import std.range;

import std.algorithm;

import std.stdio;

import std.typecons;

​

auto splitBy(alias F, R)(R range) 

if (isInputRange!R)

{

    import std.functional : binaryFun;

    alias fun = binaryFun!F;

    return range

    .map!(x => tuple(x, true))

    .cumulativeFold!((a,b) => tuple(b[0], !((!fun(a[0],b[0])) ^ a[1])))

    .chunkBy!((a,b) => a[1] == b[1])

    .map!(x => x.map!(y => y[0]));

}

​

void main()

{

    [1,2,3,5,10,11,12,13,20,21,100].splitBy!"a+1 != b"().writeln;

}