[Haskell-cafe] Is () a 0-length tuple?

Deniz Dogan deniz.a.m.dogan at gmail.com
Sun Nov 8 16:48:51 EST 2009

2009/11/8 Matthew Gruen <wikigracenotes at gmail.com>:
> On Sun, Nov 8, 2009 at 6:21 AM, Deniz Dogan <deniz.a.m.dogan at gmail.com>
> wrote:
>> What point are you trying to make by distinguishing JSON from
>> JavaScript? JSON is a subset of JavaScript, they share the same type
>> system. "Null can be only one value." This doesn't make sense to me,
>> since as you say null is not a type, but a value.
>> --
>> Deniz Dogan
> It seems I underestimated the typedness of null in JavaScript :) I checked
> the ECMAScript specification, and it does refer to a "null type".. so titto
> was right.[1] My opinion is that JSON's 'type system' should be analyzed
> orthogonal to JavaScript's regardless. If JSON is a subset of JavaScript, it
> is primarily a syntactic one. When I said "Null can be only one value",
> implying that null is a type, I was referring to JSON's null, not
> JavaScript's null. In JSON, null *is* definitely a unit type. When
> considering mappings between Haskell and JSON in the case of (), we should
> see that () is a unit type in Haskell, null is a unit type in JSON
> (regardless of its role in JavaScript), and maybe try to associate them.
> —Matt
> [1] I was misled by the fact that typeof null = 'object'. The logic behind
> this, I think, is that null is meant to be bound to a variable that would
> otherwise be a reference to an actual object value. Many have criticized
> this result, e.g. Douglas Crockford
> (http://javascript.crockford.com/remedial.html)

Let's keep in mind when reading the ECMAScript specification that
JavaScript is merely based on it and breaks it on several different
points. :)

Deniz Dogan

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