feat(variform): allow hyphens in identifiers

Fixes https://emqx.atlassian.net/browse/EMQX-12683

apps/emqx_utils/src/emqx_variform_scan.xrl

@@ -1,6 +1,6 @@
 Definitions.
 %% Define regular expressions for tokens
-IDENTIFIER  = [a-zA-Z][a-zA-Z0-9_.]*
+IDENTIFIER  = [a-zA-Z][-a-zA-Z0-9_.]*
 SQ_STRING   = \'[^\']*\'
 DQ_STRING   = \"[^\"]*\"
 INTEGER     = [+-]?[0-9]+

apps/emqx_utils/test/emqx_variform_tests.erl

@@ -23,7 +23,7 @@
 
 -define(SYNTAX_ERROR, {error, "syntax error before:" ++ _}).
 
-redner_test_() ->
+render_test_() ->
     [
         {"direct var reference", fun() -> ?assertEqual({ok, <<"1">>}, render("a", #{a => 1})) end},
         {"concat strings", fun() ->
@@ -32,6 +32,15 @@ redner_test_() ->
         {"concat empty string", fun() ->
             ?assertEqual({ok, <<"">>}, render("concat([''])", #{}))
         end},
+        {"identifier with hyphen", fun() ->
+            ?assertEqual(
+                {ok, <<"10">>},
+                render(
+                    "pub_props.Message-Expiry-Interval",
+                    #{pub_props => #{'Message-Expiry-Interval' => 10}}
+                )
+            )
+        end},
         {"tokens 1st", fun() ->
             ?assertEqual({ok, <<"a">>}, render("nth(1,tokens(var, ','))", #{var => <<"a,b">>}))
         end},