types.classof

from "types" import classof

Returns the class that obj belongs to.

Parameters

Return value

For an instance, its own defining class - the exact class it was constructed from, not a common ancestor. For anything else, including a class value itself, the built-in class object for obj's type: types.Integer, types.Float, types.Bool, types.String, types.Array, types.Table, types.Function (for both a script closure and a native closure), types.Generator, types.Thread, types.Class, types.WeakRef, types.UserData or types.Null.

types.Instance is never returned this way: a plain instance always maps to its own defining class instead of that placeholder built-in class.

Notes

Like type, classof ignores metamethods: it never calls _typeof, so a class that defines _typeof has no effect on it. Unlike type, which reports every instance with the same string "instance", classof returns the actual class, so it can tell one class of instance from another. Unlike typeof, whose result a class can change by defining _typeof, classof always returns the real class object read straight from obj.

Marked pure because the result depends only on obj.

Example

let types = require("types")

class Animal {
  function _typeof() { return "custom-typeof" }
}
let a = Animal()

println(types.classof(a) == Animal)           // an instance's own class
println(types.classof(Animal) == types.Class) // a class is itself of class Class
println(types.classof(5) == types.Integer)
println(type(a))  // "instance": type() ignores _typeof
println(typeof a)  // "custom-typeof": typeof calls _typeof

true
true
true
instance
custom-typeof

See also