Inspired from the assortment of other 'Tips for golfing in language xyz'. As usual, please only suggest tips that are specific to OCaml and not programming in general. One tip per answer please.
4 Answers
Use functions instead of match
let rec f=function[]->0|_::t->1+f t
is shorter than
let rec f x=match x with[]->0|_::t->1+f t
Never use begin […] end
This:
begin […] end
is always synonymous with this:
([…])
Define several variables or functions at once
Thanks to tuples, you can define several variables at once. And as functions are first-class citizens…:
let f,g=(fun x->x+1),fun x->2*x
You can’t, however, write:
let f,g=(fun x->x+1),fun x->2*f x
Error: Unbound value f
Unfortunately, you can’t avoid the issue by using rec
:
let rec f,g=(fun x->x+1),fun x->2*f x
Error: Only variables are allowed as left-hand side of
let rec
Exploit curryied functions
Functions in OCaml are curryied. It might be useful to exploit that fact sometimes.
let n y=f x y
can be written
let n=f x
If you need arithmetic operations, you can surround them with parentheses so they behave like standard, prefix functions. (+)
, (-)
, …
let n=(+)1;;
n 3;;
- : int = 4