module Exception:Exception is a purely functional replacement of OCaml's built-in exceptions.sig
..end
To indicate a normal value use Exception.return
. For
exceptional conditions use Exception.throw
. Function
Exception.catch
splices in an exception handler into the
thread of control. Execute an exception monad with
Exception.run
.
type ('a, 'b)
t
'left
is the exception's type and
'right
is the normal value's type.val bind : ('a, 'b) t -> ('b -> ('a, 'c) t) -> ('a, 'c) t
bind a_monad a_function
Apply a_function
to a_monad
producing another monad.
a_function
takes a normal value as argument and returns a
monad.
val return : 'a -> ('b, 'a) t
return a_normal_value
Answer a_normal_value
.
val throw : 'a -> ('a, 'b) t
throw an_exception
Answer an_exception
, or in other words, throw an_exception
.
val catch : ('a, 'b) t -> ('a -> ('c, 'b) t) -> ('c, 'b) t
catch a_monad an_exception_handler
Catch exceptions from a_monad
and feed them into
an_exception_handler
. an_exception_handler
takes an
exceptional value as argument and returns a monad.
val run : ('a -> 'b) -> ('c -> 'b) -> ('a, 'c) t -> 'b
run a_failure_function a_success_function a_monad
Run a_monad
. If a_monad
does not Exception.throw
an
exception, pass the result of evaluating the monad to
a_success_function
. Otherwise, if the a_monad
throws, pass
the exception to a_failure_function
.