< programming > Any piece of program code in a high-level language which, when (if) its execution terminates, returns a value. In most programming languages, expressions consist of constants, variables, operators, functions, and parentheses . The operators and functions may be built-in or user defined. Languages differ on how expressions of different types may be combined - with some combination of explicit casts and implicit coercions .
The syntax of expressions generally follows conventional mathematical notation, though some languages such as Lisp or Forth have their own idiosyncratic syntax.
(2001-05-14)