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Higher Order Message
A higher order message (HOM) in a computer programming language is a form of higher-order programming that allows messages that have other messages as arguments. The concept was introduced at MacHack 2003 by Marcel Weiher and presented in a more complete form in 2005 by Marcel Weiher and Stéphane Ducasse. Loops can be written without naming the collections looped over, higher order messages can be viewed as a form of point-free or tacit programming. Examples In ordinary Smalltalk code, without using HOM, obtaining a collection of the employees that have a salary of 1000 would be achieved with the following code: salaried := employees select: each hasSalary: 1000 However, using HOM, it can be expressed as follows: salaried := employees select hasSalary: 1000. Here, select is a higher order message, and hasSalary: is understood to be called on the select message itself, rather than on its result. The Smalltalk language was not modified to implement this feature. Instead, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Programming Language
A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language. The description of a programming language is usually split into the two components of syntax (form) and semantics (meaning), which are usually defined by a formal language. Some languages are defined by a specification document (for example, the C programming language is specified by an ISO Standard) while other languages (such as Perl) have a dominant implementation that is treated as a reference. Some languages have both, with the basic language defined by a standard and extensions taken from the dominant implementation being common. Programming language theory is the subfield of computer science that studies the design, implementation, analysis, characterization, and classification of programming languages. Definitions There are many considerations when defini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
