— procedure: prompt-for-command-expression prompt [port [environment]]

Prompts the user for an expression that is to be executed as a command. This is the procedure called by the REP loop to read the user's expressions.

If prompt is a string, it is used verbatim as the prompt string. Otherwise, it must be a pair whose car is the symbol `standard' and whose cdr is a string; in this case the prompt string is formed by prepending to the string the current REP loop “level number” and a space. Also, a space is appended to the string, unless it already ends in a space or is an empty string.

If environment is given, it is passed as the second argument to read.

The default behavior of this procedure is to print a fresh line, a newline, and the prompt string; flush the output buffer; then read an object and return it.

Under Edwin and Emacs, before the object is read, the interaction buffer is put into a mode that allows expressions to be edited and submitted for input using specific editor commands. The first expression that is submitted is returned as the value of this procedure.

— procedure: prompt-for-command-char prompt [port]

Prompts the user for a single character that is to be executed as a command; the returned character is guaranteed to satisfy char-graphic?. If at all possible, the character is read from the user interface using a mode that reads the character as a single keystroke; in other words, it should not be necessary for the user to follow the character with a carriage return or something similar.

This is the procedure called by debug and where to read the user's commands.

If prompt is a string, it is used verbatim as the prompt string. Otherwise, it must be a pair whose car is standard and whose cdr is a string; in this case the prompt string is formed by prepending to the string the current REP loop “level number” and a space. Also, a space is appended to the string, unless it already ends in a space or is an empty string.

The default behavior of this procedure is to print a fresh line, a newline, and the prompt string; flush the output buffer; read a character in raw mode, echo that character, and return it.

Under Edwin and Emacs, instead of reading a character, the interaction buffer is put into a mode in which graphic characters submit themselves as input. After this mode change, the first such character submitted is returned as the value of this procedure.

— procedure: prompt-for-expression prompt [port [environment]]

Prompts the user for an expression.

The prompt string is formed by appending a colon and a space to prompt, unless prompt already ends in a space or is the null string.

If environment is given, it is passed as the second argument to read.

The default behavior of this procedure is to print a fresh line, a newline, and the prompt string; flush the output buffer; then read an object and return it.

Under Edwin and Emacs, the expression is read in the minibuffer.

— procedure: prompt-for-evaluated-expression prompt [environment [port]]

Prompts the user for an evaluated expression. Calls prompt-for-expression to read an expression, then evaluates the expression using environment; if environment is not given, the REP loop environment is used.

— procedure: prompt-for-confirmation prompt [port]

Prompts the user for confirmation. The result yielded by this procedure is a boolean.

The prompt string is formed by appending the string " (y or n)? " to prompt, unless prompt already ends in a space or is the null string.

The default behavior of this procedure is to print a fresh line, a newline, and the prompt string; flush the output buffer; then read a character in raw mode. If the character is #\y, #\Y, or #\space, the procedure returns #t; If the character is #\n, #\N, or #\rubout, the procedure returns #f. Otherwise the prompt is repeated.

Under Edwin or Emacs, the confirmation is read in the minibuffer.