Initial Commit

examples/simple/rebar.config

@@ -0,0 +1,13 @@
+
+{deps, [
+    {parse_trans, ".*",
+        {git, "https://github.com/esl/parse_trans.git"}},
+    {annotations, ".*", 
+        {git, "https://github.com/hyperthunk/annotations.git"}},
+    {delegate, ".*", {git, "../../.."}}
+]}.
+{plugins, [rebar_annotations_plugin]}.
+
+{annotations, [
+    {registered, [delegate]}
+]}.

examples/simple/src/simple.app.src

@@ -0,0 +1,9 @@
+{application, simple,
+ [
+  {description, "Simple Example of delegate in use"},
+  {vsn, "1"},
+  {applications, [
+                  kernel,
+                  stdlib
+                 ]}
+ ]}.

examples/simple/src/simple_log.erl

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+%% -----------------------------------------------------------------------------
+%% Copyright (c) 2002-2012 Tim Watson (watson.timothy@gmail.com)
+%%
+%% Permission is hereby granted, free of charge, to any person obtaining a copy
+%% of this software and associated documentation files (the "Software"), to deal
+%% in the Software without restriction, including without limitation the rights
+%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+%% copies of the Software, and to permit persons to whom the Software is
+%% furnished to do so, subject to the following conditions:
+%%
+%% The above copyright notice and this permission notice shall be included in
+%% all copies or substantial portions of the Software.
+%%
+%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+%% THE SOFTWARE.
+%% -----------------------------------------------------------------------------
+-module(simple_log).
+-export([log/3]).
+-include_lib("annotations/include/annotations.hrl").
+
+-delegate([{prefix, function},
+           {delegate, [error, warn, info, debug]}]).
+log(Level, Message, Args) ->
+    case get({?MODULE, loglevel}) of
+        Level ->
+            io:format(Message, Args);
+        _ ->
+            ok
+    end.

rebar.config

@@ -0,0 +1,14 @@
+
+{lib_dirs, ["deps/annotations"]}.
+{deps, [
+    {parse_trans, ".*",
+        {git, "https://github.com/esl/parse_trans.git"}},
+    {annotations, ".*", 
+        {git, "https://github.com/hyperthunk/annotations.git"}}
+]}.
+
+{plugins, [rebar_annotations_plugin]}.
+
+{annotations, [
+    {registered, [delegate]}
+]}.

src/delegate.app.src

@@ -0,0 +1,9 @@
+{application, delegate,
+ [
+  {description, ""},
+  {vsn, "0.0.1"},
+  {applications, [
+                  kernel,
+                  stdlib
+                 ]}
+ ]}.

src/delegate.erl

@@ -0,0 +1,52 @@
+%% -----------------------------------------------------------------------------
+%% Copyright (c) 2002-2012 Tim Watson (watson.timothy@gmail.com)
+%%
+%% Permission is hereby granted, free of charge, to any person obtaining a copy
+%% of this software and associated documentation files (the "Software"), to deal
+%% in the Software without restriction, including without limitation the rights
+%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+%% copies of the Software, and to permit persons to whom the Software is
+%% furnished to do so, subject to the following conditions:
+%%
+%% The above copyright notice and this permission notice shall be included in
+%% all copies or substantial portions of the Software.
+%%
+%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+%% THE SOFTWARE.
+%% -----------------------------------------------------------------------------
+-module(delegate).
+-include_lib("annotations/include/types.hrl").
+-export([codegen/3, codegen_advised/4]).
+
+codegen(A=#annotation{name=N, data=Data}, _Mod, AST) ->
+    case lists:keyfind(N, 1, Data) of
+        Delegates when is_list(Delegates) ->
+            %% NB: this *can* return either {gen_function, Name}, in which case
+            %% we generate a function that calls ?MODULE:codegen_advised/4 - or -
+            %% you return {add_function, Name, codegen:gen_function/2/3} in which case
+            %% you need -include_lib("parse_trans/include/codegen.hrl"), and this
+            %% will be added and exported as-is
+
+            %% NB: you need a *little* understanding of erl_syntax to use these
+            %% kinds of callbacks
+            {FN, _} = erl_syntax:analyze_function(AST),
+            [ {D, A#annotation{data=[{function, FN}|Data]}} || D <- Delegates ];
+        _ ->
+            %% TODO: clearer error handling API
+            {error, "no delegates defined"}
+    end.
+
+codegen_advised(#annotation{data=AnnotationData}, M, F, Inputs) ->
+    Argv = case lists:keyfind(prefix, 1, AnnotationData) of
+        true ->
+            [F|Inputs];
+        false ->
+            Inputs
+    end,
+    Target = lists:keyfind(target, 1, AnnotationData),
+    erlang:apply(M, Target, [Argv]).