Re: Do multiple calls to 'use X' abuse the compiler?

use CGI::Application; imports the symbols from CGI::Application (if any) everytime it's executed.
use CGI::Application qw( );, on the other hand, is just a require that occurs at compile-time.
use base doesn't seem to have much overhead.

If I have 10 calls to 'use' in various modules (same namespace definition).. how much of a hit is that for the interpreter?

Benchmark it. It's the only way to know.

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Re^2: Do multiple calls to 'use X' abuse the compiler? by diotalevi (Canon) on Mar 02, 2008 at 02:18 UTC
Quadruple downvotes for saying "Benchmark it" to this question. The real answer is that every use() past the first is only a hash lookup. There's no abuse of the compiler and you should feel very safe in using the same thing from many places. Caveats are of course, that `$class->VERSION eq '...' or die "..."` and `$class->import(...)` are also possibly implicated but neither of those are compiler tasks and you ought to already know if you care about the overhead of each and whether you're invoking them. I can't imagine someone using CGI::Application is going to care about the additional cost of one cheap method call. ⠤⠤ ⠙⠊⠕⠞⠁⠇⠑⠧⠊	[reply] [d/l] [select]
Re^3: Do multiple calls to 'use X' abuse the compiler? by ikegami (Patriarch) on Mar 02, 2008 at 03:17 UTC
The real answer is that every use() past the first is only a hash lookup I said `use Module qw( );` is just a hash lookup, but `use Module;` isn't. Are you contradicting that? you ought to already know if you care about the overhead of each How? I heard `import` can be fairly costly. But to know for sure, one would been benchmark it. And whether or not he ought to know is not important. He asked so I answered.	[reply] [d/l] [select]
Re^4: Do multiple calls to 'use X' abuse the compiler? by diotalevi (Canon) on May 01, 2008 at 15:42 UTC
->import is frequently extremely cheap especially when it is just Exporter's. Modules are of course free to write their own import and may gmake them as expensive as they wish. ⠤⠤ ⠙⠊⠕⠞⠁⠇⠑⠧⠊	[reply]


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