Evaluation strategy

In a programming language, an evaluation strategy is a set of rules for evaluating expressions.^[1] The term is often used to refer to the more specific notion of a parameter-passing strategy^[2] that defines the kind of value that is passed to the function for each parameter (the binding strategy)^[3] and whether to evaluate the parameters of a function call, and if so in what order (the evaluation order).^[4] The notion of reduction strategy is distinct,^[5] although some authors conflate the two terms and the definition of each term is not widely agreed upon.^[6] A programming language's evaluation strategy is part of its high-level semantics. Some languages, such as PureScript, have variants with different evaluation strategies. Some declarative languages, such as Datalog, support multiple evaluation strategies.

The calling convention consists of the low-level platform-specific details of parameter passing.