Ad
related to: call by value explanation
Search results
Results From The WOW.Com Content Network
In programming language theory, call-by-push-value (CBPV) is an intermediate language that embeds the call-by-value (CBV) and call-by-name (CBN) evaluation strategies.
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 ...
In case of call by value, what is passed to the function is the value of the argument – for example, f(2) and a = 2; f(a) are equivalent calls – while in call by reference, with a variable as argument, what is passed is a reference to that variable - even though the syntax for the function call could stay the same. [5]
These strategies were devised to reflect the call-by-name and call-by-value evaluation strategies. [18] In fact, applicative order reduction was also originally introduced to model the call-by-value parameter passing technique found in Algol 60 and modern programming languages.
Even when function arguments are passed using "call by value" semantics (which is always the case in Java, and is the case by default in C#), a value of a reference type is intrinsically a reference; so if a parameter belongs to a reference type, the resulting behavior bears some resemblance to "call by reference" semantics.
Likewise, the operational semantics of simply typed lambda calculus can be fixed as for the untyped lambda calculus, using call by name, call by value, or other evaluation strategies. As for any typed language, type safety is a fundamental property of all of these evaluation strategies.
In combinatory logic for computer science, a fixed-point combinator (or fixpoint combinator), [1]: p.26 is a higher-order function (i.e. a function which takes a function as argument) that returns some fixed point (a value that is mapped to itself) of its argument function, if one exists.
In programming language theory, lazy evaluation, or call-by-need, [1] is an evaluation strategy which delays the evaluation of an expression until its value is needed (non-strict evaluation) and which avoids repeated evaluations (by the use of sharing).