Functions

Functions are first class values. They can be stored in variables, in data structures, and they can be passed around to other functions. Etc. They are defined with the syntax,

|arg0, arg1, ...| body

This is often combined with a let bind to make a named function.

let f = |x, y| x + y + 1

f is now bound to the lambda that adds it’s two arguments and 1. You can also use structure patterns in function arguments as long as the pattern will always match.

let g =|(x, y), z| x + y + z

Type annotations can be used to constrain the argument types and the return type,

let g = |(x, y): (f64, f64), z: f64| -> f64 x + y + z

Functions are called with the following syntax.

f(1, 1)

Would return 3. A function stored in a data structure is called the same way, s.f(1, 1) calls the function f in the struct s.