英和和英

出典:『Wikipedia』 (2011/05/30 12:50 UTC 版)

英語による解説

引用

In computer programming, a guard is a boolean expression that must evaluate to true if the program execution is to continue in the branch in question. The term is used at least in Haskell, Clean, Erlang, occam, Promela and OCaml programming languages. In Mathematica, guards are called constraints. Guards are the fundamental concept in Guarded Command Language, a language in formal methods. Guards can be used to augment pattern matching with the possibility to skip a pattern even if the structure matches. Boolean expressions in conditional statements usually also fit this definition of a guard although they are called conditions.