[erlang-questions] Why do we need modules at all?
Tue May 24 18:05:01 CEST 2011
One thing I'd argue is that modules go some way to indicating the intent
of functions within (though maybe this can be replaced with good
Let's say we've got a sets module which happens to implement set data
structures as lists.
This sets module might define some generally useful list manipulation
functions, which others want to use.
However, the intent of those functions is to serve the sets module. If
the module owner wants to change one of the functions to be faster for
certain types of list and slower for others, it would make sense to do
so if it improved performance of the sets module as a whole.
If that function was in a global namespace of functions, it would need
metadata which indicated something like: "Although this is a general
list processing function, it is intended to support set data structures,
and as such may change internally to best serve this set of functions here."
I guess what I'm trying to say is that I can see the need for code
duplication when you've got:
X, a function intended to do X
Y, a function intended to do Y, which happens to be implemented as X
Though the code for them might look identical, there's the implied
contract that X will always do X, whereas Y could change at any time.
Modules (or namespaces in other languages) seem to be a reasonable way
of describing this intent/contract (albeit in vague terms, though most
modules seem to have an understandable purpose or theme).
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