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{ "tags" : [], "draft" : null, "title" : "Perl Style: Never define "TRUE" and "FALSE"", "authors" : [ "tom-christiansen" ], "categories" : "programming-languages", "image" : null, "description" : null, "slug" : "/doc/FMTEYEWTK/style/slide13.html", "thumbnail" : null, "date" : "1998-01-01T00:00:00-08:00" }

  • The language understands booleans. Never define them yourself! This is terrible code:

         $TRUE  = (1 == 1);
     $FALSE = (0 == 1);

     if ( ($var =~ /pattern/ == $TRUE  ) { .... }
     if ( ($var =~ /pattern/ == $FALSE ) { .... }
     if ( ($var =~ /pattern/ eq $TRUE  ) { .... }
     if ( ($var =~ /pattern/ eq $FALSE ) { .... }

     sub getone { return "This string is true" }

     if ( getone() == $TRUE  ) { .... }
     if ( getone() == $FALSE ) { .... }
     if ( getone() eq $TRUE  ) { .... }
     if ( getone() eq $FALSE ) { .... }

  • Imagine the silliness of this progression, and stop at the first one.

         if (    getone() )                       { .... }                   
     if (    getone() == $TRUE  )             { .... }
     if (   (getone() == $TRUE) == $TRUE  )           { .... }
     if ( ( (getone() == $TRUE) == $TRUE) == $TRUE  ) { .... }

Forward to Embrace Pattern Matching
Back to Don't Overdo `?:'
Up to index

Copyright © 1998, Tom Christiansen All rights reserved.