[erlang-questions] Function Dependency

Richard O'Keefe <>
Tue Aug 21 00:58:06 CEST 2012


On 21/08/2012, at 9:48 AM, Justin Calleja wrote:
> 
> Here's one instance that comes to mind with regards to wanting part of a function definition (i.e. just some of it's clauses):
> When implementing a gen_server you handle synchronous requests using handle_call/3. You might just want the implementation of handle_call/3 which deals with certain messages.

Yes, but that part
 - might be more than one clause
 - which need not be contiguous in the function
 - and some or all of them might be shared with the handling
   of other messages.

It is possible to deliberately construct a function as a
collection of clauses with small non-overlapping heads that
simply redirect to other functions, so that it would make
sense to extract part of _that_ function, and you would
do so *not* by extracting the clause but by simply picking
up the entire function that it delegates to.

That doesn't mean it makes sense to extract part of a
function that wasn't written to be treated that way.





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