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If I understand correctly, this optimization is done by the optimizer, working on already compiled code. This has a number of drawbacks:
  • The code must be compilable
  • Effort is spent compiling, that is thrown away later
  • Any BEGIN type code in there will have executed, so if you have a use in there, that module _will_ have been loaded.
To prove that last point:
if (0) { use strict; } print "INC = @{[keys %INC]}\n"; __END__ INC = strict.pm

Furthermore, to activate sections of code, no changes would need to be made to the program. It's all external with my solution. With your solution, you would have to export constant subs to all namespaces, a not so easy task and a definite pollution of namespace. Even though the optimizer takes away sections of code, there remains a coderef to the original constant in the package namespace. See this example:

sub FALSE () { 0 } if (FALSE) { use strict; } print "INC = @{[keys %INC]}\n"; print "FALSE exists\n" if exists &FALSE; __END__ INC = strict.pm FALSE exists

Hope this explains some of the reasons I had for doing it the way I did.

Liz


In reply to Re: Re: Debug code out of production systems by liz
in thread Debug code out of production systems by liz

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