Monads compared to InputRanges?

[Shammah Chancellor]

I'm not particularly familiar with the syntax being used in the variet 
of monad examples.   I'm trying to figure out how this is different 
from UFCS on InputRanges.   It seems like std.algorithm implements 
something which accomplished the same thing, but much easier to 
understand?

Can somebody maybe do a compare and contrast for me?
-Shammah