have a server that like does stuff now

src/wfc_eval_context.erl

@@ -7,15 +7,17 @@
 -export([
     new/0,
     default/0,
+    default_snowflakes/0,
     define/3,
-    resolve_pattern/2
+    resolve_pattern/2,
+    resolve_snowflake/2
 ]).
 
 -type sentence() :: wfc_sentence:sentence().
 
 -record(ctx,
-        {snowflakes :: #{binary() := fun()},
-         patterns   :: #{binary() := sentence()}}).
+        {snowflakes = #{} :: #{binary() := fun(([sentence()]) -> {ok, sentence()} | {error, string()})},
+         patterns   = #{} :: #{binary() := sentence()}}).
 
 -opaque context() :: #ctx{}.
 
@@ -25,10 +27,12 @@ new() ->
          patterns   = #{}}.
 
 
-%% FIXME
 default() ->
-    new().
+    #ctx{snowflakes = default_snowflakes()}.
 
+default_snowflakes() ->
+    #{<<"and">> => fun wfc:mul/1,
+      <<"xor">> => fun wfc:add/1}.
 
 define(Pat, Sentence, Ctx = #ctx{patterns = OldPatterns}) ->
     NewPatterns = maps:put(Pat, Sentence, OldPatterns),
@@ -39,3 +43,9 @@ resolve_pattern(Pat, Ctx = #ctx{patterns = Patterns}) ->
         error -> {error, wfc_utils:str("wfc_eval_context:resolve_pattern: not found: ~w; context: ~w", [Pat, Ctx])};
         Result -> Result
     end.
+
+resolve_snowflake(SF, Ctx = #ctx{snowflakes = Snowflakes}) ->
+    case maps:find(SF, Snowflakes) of
+        error -> {error, wfc_utils:str("wfc_eval_context:resolve_snowflake: not found: ~w; context: ~w", [SF, Ctx])};
+        Result -> Result
+    end.