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Remove Reject from Hocc parser API #336

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Merged
jasone merged 1 commit into from
May 27, 2026
Merged

Remove Reject from Hocc parser API #336

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33 changes: 19 additions & 14 deletions bootstrap/bin/hocc/Parse.hmh
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Original file line number Diff line number Diff line change
Expand Up @@ -756,12 +756,8 @@ let hmhi scanner =
| [] -> errs
| _ -> List.fold ~init:errs ~f:(fun errs mal -> Error.init_mal mal :: errs) mals
in
let {status; _} as parser = next token parser in
match status, errs with
| Prefix, _ -> inner scanner errs parser
| Accept (Hmhi hmhi), [] -> scanner, Ok hmhi
| Accept (Hmhi _), _ -> scanner, Error errs
| Reject _, _ ->
match next token parser with
| Error _ -> begin
let msg =
String.Fmt.empty
|> Fmt.fmt "Unexpected token not in "
Expand All @@ -770,7 +766,14 @@ let hmhi scanner =
in
let errs = Error.init_token scan_token msg :: errs in
scanner, Error errs
| _ -> not_reached ()
end
| Ok ({status; _} as parser) -> begin
match status, errs with
| Prefix, _ -> inner scanner errs parser
| Accept (Hmhi hmhi), [] -> scanner, Ok hmhi
| Accept (Hmhi _), _ -> scanner, Error errs
| _ -> not_reached ()
end
end in
let parser = Start.Hmhi.boi in
inner scanner [] parser
Expand All @@ -782,12 +785,8 @@ let hmh scanner =
| [] -> errs
| _ -> List.fold ~init:errs ~f:(fun errs mal -> Error.init_mal mal :: errs) mals
in
let {status; _} as parser = next token parser in
match status, errs with
| Prefix, _ -> inner scanner errs parser
| Accept (Hmh hmh), [] -> scanner, Ok hmh
| Accept (Hmh _), _ -> scanner, Error errs
| Reject _, _ -> begin
match next token parser with
| Error _ -> begin
let msg =
String.Fmt.empty
|> Fmt.fmt "Unexpected token not in "
Expand All @@ -797,7 +796,13 @@ let hmh scanner =
let errs = Error.init_token scan_token msg :: errs in
scanner, Error errs
end
| _ -> not_reached ()
| Ok ({status; _} as parser) -> begin
match status, errs with
| Prefix, _ -> inner scanner errs parser
| Accept (Hmh hmh), [] -> scanner, Ok hmh
| Accept (Hmh _), _ -> scanner, Error errs
| _ -> not_reached ()
end
end in
let parser = Start.Hmh.boi in
inner scanner [] parser
Expand Down
95 changes: 48 additions & 47 deletions bootstrap/bin/hocc/Parse.ml
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Original file line number Diff line number Diff line change
Expand Up @@ -15116,15 +15116,13 @@ Hmhi {prelude; hocc_; postlude; eoi}
| Reduce of Token.t * Stack.Reduction.t
| Prefix
| Accept of Nonterm.t
| Reject of Token.t

let constructor_index = function
| ShiftPrefix _ -> 0L
| ShiftAccept _ -> 1L
| Reduce _ -> 2L
| Prefix -> 3L
| Accept _ -> 4L
| Reject _ -> 5L

let hash_fold t state =
state
Expand All @@ -15138,7 +15136,6 @@ Hmhi {prelude; hocc_; postlude; eoi}
hash_state |> Stack.Reduction.hash_fold reduction |> Token.hash_fold token
| Prefix -> hash_state
| Accept nonterm -> hash_state |> Nonterm.hash_fold nonterm
| Reject token -> hash_state |> Token.hash_fold token
)

let cmp t0 t1 =
Expand All @@ -15163,7 +15160,6 @@ Hmhi {prelude; hocc_; postlude; eoi}
end
| Prefix, Prefix -> Eq
| Accept nonterm0, Accept nonterm1 -> Nonterm.cmp nonterm0 nonterm1
| Reject token0, Reject token1 -> Token.cmp token0 token1
| _, _ -> not_reached ()
end
| Gt -> Gt
Expand Down Expand Up @@ -15192,7 +15188,6 @@ Hmhi {prelude; hocc_; postlude; eoi}
end
| Prefix -> formatter |> Fmt.fmt "Prefix"
| Accept nonterm -> formatter |> Fmt.fmt "Accept " |> Nonterm.pp nonterm
| Reject token -> formatter |> Fmt.fmt "Reject " |> Token.pp token
)
end
include T
Expand Down Expand Up @@ -15225,29 +15220,29 @@ Hmhi {prelude; hocc_; postlude; eoi}
end
end

let feed token = function
let feed token t = match t with
| {stack={state; _} :: _; status=Prefix} as t -> begin
let token_index = Token.index token in
let Spec.State.{actions; _} = Array.get state Spec.states in
let status = match Map.get token_index actions with
| Some (Spec.Action.ShiftPrefix state') -> Status.ShiftPrefix (token, state')
| Some (Spec.Action.ShiftAccept state') -> Status.ShiftAccept (token, state')
match Map.get token_index actions with
| Some (Spec.Action.ShiftPrefix state') ->
Ok {t with status=Status.ShiftPrefix (token, state')}
| Some (Spec.Action.ShiftAccept state') ->
Ok {t with status=Status.ShiftAccept (token, state')}
| Some (Spec.Action.Reduce prod_index) -> begin
let Spec.Prod.{callback=callback_index; _} = Array.get prod_index Spec.prods in
let reduction = Stack.Reduction.init callback_index in
Status.Reduce (token, reduction)
Ok {t with status=Status.Reduce (token, reduction)}
end
| None -> Status.Reject token
in
{t with status}
| None -> Error (token, t)
end
| _ -> not_reached ()

