Last Updated: February 25, 2016
·
528
· nekrograve

Generate ETS parametrized match-spec from record definition

-module(match_spec_from_record).
-export([hooks_for_scope/2]).
-record(hooks, {
        scope :: atom(),
        pid   :: pid(),
        pre   :: mfa(),
        post  :: mfa()
    }).

hooks_field_match_spec(1, _Scope, _Hook)            -> hooks; 
hooks_field_match_spec(#hooks.scope, Scope, _Hook)  -> Scope;
hooks_field_match_spec(#hooks.post, _Scope, post)   -> '$1';
hooks_field_match_spec(#hooks.pre,  _Scope, pre)    -> '$1';
hooks_field_match_spec(_Fld, _Scope, _Hook)         -> '_'.

hooks_for_scope(Scope, Hook) ->
    S = record_info(size, hooks),
    V = [hooks_field_match_spec(Fi, Scope, Hook) 
            || Fi <- lists:seq(1, S)], 
    M = list_to_tuple(V),
    R = ets:match(Scope, M),
    [H || [H] <- R].