Add support for not equal

README.org

@@ -51,6 +51,11 @@ Select all events where 'a' exists and is equal to 0.
     glc:eq(a, 0).
 #+END_EXAMPLE
 
+Select all events where 'a' exists and is not equal to 0.
+#+BEGIN_EXAMPLE
+    glc:neq(a, 0).
+#+END_EXAMPLE
+
 Select all events where 'a' exists and is less than 0.
 #+BEGIN_EXAMPLE
     glc:lt(a, 0).
@@ -220,6 +225,8 @@ or
 #+END_EXAMPLE
 
 * CHANGELOG 
+0.1.8
+- Add support for not equal
 
 0.1.7
 - Support multiple functions specified using `with/2` 

src/glc.erl

@@ -28,6 +28,8 @@
 %% glc:gt(a, 0).
 %% %% Select all events where 'a' exists and is equal to 0.
 %% glc:eq(a, 0).
+%% %% Select all events where 'a' exists and is not equal to 0.
+%% glc:neq(a, 0).
 %% %% Select all events where 'a' exists and is less than 0.
 %% glc:lt(a, 0).
 %% %% Select all events where 'a' exists and is anything.
@@ -74,7 +76,7 @@
 
 -export([
     lt/2, lte/2,
-    eq/2,
+    eq/2, neq/2,
     gt/2, gte/2,
     wc/1,
     nf/1
@@ -113,6 +115,10 @@ lte(Key, Term) ->
 eq(Key, Term) ->
     glc_ops:eq(Key, Term).
 
+-spec neq(atom(), term()) -> glc_ops:op().
+neq(Key, Term) ->
+    glc_ops:neq(Key, Term).
+
 -spec gt(atom(), term()) -> glc_ops:op().
 gt(Key, Term) ->
     glc_ops:gt(Key, Term).
@@ -434,13 +440,23 @@ events_test_() ->
                 fun() ->
                     %% If a selection condition but no body is specified the event
                     %% counts as input to the query, but not as filtered out.
-                    {compiled, Mod} = setup_query(testmod7, glc:eq('$n', 'noexists@nohost')),
+                    {compiled, Mod} = setup_query(testmod7a, glc:eq('$n', 'noexists@nohost')),
                     glc:handle(Mod, gre:make([{'$n', 'noexists@nohost'}], [list])),
                     ?assertEqual(1, Mod:info(input)),
                     ?assertEqual(0, Mod:info(filter)),
                     ?assertEqual(1, Mod:info(output))
                 end
             },
+            {"opfilter not equal test",
+                fun() ->
+                    {compiled, Mod} = setup_query(testmod7b, glc:neq('$n', 'noexists@nohost')),
+                    glc:handle(Mod, gre:make([{'$n', 'noexists@nohost'}], [list])),
+                    glc:handle(Mod, gre:make([{'$n', 'notexists@nohost'}], [list])),
+                    ?assertEqual(2, Mod:info(input)),
+                    ?assertEqual(1, Mod:info(filter)),
+                    ?assertEqual(1, Mod:info(output))
+                end
+            },
             {"opfilter wildcard test",
                 fun() ->
                     {compiled, Mod} = setup_query(testmod8, glc:wc(a)),

src/glc_code.erl

@@ -253,10 +253,11 @@ abstract_filter_({Key, '!'}, OnMatch, OnNomatch, State) ->
         _OnMatch=fun(#state{}=State2) -> OnMatch(State2) end,
                     State);
 abstract_filter_({Key, Op, Value}, OnMatch, OnNomatch, State)
-        when Op =:= '>'; Op =:= '='; Op =:= '<';
+        when Op =:= '>'; Op =:= '='; Op =:= '!='; Op =:= '<';
              Op =:= '>='; Op =:= '=<'; Op =:= '<=' ->
     Op2 = case Op of 
               '=' -> '=:=';  
+              '!=' -> '=/=';  
               '<=' -> '=<';
               Op -> Op 
           end,

src/glc_lib.erl

@@ -65,6 +65,11 @@ matches({Key, '=', Term}, Event) ->
         {true, Term2} -> Term2 =:= Term;
         false -> false
     end;
+matches({Key, '!=', Term}, Event) ->
+    case gre:find(Key, Event) of
+        {true, Term2} -> Term2 =/= Term;
+        false -> false
+    end;
 matches({Key, '>', Term}, Event) ->
     case gre:find(Key, Event) of
         {true, Term2} -> Term2 > Term;
@@ -253,6 +258,8 @@ is_valid({Field, '=<', _Term}) when is_atom(Field) ->
     true;
 is_valid({Field, '=', _Term}) when is_atom(Field) ->
     true;
+is_valid({Field, '!=', _Term}) when is_atom(Field) ->
+    true;
 is_valid({Field, '>=', _Term}) when is_atom(Field) ->
     true;
 is_valid({Field, '>', _Term}) when is_atom(Field) ->

src/glc_ops.erl

@@ -3,7 +3,7 @@
 
 -export([
     lt/2, lte/2,
-    eq/2,
+    eq/2, neq/2,
     gt/2, gte/2,
     wc/1,
     nf/1
@@ -23,6 +23,7 @@
 -type op() ::
     {atom(), '=<', term()} |
     {atom(), '=', term()} |
+    {atom(), '!=', term()} |
     {atom(), '>', term()} |
     {atom(), '>=', term()} |
     {atom(), '*'} |
@@ -55,6 +56,14 @@ eq(Key, Term) when is_atom(Key) ->
 eq(Key, Term) ->
     erlang:error(badarg, [Key, Term]).
 
+%% @doc Test that a field value is not equal to a term.
+-spec neq(atom(), term()) -> op().
+neq(Key, Term) when is_atom(Key) ->
+    {Key, '!=', Term};
+neq(Key, Term) ->
+    erlang:error(badarg, [Key, Term]).
+
+
 %% @doc Test that a field value is greater than a term.
 -spec gt(atom(), term()) -> op().
 gt(Key, Term) when is_atom(Key) ->