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avoid inheritance
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@davidchambers
davidchambers committed Jun 9, 2017
1 parent 5c80840 commit cd8a8c5
Showing 1 changed file with 47 additions and 28 deletions.
75 changes: 47 additions & 28 deletions index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -140,10 +140,10 @@
//. > Pair(1, 2)
//. Pair(1, 2)
//. ```
function Pair(a, b) {
if (!(this instanceof Pair)) return new Pair(a, b);
this.a = a;
this.b = b;
function Pair(fst, snd) {
if (!(this instanceof Pair)) return new Pair(fst, snd);
this.fst = fst;
this.snd = snd;
}

//# Pair.@@type :: String
Expand All @@ -164,7 +164,7 @@
//. false
//. ```
Pair.prototype['fantasy-land/equals'] = function equals(other) {
return Z.equals(this.a, other.a) && Z.equals(this.b, other.b);
return Z.equals(this.fst, other.fst) && Z.equals(this.snd, other.snd);
};

//# Pair#fantasy-land/lte :: (Ord a, Ord b) => Pair a b ~> Pair a b -> Boolean
Expand All @@ -180,21 +180,17 @@
//. false
//. ```
Pair.prototype['fantasy-land/lte'] = function lte(other) {
return Z.lte(this.a, other.a) && Z.lte(this.b, other.b);
return Z.lte(this.fst, other.fst) && Z.lte(this.snd, other.snd);
};

function makePair(p, a, b) {
return p instanceof Identity ? Identity(b) : Pair(a, b);
}

//# Pair#fantasy-land/compose :: Pair a b ~> Pair b c -> Pair a c
//.
//. ```javascript
//. > Z.compose(Pair('b', true), Pair(1, 'a'))
//. Pair(1, true)
//. ```
Pair.prototype['fantasy-land/compose'] = function compose(other) {
return makePair(this, this.a, other.b);
return Pair(this.fst, other.snd);
};

//# Pair#fantasy-land/concat :: (Semigroup a, Semigroup b) => Pair a b ~> Pair a b -> Pair a b
Expand All @@ -204,8 +200,7 @@
//. Pair([1, 2, 3, 4, 5, 6], [6, 5, 4, 3, 2, 1])
//. ```
Pair.prototype['fantasy-land/concat'] = function concat(other) {
return makePair(this,
Z.concat(this.a, other.a), Z.concat(this.b, other.b));
return Pair(Z.concat(this.fst, other.fst), Z.concat(this.snd, other.snd));
};

//# Pair#fantasy-land/map :: Pair a b ~> (b -> c) -> Pair a c
Expand All @@ -215,7 +210,7 @@
//. Pair('hello', 8)
//. ```
Pair.prototype['fantasy-land/map'] = function map(f) {
return makePair(this, this.a, f(this.b));
return Pair(this.fst, f(this.snd));
};

//# Pair#fantasy-land/ap :: Semigroup a => Pair a b ~> Pair a (b -> c) -> Pair a c
Expand All @@ -225,7 +220,7 @@
//. Pair('hello there', 8)
//. ```
Pair.prototype['fantasy-land/ap'] = function ap(other) {
return makePair(this, Z.concat(this.a, other.a), other.b(this.b));
return Pair(Z.concat(this.fst, other.fst), other.snd(this.snd));
};

//# Pair#fantasy-land/reduce :: Pair a b ~> ((c, a) -> c, c) -> c
Expand All @@ -235,7 +230,7 @@
//. [1, 2, 3, 4, 5, 6]
//. ```
Pair.prototype['fantasy-land/reduce'] = function reduce(f, x) {
return f(x, this.b);
return f(x, this.snd);
};

//# Pair#fantasy-land/traverse :: Applicative f => Pair a b ~> (TypeRep f, b -> f c) -> f (Pair a c)
Expand All @@ -246,9 +241,7 @@
//. ```
Pair.prototype['fantasy-land/traverse'] = function traverse(typeRep, f) {
var pair = this;
return Z.map(function(x) {
return makePair(pair, pair.a, x);
}, f(pair.b));
return Z.map(function(x) { return Pair(pair.fst, x); }, f(pair.snd));
};

//# Pair#fantasy-land/extend :: Pair a b ~> (Pair a b -> c) -> Pair a c
Expand All @@ -258,7 +251,7 @@
//. Pair('forever', 100)
//. ```
Pair.prototype['fantasy-land/extend'] = function extend(f) {
return makePair(this, this.a, f(this));
return Pair(this.fst, f(this));
};

//# Pair#fantasy-land/extract :: Pair a b ~> () -> b
Expand All @@ -268,7 +261,7 @@
//. 42
//. ```
Pair.prototype['fantasy-land/extract'] = function extract() {
return this.b;
return this.snd;
};

