Error on is_sorted & is_sorted_until

[samchon]

Summary

• TSTL Version: 2.1.2
• Expected behavior: is_sorted & is_sorted_until requires only comparator like less
• Actual behavior: They require not only comparator but also predicator (equal_to)

Code occuring the bug

Functions is_sorted and is_sorted_until returns invalid value when target elements are not atomic values but custom objects that have not defined the predicator (Object.equals) function.

import std = require("tstl");

function comparator(x: std.IPointer<number>, y: std.IPointer<number>): boolean
{
    return x.value < y.value;
}
function main(): void
{
    let pointers: std.Vector<std.IPointer<number>> = new std.Vector();
    for (let i: number = 0; i < 100; ++i)
        pointers.push_back({ value: std.randint(0, 10) });

    std.sort(pointers.begin(), pointers.end(), comparator);
    console.log( std.is_sorted(pointers.begin(), pointers.end(), comparator) );
        // MUST BE true
        // BUT PRINTS false
}
main();

[samchon]

tstl/src/algorithm/sorting.ts

Line 227 in 0aadfd3

if (!(equal_to(next.value, first.value) || comp(first.value, next.value)))

Functions is_sorted and is_sorted_until are using equal_to function. However, those functions do not provide the matched predicator function. The equal_to must be replaced to !comp(x, y) && !comp(y, x).

[samchon]

Fixed on v2.1.3 patch