operator overloading + - / * = etc...

[Leif K-Brooks]

Paul Rubin wrote:
> The symbols on the left side of = signs are called variables even in
> Haskell, where they don't "vary" (you can't change the value of a
> variable once you have set it).

FWIW, that's the original, mathematical meaning of the word 'variable'. 
They _do_ vary, but only when you call the function with different 
arguments (which happens frequently in Haskell, which uses recursion in 
place of loops).