in reply to Re: Re: {} vs do{}
in thread {} vs do{}

Just keep in mind the important caveat that: 
  do { BLOCK } while ( COND );

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is NOT equivalent to: 
  while ( COND ) { BLOCK }

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In the first case, the code in BLOCK is executed once before checking the condition. This goes for until as well. However: 
  do { BLOCK } for ( LIST );

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is equivalent to: 
  for ( LIST ) { BLOCK }

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   MeowChow                                   
               s aamecha.s a..a\u$&owag.print

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Re: Re: Re: Re: {} vs do{}
by John M. Dlugosz (Monsignor) on Jul 04, 2001 at 23:14 UTC
    The condition at the end running once before the test is something I've long known, since the Pascal days. That for doesn't is not something I've thought about.

    $value= "global";

do { print "Inside block: $value\n" }
   for (my $value= 5;  $value < 7;  ++$value);

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    does not compile, so whether the loop variable is set first or later or what the scope is is moot. For the list form, 
    $_= 1;

do { print "Inside block: $_\n" }
   for (5..7);

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    It is intuative that it work the same way, one iteration per item in the list, and you can't use a variable, e.g. 
    do { print "Inside block: $value\n" }
   for my $value (5..7);

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    doesn't compile either. So variable scope issues are avoided.

    Interesting.

    —John

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