Introduced in the 1995 ANSI M[UMPS] language standard.
The value of $KEY is the string that terminated the most recent input.
After a command like READ X#20, the value of
$KEY is most likely to be equal to the empty string.
After a command like READ X, the value of
$KEY will usually be equal to $CHAR(13) (the enter-
key). However, when input was terminated by typing a function
key, the value of $KEY will be equal to the string of
characters that is transmitted by that function key. The most
common function keys on the VT-100 and compatible terminals
are:
| Key | Code sequence |
|---|---|
| Up arrow | $CHAR(27,91,65) |
| Down arrow | $CHAR(27,91,66) |
| Right arrow | $CHAR(27,81,67) |
| Left arrow | $CHAR(27,91,68) |
| PF1 | $CHAR(27,80) |
| PF2 | $CHAR(27,81) |
| PF3 | $CHAR(27,82) |
| PF4 | $CHAR(27,83) |
In addition, the VT-200 terminals (and the more modern versions of that family of terminals) also offer:
| Key | Code sequence |
|---|---|
| Find | $CHAR(27,91)_"1~" |
| Insert | $CHAR(27,91)_"2~" |
| Remove | $CHAR(27,91)_"3~" |
| Select | $CHAR(27,91)_"4~" |
| Previous page | $CHAR(27,91)_"5~" |
| Next page | $CHAR(27,91)_"6~" |
| F7 | $CHAR(27,91)_"18~" |
| F8 | $CHAR(27,91)_"19~" |
| F9 | $CHAR(27,91)_"20~" |
| F10 | $CHAR(27,91)_"21~" |
| F11 | $CHAR(27,91)_"23~" |
| F12 | $CHAR(27,91)_"24~" |
| F13 | $CHAR(27,91)_"25~" |
| F14 | $CHAR(27,91)_"26~" |
| Help | $CHAR(27,91)_"28~" |
| Do | $CHAR(27,91)_"29~" |
| F17 | $CHAR(27,91)_"31~" |
| F18 | $CHAR(27,91)_"32~" |
| F19 | $CHAR(27,91)_"33~" |
| F20 | $CHAR(27,91)_"34~" |
The initial value of $KEY is implementation-dependent. However, if the initial value of $IO is the empty string, then the initial value of $KEY is also the empty string.
This document is © Ed de Moel, 1995-2005.
It is part of a book by Ed de Moel that is published under the
title "M[UMPS] by Example" (ISBN 0-918118-42-5).
Printed copies of the book are no longer available.
This document describes the various special variables that are defined in the M[UMPS] language standard (ANSI X11.1, ISO 11756).
The information in this document is NOT authoritative
and subject to be modified at any moment.
Please consult the appropriate (draft) language standard for an
authoritative definition.
In this document, information is included that will
appear in
future standards.
The MDC cannot guarantee that these 'next'
standards will indeed appear.