31.9. The Prompt

CLISP prompt consists of 3 mandatory parts: start, body, and finish; and 2 optional parts: break, which appears only in the debugger (after BREAK or ERROR), and step, which appears only in the STEPer. Each part is controlled by a custom variable, which can be either a STRING or a FUNCTION of no arguments returning a STRING (if it is something else - or if the return value was not a STRING - it is printed with PRINC). In the order of invocation:

Defaults to an empty string.
Used only during STEPping. Defaults to Step n , where n is the stepping level as returned by EXT:STEP-LEVEL.
Used only inside break loop (during debugging). Defaults to Break n , where n is the break level as returned by EXT:BREAK-LEVEL.
Defaults to package[n] where package is the shortest (nick)name (as returned by EXT:PACKAGE-SHORTEST-NAME) of the current package *PACKAGE* if it is not the same as it was in the beginning (determined by EXT:PROMPT-NEW-PACKAGE) or if it does not contain symbol T, (it is assumed that in the latter case you would want to keep in mind that your current package is something weird); and n is the index of the current prompt, kept in EXT:*COMMAND-INDEX*.
Defaults to .

To facilitate your own custom prompt creation, the following functions and variables are available:

This FUNCTION returns current BREAK/ERROR level.
This FUNCTION returns current STEP level.
This FUNCTION returns *PACKAGE* or NIL if the current package is the same as it was initially.
This FUNCTION takes one argument, a PACKAGE, and returns its shortest name or nickname.
contains the current prompt number; it is your responsibility to increment it (this variable is bound to 0 before saving the memory image).

These notes document CLISP version 2.49Last modified: 2010-07-07