Introduce different verbosity levels.

Defined levels are INFO, DEBUG and TRACE.

For each `verbose` option present in the compiler options,
the verbosity level used is put up a notch
(i.e. `[... verbose, verbose, ...]` yields INFO and DEBUG output).

include/erlydtl_ext.hrl

@@ -24,7 +24,7 @@
           compiler_options = [],
           binary_strings = true,
           force_recompile = false,
-          verbose = false,
+          verbose = 0,
           is_compiling_dir = false,
           extension_module = undefined,
           scanner_module = erlydtl_scanner,
@@ -60,3 +60,11 @@
 
 -define(ERR(Err, Ctx), erlydtl_compiler_utils:add_error(?MODULE, Err, Ctx)).
 -define(WARN(Warn, Ctx), erlydtl_compiler_utils:add_warning(?MODULE, Warn, Ctx)).
+
+-define(V_INFO,1).
+-define(V_DEBUG,2).
+-define(V_TRACE,3).
+
+-define(LOG_INFO(Fmt, Args, Ctx), erlydtl_compiler_utils:print(?V_INFO, Fmt, Args, Ctx)).
+-define(LOG_DEBUG(Fmt, Args, Ctx), erlydtl_compiler_utils:print(?V_DEBUG, Fmt, Args, Ctx)).
+-define(LOG_TRACE(Fmt, Args, Ctx), erlydtl_compiler_utils:print(?V_TRACE, Fmt, Args, Ctx)).

src/erlydtl_beam_compiler.erl

@@ -60,7 +60,7 @@
 -import(erlydtl_compiler_utils,
         [unescape_string_literal/1, full_path/2, push_scope/2,
          restore_scope/2, begin_scope/1, begin_scope/2, end_scope/4,
-         empty_scope/0, print/3, get_current_file/1, add_errors/2,
+         empty_scope/0, get_current_file/1, add_errors/2,
          add_warnings/2, merge_info/2, call_extension/3,
          init_treewalker/1, resolve_variable/2, resolve_variable/3,
          reset_parse_trail/2, load_library/3, load_library/4]).
@@ -241,7 +241,7 @@ maybe_write(Module, Bin, Context) ->
             ?WARN(no_out_dir, Context);
         OutDir ->
             BeamFile = filename:join([OutDir, [Module, ".beam"]]),
-            print("Template module: ~w -> ~s\n", [Module, BeamFile], Context),
+            ?LOG_INFO("Template module: ~w -> ~s\n", [Module, BeamFile], Context),
             case file:write_file(BeamFile, Bin) of
                 ok -> Context;
                 {error, Reason} ->
@@ -268,7 +268,7 @@ maybe_debug_template(Forms, Context) ->
         false -> nop;
         true ->
             Options = Context#dtl_context.compiler_options,
-            print("Compiler options: ~p~n", [Options], Context),
+            ?LOG_DEBUG("Compiler options: ~p~n", [Options], Context),
             try
                 Source = erl_prettypr:format(erl_syntax:form_list(Forms)),
                 File = lists:concat([proplists:get_value(source, Options), ".erl"]),

src/erlydtl_compiler.erl

@@ -51,7 +51,7 @@
 -export([parse_file/2, parse_template/2, do_parse_template/2]).
 
 -import(erlydtl_compiler_utils,
-         [add_filters/2, add_tags/2, print/3, call_extension/3,
+         [add_filters/2, add_tags/2, call_extension/3,
          load_library/2]).
 
 -include("erlydtl_ext.hrl").
@@ -69,12 +69,12 @@ compile_template(Template, Module, Options) ->
 
 compile_file(File, Module, Options) ->
     Context = process_opts(File, Module, Options),
-    print("Compile template: ~s~n", [File], Context),
+    ?LOG_INFO("Compile template: ~s~n", [File], Context),
     compile(Context).
 
 compile_dir(Dir, Module, Options) ->
     Context = process_opts({dir, Dir}, Module, Options),
-    print("Compile directory: ~s~n", [Dir], Context),
+    ?LOG_INFO("Compile directory: ~s~n", [Dir], Context),
     compile(Context).
 
 
@@ -253,7 +253,7 @@ init_context(ParseTrail, DefDir, Module, Options) ->
            compiler_options = proplists:append_values(compiler_options, Options),
            binary_strings = proplists:get_value(binary_strings, Options, Ctx#dtl_context.binary_strings),
            force_recompile = proplists:get_bool(force_recompile, Options),
-           verbose = proplists:get_value(verbose, Options, Ctx#dtl_context.verbose),
+           verbose = length(proplists:get_all_values(verbose, Options)),
            is_compiling_dir = ParseTrail == [],
            extension_module = proplists:get_value(extension_module, Options, Ctx#dtl_context.extension_module),
            scanner_module = proplists:get_value(scanner_module, Options, Ctx#dtl_context.scanner_module),

src/erlydtl_compiler_utils.erl

@@ -58,6 +58,7 @@
          load_library/4,
          merge_info/2,
          print/3,
+         print/4,
          to_string/2,
          unescape_string_literal/1,
          reset_parse_trail/2,
@@ -99,8 +100,16 @@ full_path(File, DocRoot) ->
         _ -> filename:join([DocRoot, File])
     end.
 
-print(Fmt, Args, #dtl_context{ verbose = true }) -> io:format(Fmt, Args);
-print(_Fmt, _Args, _Context) -> ok.
+print(Fmt, Args, Context) ->
+    print(?V_INFO, Fmt, Args, Context).
+
+print(Verbosity, Fmt, Args, #treewalker{ context=Context }) ->
+    print(Verbosity, Fmt, Args, Context);
+print(Verbosity, Fmt, Args, #dtl_context{ verbose = Verbose })
+  when Verbosity =< Verbose ->
+    io:format(Fmt, Args);
+print(_Verbosity, _Fmt, _Args, _Context) ->
+    ok.
 
 get_current_file(#treewalker{ context=Context }) ->
     get_current_file(Context);