diff options
| author |  Arnaud Spiwack <arnaud@spiwack.net> | 2014-10-23 15:42:07 +0200 |
|---|---|---|
| committer | Arnaud Spiwack <arnaud@spiwack.net> | 2014-10-23 16:02:45 +0200 |
| commit | 279ce5a03cb39b6a7fd596e5d339b6f825d03512 (patch) | |
| tree | 50b20dfde2ca48d938422489027bc5de0e43c3ee /lib | |
| parent | 4cb05fc1afaf938d1b36e0c00226ff173e2d8f22 (diff) | |
Monad: change the error managing of two-list combinators.
Otherwise I risked catching errors from the argument functions when I wanted to catch size mismatch to add information to errors.
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/monad.ml | 16 | ||||
| -rw-r--r-- | lib/monad.mli | 13 |
2 files changed, 9 insertions, 20 deletions
diff --git a/lib/monad.ml b/lib/monad.ml index bc58c4d17..4a52684da 100644 --- a/lib/monad.ml +++ b/lib/monad.ml @@ -67,16 +67,11 @@ module type ListS = sig (** {6 Two-list iterators} *) - (** Raised when an combinator expects several lists of the same size - but finds that they are not. Exceptions must be raised inside - the monad, so two-list combinators take an extra argument to - raise the exception. *) - exception SizeMismatch - (** [fold_left2 r f s l1 l2] behaves like {!fold_left} but acts - simultaneously on two lists. Returns [r SizeMismatch] if both lists - do not have the same length. *) - val fold_left2 : (exn->'a t) -> + simultaneously on two lists. Runs [r] (presumably an + exception-raising computation) if both lists do not have the + same length. *) + val fold_left2 : 'a t -> ('a -> 'b -> 'c -> 'a t) -> 'a -> 'b list -> 'c list -> 'a t end @@ -143,7 +138,6 @@ module Make (M:Def) : S with type +'a t = 'a M.t = struct | a::b::l -> f a >> f b >> iter f l - exception SizeMismatch let rec fold_left2 r f x l1 l2 = match l1,l2 with @@ -153,7 +147,7 @@ module Make (M:Def) : S with type +'a t = 'a M.t = struct f x a1 b1 >>= fun x' -> f x' a2 b2 >>= fun x'' -> fold_left2 r f x'' l1 l2 - | _ , _ -> r SizeMismatch + | _ , _ -> r end diff --git a/lib/monad.mli b/lib/monad.mli index a6be1df7a..c8655efa0 100644 --- a/lib/monad.mli +++ b/lib/monad.mli @@ -69,16 +69,11 @@ module type ListS = sig (** {6 Two-list iterators} *) - (** Raised when an combinator expects several lists of the same size - but finds that they are not. Exceptions must be raised inside - the monad, so two-list combinators take an extra argument to - raise the exception. *) - exception SizeMismatch - (** [fold_left2 r f s l1 l2] behaves like {!fold_left} but acts - simultaneously on two lists. Returns [r SizeMismatch] if both lists - do not have the same length. *) - val fold_left2 : (exn->'a t) -> + simultaneously on two lists. Runs [r] (presumably an + exception-raising computation) if both lists do not have the + same length. *) + val fold_left2 : 'a t -> ('a -> 'b -> 'c -> 'a t) -> 'a -> 'b list -> 'c list -> 'a t end |