Setoid example

[chamini2]

The example of setoid uses equality between the elements of the array but it assumes there's an equality operator (==) between the elements of the setoid.

I would do the following:

Number.prototype.equals = function(num) {
  return num.valueOf() === this.valueOf();
}

(2).equals(2) // true
(2).equals(3) // false

Array.prototype.equals = function(arr) {
    var len = this.length
    if (len !== arr.length) {
        return false
    }
    for (var i = 0; i < len; i++) {
        if (! this[i].equals(arr[i])) {
            return false
        }
    }
    return true
}


[1,2].equals([1,2]) // true
[1,2].equals([1,2,3]) // false
[1,2].equals([2,3]) // false

[jethrolarson]

Yeah. It's too bad you have to keep defining your own equality function for everything in JS. Especially since it's generally considered a bad practice to modify native prototypes.

[chamini2]

I think that the examples are written in JS to make it easier to understand, but they're not the best practices nor intended to be. They're just to clarify any doubt left in the description of the functional programming term.

[jethrolarson]

I think the code we display should be moderately practical. It can be
incomplete or have uncovered cases. But people should be able to copy it

On Wed, Jul 27, 2016, 5:23 AM Matteo Ferrando notifications@github.com
wrote:

I think that the examples are written in JS to make it easier to
understand, but they're not the best practices nor intended to be.
They're just to clarify any doubt left in the description of the functional
programming term.

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[chamini2]

Well, this is code that can be copied.