> A total function is a function that is defined over the entire domain of its > inputs. For example, addition is a total function over integers, because > for every possible pair of integers you pass to it there is a logical return > value. However, square root is not a total function over integers because > there are some integers you pass it for which there is not representable > return value. (Negative numbers, unless you get into imaginary numbers > which PHP doesn't support.) In those cases, you have to throw an exception > or return an error code or similar.
Maybe nitpicking, but PHP-land shouldn't make up their own definitions: "A total function is a function that is defined for all possible values of its input. That is, it terminates and returns a value." https://softwareengineering.stackexchange.com/questions/334874/in-the-context-of-functional-programming-what-are-total-functions-and-partia Which means a total function is guaranteed to not have any errors, like exceptions or division by zero. Compare with languages F* or Koka which support this notation. I get your point tho. :) Olle -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: https://www.php.net/unsub.php
