-and substitute loc env substs =
- let b = Buffer.create 13 in
- List.iter (
- function
- | Ast.SString s -> Buffer.add_string b s
- | Ast.SVar name ->
- let expr =
- try Ast.StringMap.find name env
- with Not_found ->
- failwithf "%a: variable ‘%s’ not found" Ast.string_loc loc name in
- match simplify env expr with
- | Ast.CString s -> Buffer.add_string b s
- ) substs;
- Buffer.contents b
+and matching_param env loc params res targ carg =
+ match carg with
+ | Ast.CString carg ->
+ (* Substitute any non parameters in targ from the environment. *)
+ let targ =
+ List.map (
+ function
+ | Ast.SString _ as s -> s
+ | Ast.SVar name ->
+ if not (List.mem name params) then (
+ try
+ let expr = Ast.getvar env loc name in
+ match Ast.to_constant env expr with
+ | Ast.CString s -> Ast.SString s
+ with Failure _ -> raise Not_found
+ )
+ else
+ Ast.SVar name
+ ) targ in
+
+ (* Do the actual pattern matching. Any remaining SVar elements
+ * must refer to goal parameters.
+ *)
+ let carg = ref carg in
+ let rec loop = function
+ | [] ->
+ (* End of targ, we must have matched all of carg. *)
+ if !carg <> "" then raise Not_found
+ | Ast.SString s :: rest ->
+ (* Does this match the first part of !carg? *)
+ let clen = String.length !carg in
+ let slen = String.length s in
+ if slen > clen || s <> String.sub !carg 0 slen then
+ raise Not_found;
+ (* Yes, so continue after the matching prefix. *)
+ carg := String.sub !carg slen (clen-slen);
+ loop rest
+ | Ast.SVar name :: Ast.SString s :: rest ->
+ (* This is a goal parameter. Find s later in !carg. *)
+ let i = string_find !carg s in
+ if i = -1 then raise Not_found;
+ (* Set the binding in !res. *)
+ let r = Ast.EConstant (Ast.noloc,
+ Ast.CString (String.sub !carg 0 i)) in
+ res := Ast.Env.add name r !res;
+ (* Continue after the match. *)
+ let skip = i + String.length s in
+ carg := String.sub !carg skip (String.length !carg - skip);
+ loop rest
+ | Ast.SVar name :: [] ->
+ (* Matches the whole remainder of the string. *)
+ let r = Ast.EConstant (Ast.noloc, Ast.CString !carg) in
+ res := Ast.Env.add name r !res
+ | Ast.SVar x :: Ast.SVar y :: _ ->
+ (* TODO! We cannot match a target like "%x%y". *)
+ assert false
+ in
+ loop targ