[rust-dev] Polymorphism & default parameters in rust

[Emmanuel Surleau]

Hi,

I'm new to rust, and I'm struggling to find an elegant way to work with default
parameters.

I'm trying to implement in rust the equivalent of the following Python line:

def flag(self, name, desc, short_name=None, max_count=1, banner=None):
    ...

The idea is to offer a "simple" API (with only name and desc mandatory, while
making available number of advanced options if needed).

My first move was to try polymorphism:

fn a(x: ~str) -> ~str {
    #fmt("First function with %s", x)
}

fn a(x: ~str, y: ~str) -> ~str {
    #fmt("Second function with %s and %s", x, y)
}

fn main() {
    #info("Result: ");
}

Oddly enough, this compiles, but the first function is shadowed by the second,
so attempting a(~"something") does not compile. I assume this is not an intended
behaviour.

Further research hasn't turned any solution. Is there some idiomatic way in rust
of having defaults for parameters?

Cheers,

Emm