//# Pair#toString :: Pair a b ~> () -> String
Expand All @@ -278,7 +271,7 @@
//. 'Pair(1, 2)'
//. ```
Pair.prototype.toString = function toString() {
return 'Pair(' + Z.toString(this.a) + ', ' + Z.toString(this.b) + ')';
return 'Pair(' + Z.toString(this.fst) + ', ' + Z.toString(this.snd) + ')';
};

//# fst :: Pair a b -> a
Expand All @@ -288,7 +281,7 @@
//. 'hello'
//. ```
function fst(p) {
return p.a;
return p.fst;
}

//# snd :: Pair a b -> b
Expand Down Expand Up @@ -326,9 +319,8 @@
//. ```
function Identity(value) {
if (!(this instanceof Identity)) return new Identity(value);
Pair.call(this, Unit, value);
this.value = value;
}
Identity.prototype = Object.create(Pair.prototype);

//# Identity.@@type :: String
//.
Expand All @@ -355,6 +347,9 @@
//. > Z.equals(Identity([1, 2, 3]), Identity([3, 2, 1]))
//. false
//. ```
Identity.prototype['fantasy-land/equals'] = function equals(other) {
return Z.equals(this.value, other.value);
};

//# Identity#fantasy-land/lte :: Ord a => Identity a ~> Identity a -> Boolean
//.
Expand All @@ -368,27 +363,39 @@
//. > Z.lte(Identity(1), Identity(0))
//. false
//. ```
Identity.prototype['fantasy-land/lte'] = function lte(other) {
return Z.lte(this.value, other.value);
};

//# Identity#fantasy-land/concat :: Semigroup a => Identity a ~> Identity a -> Identity a
//.
//. ```javascript
//. > Z.concat(Identity([1, 2, 3]), Identity([4, 5, 6]))
//. Identity([1, 2, 3, 4, 5, 6])
//. ```
Identity.prototype['fantasy-land/concat'] = function concat(other) {
return Identity(Z.concat(this.value, other.value));
};

//# Identity#fantasy-land/map :: Identity a ~> (a -> b) -> Identity b
//.
//. ```javascript
//. > Z.map(Math.sqrt, Identity(64))
//. Identity(8)
//. ```
Identity.prototype['fantasy-land/map'] = function map(f) {
return Identity(f(this.value));
};

//# Identity#fantasy-land/ap :: Identity a ~> Identity (a -> b) -> Identity b
//.
//. ```javascript
//. > Z.ap(Identity(Math.sqrt), Identity(64))
//. Identity(8)
//. ```
Identity.prototype['fantasy-land/ap'] = function ap(other) {
return Identity(other.value(this.value));
};

//# Identity#fantasy-land/chain :: Identity a ~> (a -> Identity b) -> Identity b
//.
Expand All @@ -397,7 +404,7 @@
//. Identity(100)
//. ```
Identity.prototype['fantasy-land/chain'] = function(f) {
return f(this.b);
return f(this.value);
};

//# Identity#fantasy-land/alt :: Alt a => Identity a ~> Identity a -> Identity a
Expand All @@ -407,7 +414,7 @@
//. Identity([1, 2, 3, 4, 5, 6])
//. ```
Identity.prototype['fantasy-land/alt'] = function(other) {
return Identity(Z.alt(this.b, other.b));
return Identity(Z.alt(this.value, other.value));
};

//# Identity#fantasy-land/reduce :: Identity a ~> ((b, a) -> b, b) -> b
Expand All @@ -416,27 +423,39 @@
//. > Z.reduce(Z.concat, [1, 2, 3], Identity([4, 5, 6]))
//. [1, 2, 3, 4, 5, 6]
//. ```
Identity.prototype['fantasy-land/reduce'] = function reduce(f, x) {
return f(x, this.value);
};

//# Identity#fantasy-land/traverse :: Applicative f => Identity a ~> (TypeRep f, a -> f b) -> f (Identity b)
//.
//. ```javascript
//. > Z.traverse(Array, x => [x, x], Identity(0))
//. [Identity(0), Identity(0)]
//. ```
Identity.prototype['fantasy-land/traverse'] = function traverse(typeRep, f) {
return Z.map(Identity, f(this.value));
};

//# Identity#fantasy-land/extend :: Identity a ~> (Identity a -> b) -> Identity b
//.
//. ```javascript
//. > Z.extend(identity => Z.extract(identity) + 1, Identity(99))
//. Identity(100)
//. ```
Identity.prototype['fantasy-land/extend'] = function extend(f) {
return Identity(f(this));
};

//# Identity#fantasy-land/extract :: Identity a ~> () -> a
//.
//. ```javascript
//. > Z.extract(Identity(42))
//. 42
//. ```
Identity.prototype['fantasy-land/extract'] = function extract() {
return this.value;
};

//# Identity#toString :: Identity a ~> () -> String
//.
Expand All @@ -445,7 +464,7 @@
//. 'Identity([1, 2, 3])'
//. ```
Identity.prototype.toString = function() {
return 'Identity(' + Z.toString(this.b) + ')';
return 'Identity(' + Z.toString(this.value) + ')';
};

return {
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