curious, if I'm explicitly imposing numeric context on sort (CL#5), Perl warns me 6 times, and not 5, as with CL#3.

>perl -lwe "sub x{@_} print sort x( qw( q w e r t y ))"
eqrtwy

>perl -MList::Util=uniq -lwe "print sort( uniq( qw( q w e r t y )))"
eqrtwy

>perl -MList::Util=uniq -lwe "print sort uniq( qw( q w e r t y ))"
Argument "w" isn't numeric in sort at -e line 1.
Argument "r" isn't numeric in sort at -e line 1.
Argument "y" isn't numeric in sort at -e line 1.
Argument "e" isn't numeric in sort at -e line 1.
Argument "t" isn't numeric in sort at -e line 1.
qwerty

>perl -MO=Deparse -MList::Util=uniq -lwe "print sort uniq( qw( q w e r
+ t y ))"
BEGIN { $^W = 1; }
BEGIN { $/ = "\n"; $\ = "\n"; }
use List::Util (split(/,/, 'uniq', 0));
print((sort uniq 'q', 'w', 'e', 'r', 't', 'y'));
-e syntax OK

>perl -lwe "print sort {$a <=> $b} qw( q w e r t y )"
Argument "q" isn't numeric in sort at -e line 1.
Argument "w" isn't numeric in sort at -e line 1.
Argument "e" isn't numeric in sort at -e line 1.
Argument "r" isn't numeric in sort at -e line 1.
Argument "t" isn't numeric in sort at -e line 1.
Argument "y" isn't numeric in sort at -e line 1.
qwerty

[download]

In reply to Perl parser gets confused with call to "sort" w/o parens by vr

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.