Expressions
In most languages, statements contrast with expressions in that statements do not return results and are executed solely for their side effects, while expressions always return a result and often do not have side effects at all. Among imperative programming languages, Algol 68 is one of the few in which a statement can return a result. In languages which mix imperative and functional styles, such as the Lisp family, the distinction between expressions and statements is not made: even expressions executed in sequential contexts solely for their side effects and whose return values are not used are considered 'expressions'. In purely functional programming, there are no statements; everything is an expression.
Read more about this topic: Statement (computer Science)
Famous quotes containing the word expressions:
“Many expressions in the New Testament come naturally to the lips of all Protestants, and it furnishes the most pregnant and practical texts. There is no harmless dreaming, no wise speculation in it, but everywhere a substratum of good sense. It never reflects, but it repents. There is no poetry in it, we may say, nothing regarded in the light of beauty merely, but moral truth is its object. All mortals are convicted by its conscience.”
—Henry David Thoreau (1817–1862)
“Let it be signified to me through any channel ... that the possession of the Floridas would be desirable to the United States, and in sixty days it will be accomplished.
...penned in the language of truth, and divested of those expressions of servility which would persuade his majesty that we are asking favors and not rights.”
—Thomas Jefferson (1743–1826)
“Compare the history of the novel to that of rock ‘n’ roll. Both started out a minority taste, became a mass taste, and then splintered into several subgenres. Both have been the typical cultural expressions of classes and epochs. Both started out aggressively fighting for their share of attention, novels attacking the drama, the tract, and the poem, rock attacking jazz and pop and rolling over classical music.”
—W. T. Lhamon, U.S. educator, critic. “Material Differences,” Deliberate Speed: The Origins of a Cultural Style in the American 1950s, Smithsonian (1990)