1 Introduction

1.1 About the Loop Facility

A loop is a series of expressions that are executed one or more times, a process known as iteration. The Loop Facility is an extensible iteration mechanism that provides you with a variety of ways to iterate and to accumulate values in a loop. It differs from the Common Lisploop macro in that it allows you to use defined loop keywords to control the parameters of the iteration.

Loop keywords are not true Common Lisp keywords; they are symbols that are recognized by the Loop Facility and that provide such capabilities as controlling the direction of iteration, accumulating values inside the body of a loop, and evaluating expressions that precede or follow the loop body. If you do not use any loop keywords, the Loop Facility is identical to the Common Lisploop macro; that is, it executes the loop body repeatedly. Thus, the Loop Facility is an upward-compatible extension to the Common Lisploop macro.

1.1.1 - How the Loop Facility works
1.1.2 - Differences between LOOP and DO

The Loop Facility - 9 SEP 1996

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