| Title: | Wait for a Key Press in a Terminal |
| Version: | 1.3.1 |
| Author: | Gábor Csárdi [aut, cre], Jon Griffiths [aut] |
| Maintainer: | Gábor Csárdi <csardi.gabor@gmail.com> |
| Description: | Wait for a single key press at the 'R' prompt. This works in terminals, but does not currently work in the 'Windows' 'GUI', the 'OS X' 'GUI' ('R.app'), in 'Emacs' 'ESS', in an 'Emacs' shell buffer or in 'R Studio'. In these cases 'keypress' stops with an error message. |
| License: | MIT + file LICENSE |
| URL: | https://github.com/gaborcsardi/keypress#readme |
| BugReports: | https://github.com/gaborcsardi/keypress/issues |
| RoxygenNote: | 7.1.2 |
| Encoding: | UTF-8 |
| Suggests: | covr |
| NeedsCompilation: | yes |
| Packaged: | 2023-12-11 00:55:01 UTC; gaborcsardi |
| Repository: | CRAN |
| Date/Publication: | 2023-12-11 03:40:03 UTC |
Check if the current platform/terminal supports reading single keys.
Description
Check if the current platform/terminal supports reading single keys.
Usage
has_keypress_support()
Details
Supported platforms:
Terminals in Windows and Unix.
RStudio terminal.
Not supported:
RStudio (if not in the RStudio terminal).
R.app on macOS.
Rgui on Windows.
Emacs ESS.
Others.
Value
Whether there is support for waiting for individual keypressses.
See Also
Other keypress function:
keypress()
Examples
has_keypress_support()
Read a single keypress at the terminal
Description
It currently only works at Linux/Unix and OSX terminals,
and at the Windows command line. see has_keypress_support.
Usage
keypress(block = TRUE)
Arguments
block |
Whether to wait for a key press, if there is none available now. |
Details
The following special keys are supported:
Arrow keys: 'up', 'down', 'right', 'left'.
Function keys: from 'f1' to 'f12'.
Others: 'home', 'end', 'insert', 'delete', 'pageup', 'pagedown', 'tab', 'enter', 'backspace' (same as 'delete' on OSX keyboards), 'escape'.
Control with one of the following keys: 'a', 'b', 'c', 'd', 'e', 'f', 'h', 'k', 'l', 'n', 'p', 't', 'u', 'w'.
Value
The key pressed, a character scalar. For non-blocking reads NA is returned if no keys are available.
See Also
Other keypress function:
has_keypress_support()
Examples
x <- keypress()
cat("You pressed key", x, "\n")
Call a function with echo suppressed
Description
For Linux/Unix and OSX terminals, suppress key echoes from the terminal.
Usage
without_echo(expr)
Arguments
expr |
Expression to evaluate without terminal echo. |
Details
You will need to set echo to FALSE if you want the R script to handle all of the keypress-related behaviour, without any keys being echoed in the terminal by the operating system, when using non-blocking keypress. This is not necessary when running in a Windows command prompt, and will be safely ignored.