Re: [Haskell-cafe] Origins of '$'

On Sun, Dec 7, 2008 at 2:05 AM, Hans Aberg wrote:

As for the operator itself, it appears in Alonzo Church, "The Calculi of Lambda-Conversion", where it is written as exponentiation, like x^f

That's reminiscent of the notation in Lambek and Scott where (roughly speaking) the function converting an element of an object A^B to an arrow B->A (something Haskellers don't normally have to think about) is written as a superscript integral sign. Presumably this comes from the same source. Both $ and the integral sign are forms of the letter 's'. Don't know why 's' would be chosen though. -- Dan