ToC DocOverview CGDoc RelNotes Index PermutedIndex
Allegro CL
Home Previous Up Next Table of Contents Index
  ANSI Common Lisp   25 Environment   25.2 Dictionary of Environment

25.2.9 step Macro

step form    {result}*

Arguments and Values:
form - a form; evaluated as described below.

results - the values returned by the form.

step implements a debugging paradigm wherein the programmer is allowed to step through the evaluation of a form. The specific nature of the interaction, including which I/O streams are used and whether the stepping has lexical or dynamic scope, is implementation-defined.

step evaluates form in the current environment. A call to step can be compiled, but it is acceptable for an implementation to interactively step through only those parts of the computation that are interpreted.

It is technically permissible for a conforming implementation to take no action at all other than normal execution of the form. In such a situation, (step form) is equivalent to, for example, (let () form). In implementations where this is the case, the associated documentation should mention that fact.


See Also:

Implementations are encouraged to respond to the typing of ? or the pressing of a "help key" by providing help including a list of commands.

Allegro CL Implementation Details:
See The original stepper and the subsequent sections in debugging.htm for information on the Allegro CL implementation of the step macro. See also the top-level command :step. Note the links are to the documentation for the current Allegro CL version. Replace /current/ in the URL with the Allegro CL version number to see similar documentation in earlier releases.

Home Previous Up Next Table of Contents Index
© Franz Inc. All Rights Reserved - File last updated 2022-07-25