ocaml: pattern parsing

ocaml/libsyntax/syntax.ml

@@ -63,6 +63,15 @@ let next_in_noeof ps (ctx : error_ctx) =
         let sp = { start = ps.offset; length = zero_len } in
         Yanais_syntax_err (EUnexpectedEof ctx, ps.file, sp) |> raise
 
+(* make an optional parser required *)
+let require ctx parse_inner ps = match parse_inner ps with
+  | Some x -> x
+  | None ->
+      let sp = match ps.lt with
+        | (_, sp)::_ -> sp
+        | [] -> { start = ps.offset; length = zero_len }
+      in Yanais_syntax_err (EExpected ctx, ps.file, sp) |> raise
+
 module FieldsReg = Set.Make(String)
 
 let parse_record (type a) parse_inner ps = when_got ps (Brace Open) (fun (_, ps) -> (
@@ -107,6 +116,16 @@ let parse_record (type a) parse_inner ps = when_got ps (Brace Open) (fun (_, ps)
       inner [] FieldsReg.empty ps
   ))
 
+let rec parse_pattern ps = match ps.lt with
+  | (PatOut "", s)::lt ->
+      Some (PatIgnore (ps.file, s),                             { ps with lt; offset = loc_span_end s; })
+  | (PatOut name, s)::lt ->
+      Some (PatName {ident = name; file = ps.file; span = s; }, { ps with lt; offset = loc_span_end s; })
+  | (Brace Open, _)::_ ->
+      let rqp_pattern = require XPattern parse_pattern in
+      Some (require XRecord (parse_record rqp_pattern) ps |> (fun (x, ps) -> (PatRecord x, ps)))
+  | _ -> None
+
 (*
 let parse_expr ps =
   match parse_one ps with

ocaml/libsyntax/tys.ml

@@ -10,7 +10,11 @@ type loc_span_full = string * loc_span
 
 let loc_span_end ls = ls.start + Unsigned.UInt32.to_int ls.length
 
-type tagged_ident = TaggedIdent of loc_span_full * string
+type tagged_ident =
+  { ident: string
+  ; file : string
+  ; span : loc_span
+  }
 
 type grp_state = Open | Close