Comment author: administrator

Hello,

Full_Name: Frederic Loulergue

Ocaml Manual indicates that :
~-3 could be written -3
~-3 could be written -.3

No. ~- and ~-. are prefix operators. When - and -. are used as prefix
operators
(instead of infix), the parser converts them to ~- and ~-. respectively.

This means that (- x) is the same as (- x),
and (-. x) is the same as (-. x).

but -3. is accepted and evaluated to -:float = -. 3.

Constants are another matter. -3. is a floating-point constant, not
the application of unary negation to a number. You see the difference when
using it in a pattern:

fun (-3.) -> true;; <- this works
fun (-~. 3.) -> true;; <- this doesn't work

If it is not a bug it is an ugly feature

The ugliness is in mathematics: using the same identifier for two different
functions: subtraction and negation. We are only propagating this ugliness
because of the principle of least astonishment.

-- Damien

Comment author: administrator

Constants are another matter. -3. is a floating-point constant, not
the application of unary negation to a number.

Euh oui ok j'ai honte.
Désolé du dérangement et merci pour la réponse.

Très cordialement,

FL