the call-able(s) or string(s) to compose into one function
A new function f(x) that in turn returns fun[0](fun[1](...(x)))....
import std.algorithm.comparison : equal; import std.algorithm.iteration : map; import std.array : split; import std.conv : to; // First split a string in whitespace-separated tokens and then // convert each token into an integer assert(compose!(map!(to!(int)), split)("1 2 3").equal([1, 2, 3]));
Composes passed-in functions fun[0], fun[1], ....