Return the sum of f(i) from i=k, k+1, ... till p(i) holds true or 0

This is a tail recursive implementation.

Usage

summa(f, k, p)

Arguments

f

A function (named, anonymous or formula).

k

an integer index.

p

A function (named, anonymous or formula).

Value

a number

Examples

if (FALSE) {
# sum of squares integers less than or equal to 4
summa(\(x) x**2, 1, \(i) i<=4)
}