I set up a simple UNIVERSAL::VERSION method that allows me to search for an alternate versioned module ( e.g., one under development) instead of bailing out if the version number is too high. This works but not as cleanly as I'd like: I pull in the found module and the original. Is there any clean way to stop compilation of a given module without affecting the rest of the compile/run?

Related to this, I considered writing a true no by implementing a UNIVERSAL::unimport method that "unpollutes" the using module's namespace by removing aliased symbol table references. But it seems you can't undefine these. I tried code like this: 
    undef *{"${caller}::{$sym}"}{CODE};

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but that gives me the error:

Can't modify glob elem in undef operator

I saw code in the Monastary that claimed to do it like this: 
undef &{*{"${caller}::{$sym}"}{CODE}};

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But this doesn't seem correct to me -- they're undefining the function, not the symbol table reference to it, right? That seems supported by the different error I get:

Unable to create sub named ""

A note in Advanced Perl Programming seems to indicate that you can't undo aliased symbol table names -- only use local so they revert back to their old values automagically. But I can't force a local here since the no is an optional, separate piece from the use .

Any ideas? I haven't found anything yet I can't do somehow in Perl, but this one has me stumped.

In reply to version based compilation by steves

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