#                        look
#                        behind  |------ $1 ------|
my $with_braces    = qr/ (?<!\\) ( \$ \{ (\w+) \} ) /x;
my $without_braces = qr/ (?<!\\) ( \$    (\w+)    ) /x;
#                                        |$2 |

[download]

Note that this use of lookbehind is generally not a safe way to look for an unescaped $, because generally when backslashes are used for escaping, they are also used for escaping backslashes themselves: \\$HOME would then be considered an escaped backslash followed by a replaceable variable reference.

In this context, it's less obvious what is correct since backslashes are not generally being used for escaping. As such, I'm not sure that the spec is coherent as a whole - it looks like there would be no way to express a string that should have one or more actual backslashes followed by a variable.

Hugo

In reply to Re^6: How to replace envs in path? by hv
in thread How to replace envs in path? by ovedpo15

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.