That also does a string eval, actually. See the _require sub in Module/Pluggable/Object.pm. Maybe I'm just barking up the wrong tree - I figured that something that's not uncommon (requiring a class at runtime, from a variable) could be done in a "best practices" sort of way. Apparently not. This seems strangely un-TIMTOWDI. | [reply] |
I was kinda suggesting the best practice was to avoid requireing dynamic class names completely, and address the problem at a higher level.
To answer your question directly, one can require either a class supplied as a bareword or a path. There isn't a way to require a class supplied in a scalar. In order to load a dynamically constructed class name, some use eval EXPR to do the former (e.g. Module::Pluggable), and some transform the class name into a path and use the latter (e.g. if). I have no idea why one cannot do require $class;.
| [reply]
[d/l]
[select] |
The second paragraph summarizes nicely the whole thread, but I cannot agree with the best practice you are suggesting which is don't use it IIUC.
eval-require is a common idiom for conditional loading of modules and there is a need for that.
From a language perspective a special "use" would be better like 'use any LIST' as the intent would be much clearer. Still you don't want "use base/use parent" wars^Wdiscussions for something simply expressed in an idiomatic but inelegant way. In the end I think low-level things like these should be made core pragmas
and (possibly) written in C, thriving for a minimalistic implementation.
cheers --stephan
| [reply] |