5 files changed, 33 insertions, 10 deletions
diff --git a/lib/diameter/bin/diameterc b/lib/diameter/bin/diameterc
index d31f341c36..2c9a8f555c 100755
--- a/lib/diameter/bin/diameterc
+++ b/lib/diameter/bin/diameterc
@@ -4,7 +4,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 2010-2013. All Rights Reserved.
+%% Copyright Ericsson AB 2010-2014. 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
@@ -74,7 +74,7 @@ compile(#argv{file = File, options = Opts, output = Out}) ->
         ok ->
             0;
         {error, Reason} ->
-            error_msg(Reason, []),
+            error_msg(diameter_make:format_error(Reason), []),
             1
     catch
         error: Reason ->
diff --git a/lib/diameter/doc/src/diameter_make.xml b/lib/diameter/doc/src/diameter_make.xml
index 1c1eff6c6a..16ef49d4b2 100644
--- a/lib/diameter/doc/src/diameter_make.xml
+++ b/lib/diameter/doc/src/diameter_make.xml
@@ -16,7 +16,7 @@
 <header>
 <copyright>
 <year>2012</year>
-<year>2013</year>
+<year>2014</year>
 <holder>Ericsson AB. All Rights Reserved.</holder>
 </copyright>
 <legalnotice>
@@ -175,6 +175,10 @@ Note that a dictionary's <c>&dict_name;</c>, together with the
 The <c>&dict_name;</c> of a literal input dictionary defaults to
 <c>dictionary</c>.</p>
 
+<p>
+A returned error reason can be converted into a readable string using
+&format_error;.</p>
+
 </desc>
 </func>
 
@@ -206,6 +210,18 @@ The return value is also a parsed dictionary.</p>
 </desc>
 </func>
 
+<!-- ===================================================================== -->
+
+<func>
+<name>format_error(Reason) -> string()</name>
+<fsummary>Turn an error reason into a readable string.</fsummary>
+<desc>
+
+<p>
+Turn an error reason returned by &codec; into a readable string.</p>
+</desc>
+</func>
+
 </funcs>
 
 <!-- ===================================================================== -->
diff --git a/lib/diameter/doc/src/seealso.ent b/lib/diameter/doc/src/seealso.ent
index 7bf7460351..44541afb9b 100644
--- a/lib/diameter/doc/src/seealso.ent
+++ b/lib/diameter/doc/src/seealso.ent
@@ -4,7 +4,7 @@
 
 %CopyrightBegin%
 
-Copyright Ericsson AB 2012-2013. All Rights Reserved.
+Copyright Ericsson AB 2012-2014. 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
@@ -117,6 +117,7 @@ significant.
 <!ENTITY make_codec '<seealso marker="diameter_make#codec-2">diameter_make:codec/2</seealso>'>
 <!ENTITY make_format '<seealso marker="diameter_make#format-1">diameter_make:format/1</seealso>'>
 <!ENTITY make_flatten '<seealso marker="diameter_make#flatten-1">diameter_make:flatten/1</seealso>'>
+<!ENTITY make_format_error '<seealso marker="diameter_make#format_error-1">diameter_make:format_error/1</seealso>'>
 
 <!-- diameter_transport -->
 
diff --git a/lib/diameter/src/compiler/diameter_make.erl b/lib/diameter/src/compiler/diameter_make.erl
index 2f314b7e57..adc7808e49 100644
--- a/lib/diameter/src/compiler/diameter_make.erl
+++ b/lib/diameter/src/compiler/diameter_make.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 2010-2013. All Rights Reserved.
+%% Copyright Ericsson AB 2010-2014. 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
@@ -33,7 +33,8 @@
 -export([codec/2,
          codec/1,
          format/1,
-         flatten/1]).
+         flatten/1,
+         format_error/1]).
 
 -export_type([opt/0]).
 
@@ -81,8 +82,8 @@ codec(File, Opts) ->
     case parse(Dict, Opts) of
         {ok, ParseD} ->
             make(Path, default(Opts), ParseD);
-        {error = E, Reason} ->
-            {E, diameter_dict_util:format_error(Reason)}
+        {error, _} = E ->
+            E
     end.
 
 codec(File) ->
@@ -115,6 +116,11 @@ flatten([?VERSION = V | Dict]) ->
                       [grouped, import_groups],
                       [enum, import_enums]])].
 
+%% format_error/1
+
+format_error(T) ->
+    diameter_dict_util:format_error(T).
+
 %% ===========================================================================
 
 %% flatten/2
diff --git a/lib/diameter/test/diameter_compiler_SUITE.erl b/lib/diameter/test/diameter_compiler_SUITE.erl
index cc423d5bc6..0b053219cd 100644
--- a/lib/diameter/test/diameter_compiler_SUITE.erl
+++ b/lib/diameter/test/diameter_compiler_SUITE.erl
@@ -397,8 +397,8 @@ replace({E, Mods}, Bin) ->
     case {E, parse(B, [{include, here()}]), Mods} of
         {ok, {ok, Dict}, _} ->
             Dict;
-        {_, {error, S}, _} when E /= ok ->
-            S
+        {_, {error, {E,_} = T}, _} when E /= ok ->
+            diameter_make:format_error(T)
     end.
 
 re({RE, Repl}, Bin) ->