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First-class functions: Difference between revisions
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→{{header|D}}: correction
(→{{header|Ursala}}: Marked incorrect. Cube/cube root seem to be built-in or library functions rather than "user-created".) |
m (→{{header|D}}: correction) |
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=={{header|D}}==
'''D 2.0 version''' of compose function (template).
<lang D>import std.stdio;
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Example:
<lang D>
import std.stdio ;
auto sinwrp = delegate (real x){ return sin(x);};▼
auto coswrp = delegate (real x){ return cos(x);};▼
auto sincos_n = delegate (real x) { return sin(cos(x)); };▼
T delegate(S) compose(T, U, S)(T delegate(U) f, U delegate(S) g) {
return (S s) {
}
void main() {
// warper need as not all built-in real functions
// have same signature , eg pure/nothrow
auto acos = delegate (real x) { return std.math.acos(x) ; } ;
auto cube = delegate (real x) { return x*x*x ; } ;
auto cbrt = delegate (real x) { return std.math.cbrt(x) ; } ;
// built-in : sin/cos/asin/acos/cbrt user:cube
auto fun = [sin, cos, cube] ;
auto inv = [asin, acos, cbrt] ;
foreach(i, f ; fun)
writefln("%6.3f", compose(f, inv[i])(0.5)) ;
}</lang>
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