Add poc files

h_program-lang/prolog_code.mli

@@ -0,0 +1,26 @@
+
+type fact =
+  | At of entity * Common.filename (* readable path *) * int (* line *)
+  | Kind of entity * Entity_code.entity_kind
+  | Type of entity * string
+
+  | Extends of string * string 
+  | Implements of string * string
+  | Mixins of string * string
+
+  | Privacy of entity * Entity_code.privacy
+
+  | Call of entity * entity
+  | UseData of entity * entity * bool option (* read/write *)
+  | Special of entity * entity * entity * string (* field/function *)
+
+  | Misc of string
+
+  and entity = 
+   string list (* package/module/namespace/class qualifier*) * string (* name *)
+
+val string_of_fact: fact -> string
+val entity_of_str: string -> entity
+
+(* reused in other modules which generate prolog facts *)
+val string_of_entity_kind: Entity_code.entity_kind -> string