let step {stack; status} =
let open Status in
match status with
| ShiftPrefix (token, state) ->
{stack=Stack.shift ~symbol:(Token token) ~state stack; status=Prefix}
Ok {stack=Stack.shift ~symbol:(Token token) ~state stack; status=Prefix}
| ShiftAccept (token, state) -> begin
(* Shift, perform the ⊥ reduction, and extract the accepted symbol from the stack. *)
let stack = Stack.shift ~symbol:(Token token) ~state stack in
Expand All @@ -15261,47 +15256,48 @@ Hmhi {prelude; hocc_; postlude; eoi}
match stack with
| [] -> not_reached ()
| {symbol=Token _; _} :: _ -> not_reached ()
| {symbol=Nonterm nonterm; _} :: _ -> {stack=[]; status=Accept nonterm}
| {symbol=Nonterm nonterm; _} :: _ -> Ok {stack=[]; status=Accept nonterm}
end
| _ -> not_reached ()
end
| Reduce (token, reduction) -> begin
feed token {stack=Stack.reduce ~reduction stack; status=Prefix}
end
| _ -> not_reached ()
| _ -> halt "`step` only supports {`ShiftPrefix`, `ShiftAccept`, `Reduce`} status"

(* val walk: t -> t *)
(* val walk: t -> (t, Token.t * t) result *)
let rec walk ({status; _} as t) =
let open Status in
match status with
| ShiftPrefix _
| ShiftAccept _
| Reduce _ -> t |> step |> walk
| Reduce _ -> begin
match step t with
| (Error _) as error -> error
| Ok t' -> walk t'
end
| Prefix
| Accept _
| Reject _ -> t
| Accept _ -> Ok t

let next token ({status; _} as t) =
let open Status in
match status with
| Prefix -> begin
match t |> feed token |> walk with
| {status=Reject _ as status; _} -> {t with status}
| t' -> t'
match feed token t with
| (Error _) as error -> error
| Ok t' -> begin
match walk t' with
| Error _ -> Error (token, t)
| (Ok _) as ok -> ok
end
end
| _ -> halt "`token` only supports `Prefix` status"
| _ -> halt "`next` only supports `Prefix` status"

let expect ({status; _} as t) =
let open Status in
let t = match status with
| Prefix -> t
| Reject _ -> {t with status=Prefix}
| _ -> halt "`expect` only supports `Prefix`/`Reject` status"
in
let expect t =
Array.fold ~init:(Ordset.empty (module Token)) ~f:(fun expect token ->
match next token t with
| {status=Reject _; _} -> expect
| _ -> Ordset.insert token expect
| Error _ -> expect
| Ok _ -> Ordset.insert token expect
) Token.protos
end
#678 "./Parse.hmh"
Expand Down Expand Up @@ -15386,12 +15382,8 @@ let hmhi scanner =
| [] -> errs
| _ -> List.fold ~init:errs ~f:(fun errs mal -> Error.init_mal mal :: errs) mals
in
let {status; _} as parser = next token parser in
match status, errs with
| Prefix, _ -> inner scanner errs parser
| Accept (Hmhi hmhi), [] -> scanner, Ok hmhi
| Accept (Hmhi _), _ -> scanner, Error errs
| Reject _, _ ->
match next token parser with
| Error _ -> begin
let msg =
String.Fmt.empty
|> Fmt.fmt "Unexpected token not in "
Expand All @@ -15400,7 +15392,14 @@ let hmhi scanner =
in
let errs = Error.init_token scan_token msg :: errs in
scanner, Error errs
| _ -> not_reached ()
end
| Ok ({status; _} as parser) -> begin
match status, errs with
| Prefix, _ -> inner scanner errs parser
| Accept (Hmhi hmhi), [] -> scanner, Ok hmhi
| Accept (Hmhi _), _ -> scanner, Error errs
| _ -> not_reached ()
end
end in
let parser = Start.Hmhi.boi in
inner scanner [] parser
Expand All @@ -15412,12 +15411,8 @@ let hmh scanner =
| [] -> errs
| _ -> List.fold ~init:errs ~f:(fun errs mal -> Error.init_mal mal :: errs) mals
in
let {status; _} as parser = next token parser in
match status, errs with
| Prefix, _ -> inner scanner errs parser
| Accept (Hmh hmh), [] -> scanner, Ok hmh
| Accept (Hmh _), _ -> scanner, Error errs
| Reject _, _ -> begin
match next token parser with
| Error _ -> begin
let msg =
String.Fmt.empty
|> Fmt.fmt "Unexpected token not in "
Expand All @@ -15427,7 +15422,13 @@ let hmh scanner =
let errs = Error.init_token scan_token msg :: errs in
scanner, Error errs
end
| _ -> not_reached ()
| Ok ({status; _} as parser) -> begin
match status, errs with
| Prefix, _ -> inner scanner errs parser
| Accept (Hmh hmh), [] -> scanner, Ok hmh
| Accept (Hmh _), _ -> scanner, Error errs
| _ -> not_reached ()
end
end in
let parser = Start.Hmh.boi in
inner scanner [] parser
Expand Down
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