Let $S$ be a set of numbers in $\mathbb N$.
Let us define two functions:
SumLessThan10 that returns 1, if the sum of the elements of $S$ is 9 or fewer and 0, if the sum is greater than 10.
Mean that calculates the arthimetic mean of $S$.
Let us assume we have some iteration for calculating the sum and the mean (is there another way of doing it?), then for
SumLessThan10, as soon as the sum reaches 10 (if it does), we can finish the calculation; we don't need to necessarily iterate through the whole set of $S$.
ii) In order to calculate the mean, we must iterate through the whole set of $S$, we cannot use 'lazy-evaluation'.
Is there a name for functions that can (always/ sometimes) be lazily-evaluated in this way, to distinguish them from functions that must be run over all elements in a set in order to get the result?