...why can't @foo be treated as an implicit list for DWIM purposes?
Because you asked Perl to treat it specially!

Think of it like this: when you say sub foo($), you're telling Perl to convert to a scalar the first arg of foo. When you say ``foo(@foo)'', you know that @foo has only one element (and therefore can assume you know what you mean), but perl doesn't. All perl looks at is the syntax of your code: an array is being used in a scalar context. So it gets converted to a scalar. Your "rule" for converting only works for 1-element lists; Perl's rule for converting an array to a scalar works for any size array.

It looks like another behaviour of Perl's conversion semantics that manages to confuse people.

In reply to Re: Function Prototype Context Conversion by ariels
in thread Function Prototype Context Conversion by tadman

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.