Rosetta Code

First-class functions: Difference between revisions

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Added output example
Javascript cleaned up using Scala as an inspiration
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=={{header|JavaScript}}==
<lang javascript>// Functions as values of a variable
{{incomplete|JavaScript|Fails to demonstrate that the result of applying the composition of each function in A and its inverse in B to a value, is the original value}}
var cube = function(x) {
assuming the print function is provided by the environment, like a stand-alone shell. In browsers, use alert(), document.write() or similar
return Math.pow(x, 3);
 
};
<lang javascript>var compose = function (f, g) { ▼
var cuberoot return= function (x) {
return f(gMath.pow(x), 1/3);
}; ▼
};
 
// Higher order function
var fn = [Math.sin, Math.cos, function (x) { return Math.pow(x, 3); }];
▲<lang javascript>var compose = function (f, g) {
var inv = [Math.asin, Math.acos, function (x) { return Math.pow(x, 1/3); }];▼
( return function (x) { ▼
return f(g(x));
▲ };
};
 
// Storing functions in a array
▲(function () {
var fun = [Math.sin, Math.cos, cube];
for (var i = 0; i < 3; i++) {▼
▲var inv = [Math.asin, Math.acos, function (x) { return Math.pow(x, 1/3); }cuberoot];
var f = compose(inv[i], fn[i]);▼
print(f(0.5)); // 0.5
}
})();
 
▲ for (var i = 0; i < 3; i++) {
</lang>▼
// Applying the composition to 0.5
▲ var f = console.log(compose(inv[i], fnfun[i])(0.5));
▲}</lang>
Output:
<pre>0.5
0.4999999999999999
0.5</pre>
 
=={{header|Lua}}==
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