Haskell function composition (.) and function application ($) idioms: correct use.
- by Robert Massaioli
I have been reading Real World Haskell and I am nearing the end but a matter of style has been niggling at me to do with the (.) and ($) operators.
When you write a function that is a composition of other functions you write it like:
f = g . h
But when you apply something to the end of those functions I write it like this:
k = a $ b $ c $ value
But the book would write it like this:
k = a . b . c $ value
Now to me they look functionally equivalent, they do the exact same thing in my eyes. However, the more I look, the more I see people writing their functions in the manner that the book does: compose with (.) first and then only at the end use ($) to append a value to evaluate the lot (nobody does it with many dollar compositions). Is there a reason for using the books way that is much better than using all ($) symbols? Or is there some best practice here that I am not getting? Or is it superfluous and I shouldn't be worrying about it at all? Thanks.
