pop-up-windows « 1

Controls window pop-ups. If non-zero, Emacs will try to use a window other than the current window when it spontaneously generates a buffer that it wants you to see, or when you visit a file. If set to zero, the current window is always used.

prefix-argument

Every function invocation is always prefixed by a numeric argument, either explicitly with prefix-argument or implicitly with provide-prefix-argument. The value of the variable prefix-argument is the argument prefixed to the invocation of the current MLisp function.

prefix-argument-provided

If non-zero, a prefix argument has been provided for the current function. The value of prefix-argument-provided can be obtained from the prefix-argument variable.

prefix-string «

Contains the string that is inserted after an automatic newline has been generated in response to moving the cursor past the right margin. This is generally used by the language-dependent commenting features.

previous-directory «

This variable is used by Barry's Emacs as part of support its bemacs command line interface to the bemacs_server process.

Each time Barry's Emacs starts to process a new command line the current directory is recorded in the previous-directory variable.

Once the command line process finishes Emacs automatically sets the current directory to the value held in previous-directory.

The command line processing MLisp code can cause Emacs's current directory to change by setting previous-directory to a suitable directory.

The MLisp Programmers Guide has furthur information about Command Lines. Including how to customise command line handling.

process-key-hook «

This buffer-specific variable holds the name of a function to call after each keymap command. last-keys-struck holds the string of keys that invoked the last command.