On 07/09/13 22:11, Renato Lenzi wrote:
Is it possibile, or will be possibile, to use default parameters
and/or named parameters in Rust?
In the docs i couldn't find anything about this (may be my fault...)
Regards.
It is not possible currently, but there's an open bug [6973] and with
(quite) a bit of discussion. Two current methods for simulating them
would be defining wrapper functions for the common shortcuts, or passing
the default/named args as a struct and use a "functional record update"
(FRU), e.g.
struct FooArgs {
x: int,
y: int,
z: int,
}
static DEFAULT_FOO: FooArgs = FooArgs { x: 1, y: 2, z: 3 };
/// a, b are compulsory, anything in rest is a default arg
fn foo(a: uint, b: uint, rest: FooArgs) { ... }
fn main() {
// only defaults
foo(10, 100, DEFAULT_FOO);
// y = -3, defaults for the rest
foo(10, 100, FooArgs { y: -3, .. DEFAULT_FOO }) // `..` indicates
an FRU
}
This one is unfortunately ugly, but it seems to get the job done.
Huon
[6973]: https://github.com/mozilla/rust/issues/6973
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