in reply to Re: Operator precedence (void context)
in thread Operator precedence (or, I'm an idiot)

With the routine the $var may vary.

Even with: 

  sub rout {
       &blah;
        1;
  }

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there may be side effects.

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Re^3: Operator precedence (void context)
by tye (Sage) on Mar 07, 2003 at 22:32 UTC

    Of course there may be side effects. That is why you don't have to use -w. But there is no good reason to use grep and/or map solely for their side effects and there are good reasons to not do so. The warning would be: 

        Use of map/grep in void context, use foreach instead

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    If you have some perverse reason for doing such, then just turn off that warning. For people wanting help in catching simple errors, the warning will be useful.

                    - tye
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      As to how Perl can be improved. I agree with tye, map and grep should generate a warning in void context. I'd leave out the foreach recommendation except under diagnostics.

      In the same vein, Perl should have a wantvoid or wantbool operator so that the general case can be handled.

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