ct.zig

const std = @import("std");

fn stringForUnsigned(comptime value: usize) []const u8 {
    if (value == 0) return "0";

    const base = 10;
    const base_digits = "0123456789";
    const ndigits = 1 + @floatToInt(
        usize,
        std.math.floor(std.math.log2(@intToFloat(f64, value)) / std.math.log2(@intToFloat(f64, base))),
    );
    comptime var buffer: [ndigits]u8 = undefined;
    comptime var i = buffer.len;
    comptime var a = value;
    inline while (i > 0 and a != 0) {
        i -= 1;
        const digit = a % base;
        buffer[i] = base_digits[digit];
        a /= base;
    }

    return &buffer;
}

export fn foo() void {
    @compileError("whups: " ++ stringForUnsigned(98137123));
}