[Issue 5550] std.range.enumerate()

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=5550



--- Comment #2 from bearophile_hugs at eml.cc 2012-03-26 17:20:14 PDT ---
The problem was caused by the alias this. This avoids the problem:


import std.stdio, std.algorithm, std.range, std.typecons, std.traits,
std.array;

struct Enumerate(R) {
    R r;
    int i;

    @property bool empty() {
        return this.r.empty;
    }

    @property Tuple!(typeof(this.i), typeof(R.init.front)) front() {
        return typeof(return)(i, this.r.front);
    }

    void popFront() {
        this.r.popFront();
        this.i++;
    }
}

Enumerate!R enumerate(R)(R range, int start=0) if (isInputRange!R) {
    return Enumerate!R(range, start);
}

void main() {
    auto flags = [0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1];

    flags.enumerate(2).filter!q{!a[1]}().map!q{a[0]}().writeln();
}


The last line is noisy but it's readable.

This is less noisy but longer:

flags.enumerate(2).filter!(t => !t[1])().map!(t => t[0])().writeln();

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------