note tirwhan <blockquote><i>And what would you (they) do if a module is subsequently needed in another subroutine in the same file?</i></blockquote> <p>Unless the other subroutine is in a different package it doesn't matter whether it also "use"s the module or not, it's loaded and will be available (I think [BrowserUK|you] are probably aware of this, just putting it in as clarification). See this example</p> <c> #!/usr/bin/perl use strict; use warnings; mainsub(); secsub(); thirdsub(); Frob::fourthsub(); sub mainsub { use Data::Dumper; } sub secsub { my $r = "secsub"; print Dumper $r; } sub thirdsub { use Data::Dumper; my $r = "thirdsub"; print Dumper $r; } package Frob; sub fourthsub { my $r = "thirdsub"; print Dumper $r; } </c> Output: <c> Name "Frob::Dumper" used only once: possible typo at useuse.pl line 31. $VAR1 = 'secsub'; $VAR1 = 'thirdsub'; print() on unopened filehandle Dumper at useuse.pl line 31. </c> <p>IMO there are several very good reasons not to put "use" into a subroutine (or other block) but rather at the top of a package:</p> <ul><li>It obfuscates which modules you are using, one has to hunt through the entire file to find out which modules are loaded.</li> <li>To make this more confusing, if the file contains multiple packages one needs to limit ones search to just that package, which requires thought instead of just editor-fu</li> <li>Programmers unfamiliar with the compile-time loading property of "use" might be surprised/confused about symbols from that module being available in other subroutines</li> <li>Conversely, programmers who come to rely on just sticking "use" anywhere in a file might be surprised that it's not available in a different package (this goes for putting "use" underneath the package declaration as well, but at least here the ordering gives a hint that the two are relevant to each other).</li></ul> <div class="pmsig"><div class="pmsig-237051"> <br><i>All dogma is stupid.</i> </div></div> 670475 670482