1.7 how to read haskell expressions

If you've read math before, it's essentially the same, but with a little more rules. $fx$ means applying a function $f$ to a value $x$, reading from left to right. So, be careful if you're doing $fxy$, as this is essentially $f(x)$ being applied to $y$, meaning $f(x)$ returns a function.

There are a few exceptions for certain operators, because otherwise Haskell would suck. Consider $+$. We want to write $x+y$, not $+xy.$ As for order of operations with this reframing, operators happen after function calls, meaning $pq+rs$ is the same as $p(q)+r(s)$, instead of $p(q+r)(s)$. The other operator which this is useful for is composition $\circ$:

f . g = (.) f g -- f(g) should return a function
(f . g) x = (.) f g x -- f(g(x))
f . g x = f . (g x) -- expects g(x) to be a function