Parameter Make.State

include Support.State.STATE
type state

The type of states inside the monad.

type 'a t = state -> state * 'a
val get : state t

Return the state from the internals of the monad.

val put : state -> unit t

Replace the state inside the monad.

val modify : (state -> state) -> unit t

Modify the state inside the monad.

val run : 'a t -> state -> state * 'a

run a init runs a with initial state init, returning (final, v) where final is the final state and v is the output.

val eval : 'a t -> state -> 'a

eval a init is run a init = (final, v), but outputs only v.

val exec : 'a t -> state -> state

exec a init is run a init = (final, v), but outputs only final.

Traversals

val traverse_tuple2 : ('a1 -> 'b1 t) -> ('a2 -> 'b2 t) -> ('a1 * 'a2) -> ('b1 * 'b2) t
val traverse_tuple3 : ('a1 -> 'b1 t) -> ('a2 -> 'b2 t) -> ('a3 -> 'b3 t) -> ('a1 * 'a2 * 'a3) -> ('b1 * 'b2 * 'b3) t
val traverse_list : ('a -> 'b t) -> 'a Support.List.t -> 'b Support.List.t t
val traverse_list1 : ('a -> 'b t) -> 'a Support.List1.t -> 'b Support.List1.t t
val traverse_list2 : ('a -> 'b t) -> 'a Support.List2.t -> 'b Support.List2.t t
val traverse_list_void : ('a -> _ t) -> 'a Support.List.t -> Stdlib.Unit.t t
val traverse_list1_void : ('a -> _ t) -> 'a Support.List1.t -> Stdlib.Unit.t t
val traverse_list2_void : ('a -> _ t) -> 'a Support.List2.t -> Stdlib.Unit.t t
val traverse_reverse_list : ('a -> 'b t) -> 'a Support.List.t -> 'b Support.List.t t
val traverse_reverse_list1 : ('a -> 'b t) -> 'a Support.List1.t -> 'b Support.List1.t t
val traverse_reverse_list2 : ('a -> 'b t) -> 'a Support.List2.t -> 'b Support.List2.t t
val traverse_reverse_list_void : ('a -> _ t) -> 'a Support.List.t -> Stdlib.Unit.t t
val traverse_reverse_list1_void : ('a -> _ t) -> 'a Support.List1.t -> Stdlib.Unit.t t
val traverse_reverse_list2_void : ('a -> _ t) -> 'a Support.List2.t -> Stdlib.Unit.t t
val traverse_option : ('a -> 'b t) -> 'a Support.Option.t -> 'b Support.Option.t t
val traverse_option_void : ('a -> _ t) -> 'a Support.Option.t -> Stdlib.Unit.t t
val seq_list : 'a t Support.List.t -> 'a Support.List.t t
val seq_list1 : 'a t Support.List1.t -> 'a Support.List1.t t
val seq_list_void : unit t list -> unit t

seq_list_void [x1; x2; ...; xn] performs x1, x2, ..., xn in order.

Instances

include Support.Monad.MONAD with type 'a t := 'a t
val return : 'a -> 'a t

return a injects a into the monadic type.

val bind : ('a -> 'b t) -> 'a t -> 'b t

bind f a is the sequential composition of two actions, passing any value produced by a as argument to f.

val (>>=) : 'a t -> ('a -> 'b t) -> 'b t

Operator alias of bind.

val compose : ('b -> 'c t) -> ('a -> 'b t) -> 'a -> 'c t

compose g f is the Kleisli composition of f and g, passing the input to f, then binding the output to g.

val (>=>) : ('a -> 'b t) -> ('b -> 'c t) -> 'a -> 'c t

Operator alias of compose.

val (let*) : 'a t -> ('a -> 'b t) -> 'b t

( let* ) ma f is bind f ma. This is a binding operator, and it is used as let* a = ma in f a.

val (and*) : 'a t -> 'b t -> ('a * 'b) t

( and* ) ma mb is let* a = ma in let* b = mb in return (a, b). This is a binding operator, and it is used as let* a = ma and* b = mb in ....

include Support.Functor.FUNCTOR with type 'a t := 'a t

Combinators

val map : ('a -> 'b) -> 'a t -> 'b t

map f is the function that maps values of t by f. The order of arguments is for use in function pipelines as fb = fa |> map (fun a -> (* ... *)).

val ($>) : 'a t -> ('a -> 'b) -> 'b t

( $> ) is an infix synonym for map.

val (let+) : 'a t -> ('a -> 'b) -> 'b t

( let+ ) ma f is map f a. This is a binding operator, and is used as let+ a = ma in f a

val (and+) : 'a t -> 'b t -> ('a * 'b) t

( and+ ) ma mb is let+ a = ma in let+ b = mb in return (a, b). This is a binding operator, and it is used as let+ a = ma and+ b = mb in ....

include Support.Apply.APPLY with type 'a t := 'a t
val ap : 'a t -> ('a -> 'b) t -> 'b t

ap fa fab applies argument fa to fab under the abstract datatype t.

val (<&>) : ('a -> 'b) t -> 'a t -> 'b t

( <&> ) is an infix synonym of ap.

