[ljouhet]

First line of https://t3x.org/klong/prime.html

"The braces around an expression denote a function. Because this function contains a single variable, x, it is a monadic function or a monad."

I never understood that about monads, even if it's litterally their name.

[kragen]

A monadic function in APL-family languages is not related to monads from category theory, which are the ones you see in Haskell, nor to Leibniz's monads.

[kazinator]

In this context it just means "one parameter function".

It looks like every apparently free variable in a Klong brace expression is actually bound as a function parameter.

This is so in basic algebra in that we can think of, say, x^2 + y^2 as a two parameter function, even without writing out the full f(x, y) = x^2 + y^2 notation with the f(x, y) head.

A two parameter function would be called "dyadic" in the jargon which calls one argument functions "monadic".