Re: override to!string

[Dmitry Olshansky]

On 25.02.2011 17:28, spir wrote:
Hello,
Imagine I have the following custom type:
    alias float[] Numbers;

Is it possible to override to!string for Numbers so that it outputs eg 
like;
    (1.1 2.2 3.3)
?

I can indeed override/specialise toImpl or formatValue for the custom 
type, but those overrides are simply ignored (tested).

Denis

First things first, it's just an alias and not a custom type. So 
compiler won't distinguish between float[] and Numbers at all.
The obvious way around is make your own thin wrapper, but yeah, it won't 
get format specifiers until writeTo or similar proposal implemented.

import std.stdio,std.conv;
struct Numbers{
    float[] data;
    string  toString(){
        string result = "(";
        foreach(val;data[0..$-1]){
            result ~= to!string(val);
            result ~= ' ';
        }
        result ~= to!string(data[$-1]);
        result ~= ')';
        return result;
    }
    alias data this;
}

Usage:
void main(){
    Numbers nums = Numbers([1.1,2.2,3.3]);
    writefln("%s",nums);
    nums[0] = 4.4;
    writefln("%s",nums);
}

--
Dmitry Olshansky