1 files changed, 57 insertions, 6 deletions
diff --git a/src/rebar_prv_new.erl b/src/rebar_prv_new.erl
index 698b14e..e22625c 100644
--- a/src/rebar_prv_new.erl
+++ b/src/rebar_prv_new.erl
@@ -30,15 +30,17 @@ init(State) ->
 -spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
 do(State) ->
     case rebar_state:command_args(State) of
-        [TemplateName] ->
-            Template = list_to_atom(TemplateName),
-            rebar_templater:new(Template, "", State),
+        ["help", TemplateName] ->
+            case lists:keyfind(TemplateName, 1, rebar_templater:list_templates(State)) of
+                false -> io:format("template not found.~n");
+                Term -> show_template(Term)
+            end,
             {ok, State};
-        [TemplateName, DirName] ->
-            Template = list_to_atom(TemplateName),
-            rebar_templater:new(Template, DirName, State),
+        [TemplateName | Opts] ->
+            ok = rebar_templater:new(TemplateName, parse_opts(Opts), State),
             {ok, State};
         [] ->
+            show_short_templates(rebar_templater:list_templates(State)),
             {ok, State}
     end.
 
@@ -56,3 +58,52 @@ info() ->
       "~n"
       "Valid command line options:~n"
       "  template= [var=foo,...]~n", []).
+
+parse_opts([]) -> [];
+parse_opts([Opt|Opts]) -> [parse_opt(Opt, "") | parse_opts(Opts)].
+
+%% We convert to atoms dynamically. Horrible in general, but fine in a
+%% build system's templating tool.
+parse_opt("", Acc) -> {list_to_atom(lists:reverse(Acc)), "true"};
+parse_opt("="++Rest, Acc) -> {list_to_atom(lists:reverse(Acc)), Rest};
+parse_opt([H|Str], Acc) -> parse_opt(Str, [H|Acc]).
+
+show_short_templates(List) ->
+    lists:map(fun show_short_template/1, lists:sort(List)).
+
+show_short_template({Name, Type, _Location, Description, _Vars}) ->
+    io:format("~s (~s): ~s~n",
+              [Name,
+               format_type(Type),
+               format_description(Description)]).
+
+show_template({Name, Type, Location, Description, Vars}) ->
+    io:format("~s:~n"
+              "\t~s~n"
+              "\tDescription: ~s~n"
+              "\tVariables:~n~s~n",
+              [Name,
+               format_type(Type, Location),
+               format_description(Description),
+               format_vars(Vars)]).
+
+format_type(escript) -> "built-in";
+format_type(file) -> "custom".
+
+format_type(escript, _) ->
+    "built-in template";
+format_type(file, Loc) ->
+    io_lib:format("custom template (~s)", [Loc]).
+
+format_description(Description) ->
+    case Description of
+        undefined -> "<missing description>";
+        _ -> Description
+    end.
+
+format_vars(Vars) -> [format_var(Var) || Var <- Vars].
+
+format_var({Var, Default}) ->
+    io_lib:format("\t\t~p=~p~n",[Var, Default]);
+format_var({Var, Default, Doc}) ->
+    io_lib:format("\t\t~p=~p (~s)~n", [Var, Default, Doc]).