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authorHans Bolinder <[email protected]>2014-04-15 09:38:41 +0200
committerHans Bolinder <[email protected]>2014-04-28 11:56:26 +0200
commit146260727638e8a477aeda7828364ce45dc506a0 (patch)
treec54b396192cb875eea1c474baff18c136473b95c /lib/compiler/src
parent3be1dc100140139b2542cd327cf4f8453d43aca1 (diff)
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Introduce the attribute -optional_callbacks in the context of behaviours
Diffstat (limited to 'lib/compiler/src')
-rw-r--r--lib/compiler/src/sys_pre_expand.erl42
1 files changed, 36 insertions, 6 deletions
diff --git a/lib/compiler/src/sys_pre_expand.erl b/lib/compiler/src/sys_pre_expand.erl
index 761ae8409c..6410b73941 100644
--- a/lib/compiler/src/sys_pre_expand.erl
+++ b/lib/compiler/src/sys_pre_expand.erl
@@ -1,7 +1,7 @@
%%
%% %CopyrightBegin%
%%
-%% Copyright Ericsson AB 1996-2012. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2014. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
@@ -33,12 +33,15 @@
-include("../include/erl_bits.hrl").
+-type fa() :: {atom(), arity()}.
+
-record(expand, {module=[], %Module name
exports=[], %Exports
imports=[], %Imports
compile=[], %Compile flags
attributes=[], %Attributes
callbacks=[], %Callbacks
+ optional_callbacks=[] :: [fa()], %Optional callbacks
defined, %Defined functions (gb_set)
vcount=0, %Variable counter
func=[], %Current function
@@ -99,7 +102,21 @@ define_functions(Forms, #expand{defined=Predef}=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}}.
+ OptionalCallbacks = get_optional_callbacks(Attrs),
+ {Attrs,St#expand{callbacks=Callbacks,
+ optional_callbacks=OptionalCallbacks}}.
+
+get_optional_callbacks(Attrs) ->
+ L = [O ||
+ {attribute, _, optional_callbacks, O} <- Attrs,
+ is_fa_list(O)],
+ lists:append(L).
+
+is_fa_list([{FuncName, Arity}|L])
+ when is_atom(FuncName), is_integer(Arity), Arity >= 0 ->
+ is_fa_list(L);
+is_fa_list([]) -> true;
+is_fa_list(_) -> false.
module_predef_funcs(St) ->
{Mpf1,St1}=module_predef_func_beh_info(St),
@@ -108,19 +125,24 @@ module_predef_funcs(St) ->
module_predef_func_beh_info(#expand{callbacks=[]}=St) ->
{[], St};
-module_predef_func_beh_info(#expand{callbacks=Callbacks,defined=Defined,
+module_predef_func_beh_info(#expand{callbacks=Callbacks,
+ optional_callbacks=OptionalCallbacks,
+ defined=Defined,
exports=Exports}=St) ->
PreDef=[{behaviour_info,1}],
PreExp=PreDef,
- {[gen_beh_info(Callbacks)],
+ {[gen_beh_info(Callbacks, OptionalCallbacks)],
St#expand{defined=gb_sets:union(gb_sets:from_list(PreDef), Defined),
exports=union(from_list(PreExp), Exports)}}.
-gen_beh_info(Callbacks) ->
+gen_beh_info(Callbacks, OptionalCallbacks) ->
List = make_list(Callbacks),
+ OptionalList = make_optional_list(OptionalCallbacks),
{function,0,behaviour_info,1,
[{clause,0,[{atom,0,callbacks}],[],
- [List]}]}.
+ [List]},
+ {clause,0,[{atom,0,optional_callbacks}],[],
+ [OptionalList]}]}.
make_list([]) -> {nil,0};
make_list([{_,_,_,[{{Name,Arity},_}]}|Rest]) ->
@@ -130,6 +152,14 @@ make_list([{_,_,_,[{{Name,Arity},_}]}|Rest]) ->
{integer,0,Arity}]},
make_list(Rest)}.
+make_optional_list([]) -> {nil,0};
+make_optional_list([{Name,Arity}|Rest]) ->
+ {cons,0,
+ {tuple,0,
+ [{atom,0,Name},
+ {integer,0,Arity}]},
+ make_optional_list(Rest)}.
+
module_predef_funcs_mod_info(St) ->
PreDef = [{module_info,0},{module_info,1}],
PreExp = PreDef,