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Re^3: Different behaviors between "while" and "map"

by betterworld (Curate)
on Dec 06, 2008 at 01:42 UTC ( #728454=note: print w/replies, xml ) Need Help??

in reply to Re^2: Different behaviors between "while" and "map"
in thread Different behaviors between "while" and "map"

It helps to know that the loop is expanded to:

while ($_ = <SOME_FILE_HANDLE>){ ... }

This shows that <...> is nothing more than a loop condition: the loop body is executed immediately after each evaluation of the <...> operator. This is how a while loop works.

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Re^4: Different behaviors between "while" and "map"
by JavaFan (Canon) on Dec 06, 2008 at 02:18 UTC
    Not for the last 12 years or so. It's expanded to
    while (defined ($_ = <SOME_FILE_HANDLE>)) { ... }

      Technically, you're both right, because

      while ($_ = <SOME_FILE_HANDLE>){ ... }
      is expanded to
      while (defined ($_ = <SOME_FILE_HANDLE>)) { ... }

      But all this is irrelevant. It's not the magical expansion of <> that causes the scalar context.

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