[erlang-questions] case and pattern matching
Tue Jul 10 12:40:38 CEST 2007
On 2007-07-10 12:08, Joel Reymont wrote:
> What do you do when two clauses in your case statement need to share
> the code? Do you create an anonymous function and reuse it?
> I really wish there was a way to combine patterns but I can't seem to
> find any. Consider the following bit of Mnesia code:
> init_indecies(Tab, Storage, PosList) ->
> case Storage of
> unknown ->
> s3_copies ->
> disc_only_copies ->
> init_disc_index(Tab, PosList);
> ram_copies ->
> make_ram_index(Tab, PosList);
> disc_copies ->
> make_ram_index(Tab, PosList)
> What I would like to do is join unknown and s3_copies or maybe
> ram_copies and disc_copies in a single pattern match like
> uknown | s3_copies -> ...
> Is this possible?
perhaps this is what you want:
case Storage of
unknown -> ignore;
Copies when (Copies =:= ram_copies) orelse (Copies =:= disc_copies) ->
Those were the days...
EPO guidelines 1978: "If the contribution to the known art resides
solely in a computer program then the subject matter is not
patentable in whatever manner it may be presented in the claims."
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