scribblenauts is the game where you type in something and it appears.
scribblenauts is the game where you type in something and it appears.
game where you type in something and it appears?
scribblenauts
Na
Na
bullet::::1. polymorphism. some kinds of data are very generic. in particular, lisp is a "list programming language" where lists are data whose type can be a "list of something", e.g. a list of numbers. functions for such generic data types are often themselves generic. for instance, counting the number of items on a list is independent of the type of its items. however, a generic function that adds another item to a given list needs type checking to ensure that the list will remain consistent with respect to the type of its items. for example, that only numbers may be added to a list of numbers. types for such "generic" data and functions are called "polymorphic", meaning that they can be used for more than one type. the polymorphic function for adding an item can be used for a list of numbers as well as for a list of words or even a list of anything. more precisely, this kind of polymorphism is called parametric polymorphism, where "something" is the parameter in "list of something". more formally, "list of something" may be written codice_1 with codice_2 being the type parameter. the type of a function that adds a new item to a list is codice_3, meaning that for any and all types t the adding function needs an item of type t and a list-of-ts, to produce a resulting (new) list-of-ts. thus, the first challenge was to design a type system that properly expressed parametric polymorphism.
hindley–milner type system