The purpose of a programming system is to make a computer easy to use. To do this, it furnishes languages and various facilities that are in fact programs invoked and controlled by language features. But these facilities are bought at a price: the external description of a programming system is ten to twenty times as large as the external description of the computer system itself. The user finds it far easier to specify any particular function, but there are far more to choose from, and far more options and formats to remember. Ease of use is enhanced only if the time gained in functional specification exceeds the time lost in learning, remembering, and searching manuals. With modern programming systems this gain does exceed the cost, but in recent years the ratio of fain to cost seems to have fallen as more and more complex（ ） have been added.
Because ease of use is the purpose, this radio of function to conceptual complexity is the ultimate test of system design. Neither function alone nor simplicity alone（ ）a good design.
This point is widely misunderstood. Function, and not simplicity, has always been the measure of excellence for its designers. As soon as ease of use is held up as the criterion, each of these is seen to be（ ）, reaching for only half of the true goal.
For a given level of function, however, that system is best in which one can specify things with the most simplicity and straightforwardness. （ ）is not enough. Mooer’s TRAC language and Algol 68 achieve simplicity as measured by the number of distinct elementary concepts.
They are not, however, straightforward. The expression of the things one wants to do often requires involuted (复杂的）and unexpected combinations of the basic facilities. It is not enough to learn the elements and rules of combination; one must also learn the idiomatic usage, a whole lore of how the elements are combined in practice. Simplicity and straightforwardness proceed from conceptual（ ）. Every part must reflect the same philosophies and the same balancing of desiderata. Every part must use the same techniques in syntax and the analogous notions in semantics. Ease of use, then, dictates unity of design, conceptual integrity.
编程系统的目的是为了使计算机易于使用。为此，它提供语言和各种设施，实际上是 由语言特征调用和控制的程序。但是这些设施是以一种代价购买的：编程系统的外部 描述是计算机系统本身的外部描述的十到二十倍。用户发现更容易指定任何特定的功 能，但还有更多的选择，还有更多的选项和格式要记住。
只有在功能说明书中获得的时间超过了学习，记忆和搜索手册所花费的时间，才能增 强易用性。使用现代编程系统，这种收益确实超出了成本，但近年来，随着越来越多 的复杂的____增加，迷失与成本的比率似乎已经下降。
因为易用性是目的，这种无线电功能的概念复杂性是系统设计的最终测试。既不功能单独也不单纯简单____一个好的设计。
这一点被广泛误解。功能和不简单，是设计师追求卓越的衡量标准。 一旦以易用性 为标准，每个都被认为是_____，达到真正目标的一半。
然而，对于给定的功能级别，该系统最好是以最简单和直观的方式指定事物。 ____ 是不足够的。 Mooer 的 TRAC 语言和 Algol 68 通过不同的基本概念的数量来实现简单性。
然而，他们并不直接。事情的表达往往需要复杂的和基础设施的组合。学习组合的要素和规则是不够的，还必须学习惯用语，一个全面的理解元素在实践中相结合。简单直接进行来自于概念上的____。 每一部分都必须反映出同样的哲学和平衡的欲望。 每个部分必须在语法和语义中类似的概念中使用相同的技术。易于使用，决定了设计的一致性，概念的完整性。