The ampersand is ambiguous and can be interpreted by perl as bitwise AND in certain contexts. Since it is not necessary, it is better to always omit the &.

Sounds profound, and it got you quite some XP. It should have been negative XP, because your conclusion is 100% wrong. If you you are afraid to get be bitten by the ambiguity you mention, you should avoid using bitwise and, not the sub-sigil. Because whenever perl has the option to parse an ampersand as a sub-sigil or as a bitwise and, it will parse it as the sub-sigil.

    $ perl -MO=Deparse,-p -e 'sub foo {} sub bar {} bar & foo()'
    sub foo {
    
    }
    sub bar {
    
    }
    bar(&foo());
    -e syntax OK
[download]

Someone using sub-sigils in the above case would have gotten the binary and parsing:

    perl -MO=Deparse,-p -e 'sub foo {} sub bar {} &bar & &foo()'
    sub foo {
    
    }
    sub bar {
    
    }
    (&bar & &foo());
[download]

So, you have two options to avoid this ambiguity: either avoid using binary and, or to always use the sub-sigil.

---

---

• Are you posting in the right place? Check out Where do I post X? to know for sure.
• Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:

  <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>

• Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
• Want more info? How to link or How to display code and escape characters are good places to start.