Hello, I'm trying to implement a scala concept partial application in
which one can chains pattern matching function. If the first failed, the
second is tried.
It seems it is impossible to give an exception as argument to a function.
exception Nothing;;
let (|||) a b = try a
with
| Nothing
This behavior is expected given than OCaml is strict, and your operator
||| would be an ordinary function (unlike || and ). You have to use
either functions (or lazy values) instead of expressions, or options
instead of exceptions.
Tiphaine
Le 17/02/2012 19:16, Pierre-Alexandre Voye a écrit :
Here is an example of giving an exception as an argument to a function:
let run_or ~cmd ~err = if Sys.command cmd 0 then raise err
and an example usage:
let config_fail = Failure (Could not configure ^ p.id) in
run_or ~cmd:(sh configure ^ config_opt) ~err:config_fail;
The problem with your
The arguments are evaluated before being passed to the function.
So in your first test, Nothing is raised before even entering |||.
In the second case you're circumventing this by copying directly raise
Nothing in the body of the function: this copy-pasting is not
equivalent since you now force