Combinators

val ap_first : 'b t -> 'a t -> 'a t

ap_first second first combines actions first and second but keeps only first. That is, ap_first second first = first. The order of arguments is for use in function pipelines as first = first |> ap_first second.

val (<&) : 'a t -> 'b t -> 'a t

( <& ) is an infix synonym for ap_first.

val ap_second : 'b t -> 'a t -> 'b t

ap_second second first combines actions first and second but keeps only second. That is, ap_second second first = second. The order of arguments is for use in function pipelines as second = first |> ap_second second.

val (&>) : 'a t -> 'b t -> 'b t

( &> ) is an infix synonym for ap_second.

val seq2 : 'a1 t -> 'a2 t -> ('a1 * 'a2) t

seq2 fa1 fa2 sequentially executes actions fa1 and fa2, and keeps their outputs under the abstract datatype t.

val seq3 : 'a1 t -> 'a2 t -> 'a3 t -> ('a1 * 'a2 * 'a3) t

seq3 fa1 fa2 fa3 sequentially executes actions fa1, fa2 and fa3, and keeps their outputs under the abstract datatype t.

val seq4 : 'a1 t -> 'a2 t -> 'a3 t -> 'a4 t -> ('a1 * 'a2 * 'a3 * 'a4) t

seq4 fa1 fa2 fa3 fa4 sequentially executes actions fa1, fa2, fa3 and fa4, and keeps their outputs under the abstract datatype t.

val seq5 : 'a1 t -> 'a2 t -> 'a3 t -> 'a4 t -> 'a5 t -> ('a1 * 'a2 * 'a3 * 'a4 * 'a5) t

seq5 fa1 fa2 fa3 fa4 fa5 sequentially executes actions fa1, fa2, fa3, fa4 and fa5, and keeps their outputs under the abstract datatype t.

val lift2 : ('a1 -> 'a2 -> 'r) -> 'a1 t -> 'a2 t -> 'r t

lift2 f ma1 ma2 sequentially executes actions ma1, ma2 and passes their outputs to f.

val lift3 : ('a1 -> 'a2 -> 'a3 -> 'r) -> 'a1 t -> 'a2 t -> 'a3 t -> 'r t

lift3 f ma1 ma2 ma3 sequentially executes actions ma1, ma2, ma3 and passes their outputs to f.

val lift4 : ('a1 -> 'a2 -> 'a3 -> 'a4 -> 'r) -> 'a1 t -> 'a2 t -> 'a3 t -> 'a4 t -> 'r t

lift4 f ma1 ma2 ma3 ma4 sequentially executes actions ma1, ma2, ma3, ma4 and passes their outputs to f.

val lift5 : ('a1 -> 'a2 -> 'a3 -> 'a4 -> 'a5 -> 'r) -> 'a1 t -> 'a2 t -> 'a3 t -> 'a4 t -> 'a5 t -> 'r t

lift5 f ma1 ma2 ma3 ma4 ma5 sequentially executes actions ma1, ma2, ma3, ma4, ma5 and passes their outputs to f.

val replicate : int -> 'a t -> 'a list t

replicate n a sequentially runs n times a.

  • raises Invalid_argument

    If n < 0.

Lexing

type token

The type of token in the finite stream being parsed.

val peek : token option t

peek state is (state', token_opt) where token_opt is the next unconsumed token in state. If token_opt = Option.None, then the end of the input stream was reached. Otherwise, token_opt = Option.Some token. The token is not consumed, meaning that state' is not advanced to the next token in the stream.

val observe : token option t

observed state is like peek state, but the observed token is consumed.

val accept : unit t

accept state is (state', ()) where state' is derived from state by consuming the next token in the input stream. This effectively observes and discards the next token in state.

val insert : token -> unit t

insert token state is (state', ()) where state' is derived from state by inserting token at the beginning of the input stream. That is, token is the next token in state'.

Locations

type location = Beluga_syntax.Location.t

The type of locations with which input tokens are annotated.

val next_location : location option t

next_location state is (state', next_location_opt) where next_location_opt is the location of the next token in state. This does not advance the input stream. next_location_opt = Option.None at the end of the input stream.

val previous_location : location option t

previous_location state is (state', previous_location_opt) where previous_location_opt is the location of the last token in state to have been consumed. previous_location_opt = Option.None at the beginning of the input stream.

Backtracking

val enable_backtracking : unit t

enable_backtracking state is (state', ()) where state' has backtracking enabled.

val disable_backtracking : unit t

enable_backtracking state is (state', ()) where state' has backtracking disabled.

val can_backtrack : bool t

can_backtrack state is (state', flag) where flag = true indicates that state and state' allow backtracking out of an erroneous result, and flag = false otherwise.

val allow_backtracking_on_error : ('a, 'e) Stdlib.result t -> ('a, 'e) Stdlib.result t

allow_backtracking_on_error m is m' such that m' state is (state', x) with backtracking enabled in state' if x = Result.Error cause. That is, this combinator enables backtracking if m' produces an error. Backtracking then needs to be manually disabled afterwards.

val with_checkpoint : ('a, 'e) Stdlib.result t -> ('a, [> `Backtracked of 'e | `Did_not_backtrack of 'e ]) Stdlib.result t

with_checkpoint m is m' such that m' state marks the current state, performs m, then either

  • discards the marked state if m state = (state', Result.Ok x),
  • backtracks to the marked state if m state = (state', Result.Error cause).

The output error from m is additionally annotated with whether backtracking occurred.

In the case of a parser m, backtracking can occur if backtracking is enabled with allow_backtracking_on_error, or if m did not consume any input.