Criticism
One issue with duck typing is that it forces the programmer to have a much wider understanding of the code he or she is working with at any given time. In a strongly and statically typed language that uses type hierarchies and parameter type checking, it's much harder to supply an unexpected object type to a class. For instance, in Python, you could easily create a class called Wine, which expects a class implementing the "press" attribute as an ingredient. However, a class called Trousers might also implement the press method. With Duck Typing, in order to prevent strange, hard-to-detect errors, the developer needs to be aware of each potential use of the method "press", even when it's conceptually unrelated to what he or she is working on.
In essence, the problem is that, "if it walks like a duck and quacks like a duck", it could be a dragon doing a duck impersonation. You may not always want to let dragons into a pond, even if they can impersonate a duck.
Proponents of duck typing, such as Guido van Rossum, argue that the issue is handled by testing, and the necessary knowledge of the codebase required to maintain it.
Criticisms around duck typing tend to be special cases of broader points of contention regarding dynamically typed versus statically typed programming language semantics.
Read more about this topic: Duck Typing
Famous quotes containing the word criticism:
“The critic lives at second hand. He writes about. The poem, the novel, or the play must be given to him; criticism exists by the grace of other men’s genius. By virtue of style, criticism can itself become literature. But usually this occurs only when the writer is acting as critic of his own work or as outrider to his own poetics, when the criticism of Coleridge is work in progress or that of T.S. Eliot propaganda.”
—George Steiner (b. 1929)
“It is ... pathetic to observe the complete lack of imagination on the part of certain employers and men and women of the upper-income levels, equally devoid of experience, equally glib with their criticism ... directed against workers, labor leaders, and other villains and personal devils who are the objects of their dart-throwing. Who doesn’t know the wealthy woman who fulminates against the “idle” workers who just won’t get out and hunt jobs?”
—Mary Barnett Gilson (1877–?)
“However intense my experience, I am conscious of the presence and criticism of a part of me, which, as it were, is not a part of me, but a spectator, sharing no experience, but taking note of it, and that is no more I than it is you. When the play, it may be the tragedy, of life is over, the spectator goes his way. It was a kind of fiction, a work of the imagination only, so far as he was concerned.”
—Henry David Thoreau (1817–1862)