Operator overloading

Programming technique, in which some or all of operators like "+", "=" or "==" are treated as functions and can be defined or redefined for new types. Sometimes defining new operators is allowed. This is usually only a syntactic sugar, and it can be easily emulated by function calls:

With operator overloading	a + b * c
Without operator overloading	our_new_type_add (a, our_new_type_multiply (b,c))

Only in case when operators can be called implicitely they are of some use other than esthetics. This is the case with Ruby operator to_s, which returns object representation of string and with operators in PostgreSQL, where mathematical transformations can be defined on operators and PostgreSQL may use many optimalizations to expressions that use them.

Please add more languages to this list

Languages that support operator overloading and declaring new operators: PostgreSQL version of SQL Ruby

Languages that support operator overloading: Ada, C++, C#?

Languages that don't support operator overloading: C, Java, Pascal