How does type checking in Erlang compare to Java/Python/C/C++/Haskell?
Erlang itself, i.e. ignoring the Dialyzer, uses a dynamic type system. All type checking is done at run-time, the compiler does not check types at compile time. The run-time type system cannot be defeated. This is comparable to the type systems in Lisp, Smalltalk, Python, Javascript, Prolog and others. Java, Eiffel and some other languages have type systems which are mostly checked at compile time, but with some remaining checking done at run time. The combination of checking cannot be defeated. Such type systems provide some guarantees about types which can be exploited by the compiler, this can be useful for optimisation. Haskell, Mercury and some other languages have type systems which are completely checked at compile time. This type system cannot be defeated. The type system in this type of language is also a design tool, it increases the language’s expressiveness. C, pascal and C++ have type systems which are checked at compile time, but can be defeated by straightforward means p
