Functional

Helpers for functional style programming

Backwards Curry

Curry

This allows partial function application by wrapping the passed function f in two lambdas. This provides a limited form of Currying.

When a function is wrapped with c the first time you call it, it will return a new function with the arguments you supplied already applied. So that

c(f) = f'
f'(a, b, ...) = f''
f''(u, v, ...) = f(a, b, ..., u, v, ...)

where "a, b, ..." and "u, v, ..." are lists of arbitrary variables.

Examples

Classic currying example:

add(x, y) = x + y
add2(y) = c(add)(2)

This is useful when chaining operations due to limitations of the do-syntax and the chain operator |>:

cmap = c(map)
cfilter = c(filter)

1:10 |> cmap() do x
    x^2
end |> cfilter() do x
    x > 50
end

Note that functions like cmap are generally already defined by this module.

Do fn(val) if cond(val) else nothing

If the condition is true then returns the result of fn(val) otherwise returns nothing. This can be chained with cdefault to provide a default value when cond(val) is false.