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authorStavros Aronis <[email protected]>2010-05-30 23:42:34 +0300
committerHenrik Nord <[email protected]>2011-10-07 17:08:03 +0200
commit493262e2f024d3a0773b8a062c24de84b5cf21d5 (patch)
tree2b35e1b3e1f11be37609108dd62ae94baa513696
parent0edb6a4d2d76960846fd04ecce3aa00b3348691b (diff)
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Automatically generate 'behaviour_info' function from '-callback' attributes
'behaviour_info(callbacks)' is a special function that is defined in a module which describes a behaviour and returns a list of its callbacks. This function is now automatically generated using the '-callback' specs. An error is returned by lint if user defines both '-callback' attributes and the behaviour_info/1 function. If no type info is needed for a callback use a generic spec for it.
-rw-r--r--lib/compiler/src/sys_pre_expand.erl36
-rw-r--r--lib/stdlib/src/erl_lint.erl23
2 files changed, 56 insertions, 3 deletions
diff --git a/lib/compiler/src/sys_pre_expand.erl b/lib/compiler/src/sys_pre_expand.erl
index 249bd7a8e7..0fa1fea09f 100644
--- a/lib/compiler/src/sys_pre_expand.erl
+++ b/lib/compiler/src/sys_pre_expand.erl
@@ -43,6 +43,7 @@
mod_imports, %Module Imports
compile=[], %Compile flags
attributes=[], %Attributes
+ callbacks=[], %Callbacks
defined=[], %Defined functions
vcount=0, %Variable counter
func=[], %Current function
@@ -172,10 +173,41 @@ define_functions(Forms, #expand{defined=Predef}=St) ->
end, Predef, Forms),
St#expand{defined=ordsets:from_list(Fs)}.
-module_attrs(St) ->
- {[{attribute,Line,Name,Val} || {Name,Line,Val} <- St#expand.attributes],St}.
+module_attrs(#expand{attributes=Attributes}=St) ->
+ Attrs = [{attribute,Line,Name,Val} || {Name,Line,Val} <- Attributes],
+ Callbacks = [Callback || {_,_,callback,_}=Callback <- Attrs],
+ {Attrs,St#expand{callbacks=Callbacks}}.
module_predef_funcs(St) ->
+ {Mpf1,St1}=module_predef_func_beh_info(St),
+ {Mpf2,St2}=module_predef_funcs_mod_info(St1),
+ {Mpf1++Mpf2,St2}.
+
+module_predef_func_beh_info(#expand{callbacks=[]}=St) ->
+ {[], St};
+module_predef_func_beh_info(#expand{callbacks=Callbacks,defined=Defined,
+ exports=Exports}=St) ->
+ PreDef=[{behaviour_info,1}],
+ PreExp=PreDef,
+ {[gen_beh_info(Callbacks)],
+ St#expand{defined=union(from_list(PreDef), Defined),
+ exports=union(from_list(PreExp), Exports)}}.
+
+gen_beh_info(Callbacks) ->
+ List = make_list(Callbacks),
+ {function,0,behaviour_info,1,
+ [{clause,0,[{atom,0,callbacks}],[],
+ [List]}]}.
+
+make_list([]) -> {nil,0};
+make_list([{_,_,_,[{{Name,Arity},_}]}|Rest]) ->
+ {cons,0,
+ {tuple,0,
+ [{atom,0,Name},
+ {integer,0,Arity}]},
+ make_list(Rest)}.
+
+module_predef_funcs_mod_info(St) ->
PreDef = [{module_info,0},{module_info,1}],
PreExp = PreDef,
{[{function,0,module_info,0,
diff --git a/lib/stdlib/src/erl_lint.erl b/lib/stdlib/src/erl_lint.erl
index 0d8773ff0d..78b996d94b 100644
--- a/lib/stdlib/src/erl_lint.erl
+++ b/lib/stdlib/src/erl_lint.erl
@@ -319,6 +319,9 @@ format_error({undefined_behaviour_callbacks,Behaviour}) ->
format_error({ill_defined_behaviour_callbacks,Behaviour}) ->
io_lib:format("behaviour ~w callback functions erroneously defined",
[Behaviour]);
+format_error({behaviour_info, {_M,F,A}}) ->
+ io_lib:format("cannot define callback attibute for ~w/~w when "
+ "behaviour_info is defined",[F,A]);
%% --- types and specs ---
format_error({singleton_typevar, Name}) ->
io_lib:format("type variable ~w is only used once (is unbound)", [Name]);
@@ -845,7 +848,8 @@ post_traversal_check(Forms, St0) ->
StB = check_unused_types(Forms, StA),
StC = check_untyped_records(Forms, StB),
StD = check_on_load(StC),
- check_unused_records(Forms, StD).
+ StE = check_unused_records(Forms, StD),
+ check_callback_information(StE).
%% check_behaviour(State0) -> State
%% Check that the behaviour attribute is valid.
@@ -1144,6 +1148,23 @@ check_unused_records(Forms, St0) ->
St0
end.
+check_callback_information(#lint{callbacks = Callbacks,
+ defined = Defined} = State) ->
+ case gb_sets:is_member({behaviour_info,1}, Defined) of
+ false -> State;
+ true ->
+ case dict:size(Callbacks) of
+ 0 -> State;
+ _ ->
+ CallbacksList = dict:to_list(Callbacks),
+ FoldL =
+ fun({Fa,Line},St) ->
+ add_error(Line, {behaviour_info, Fa}, St)
+ end,
+ lists:foldl(FoldL, State, CallbacksList)
+ end
+ end.
+
%% For storing the import list we use the orddict module.
%% We know an empty set is [].