syscalls: Add 'terminal-rows'.

* guix/build/syscalls.scm (terminal-dimension): New procedure.
(terminal-columns): Rewrite in terms of 'terminal-dimension'.
(terminal-rows): New procedure.
* tests/syscalls.scm ("terminal-rows"): New test.
This commit is contained in:
Ludovic Courtès 2019-06-25 23:05:00 +02:00
parent 8874faaaac
commit 4593f5a654
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2 changed files with 29 additions and 13 deletions

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@ -146,6 +146,7 @@
window-size-y-pixels
terminal-window-size
terminal-columns
terminal-rows
utmpx?
utmpx-login-type
@ -1871,23 +1872,17 @@ corresponds to the TIOCGWINSZ ioctl."
(list (strerror err))
(list err)))))
(define* (terminal-columns #:optional (port (current-output-port)))
"Return the best approximation of the number of columns of the terminal at
PORT, trying to guess a reasonable value if all else fails. The result is
always a positive integer."
(define (fall-back)
(match (and=> (getenv "COLUMNS") string->number)
(#f 80)
((? number? columns)
(if (> columns 0) columns 80))))
(define (terminal-dimension window-dimension port fall-back)
"Return the terminal dimension defined by WINDOW-DIMENSION, one of
'window-size-columns' or 'window-size-rows' for PORT. If PORT does not
correspond to a terminal, return the value returned by FALL-BACK."
(catch 'system-error
(lambda ()
(if (file-port? port)
(match (window-size-columns (terminal-window-size port))
(match (window-dimension (terminal-window-size port))
;; Things like Emacs shell-mode return 0, which is unreasonable.
(0 (fall-back))
((? number? columns) columns))
((? number? n) n))
(fall-back)))
(lambda args
(let ((errno (system-error-errno args)))
@ -1900,6 +1895,24 @@ always a positive integer."
(fall-back)
(apply throw args))))))
(define* (terminal-columns #:optional (port (current-output-port)))
"Return the best approximation of the number of columns of the terminal at
PORT, trying to guess a reasonable value if all else fails. The result is
always a positive integer."
(define (fall-back)
(match (and=> (getenv "COLUMNS") string->number)
(#f 80)
((? number? columns)
(if (> columns 0) columns 80))))
(terminal-dimension window-size-columns port fall-back))
(define* (terminal-rows #:optional (port (current-output-port)))
"Return the best approximation of the number of rows of the terminal at
PORT, trying to guess a reasonable value if all else fails. The result is
always a positive integer."
(terminal-dimension window-size-rows port (const 25)))
;;;
;;; utmpx.

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@ -1,5 +1,5 @@
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2014, 2015, 2016, 2017, 2018 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2014, 2015, 2016, 2017, 2018, 2019 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2015 David Thompson <davet@gnu.org>
;;;
;;; This file is part of GNU Guix.
@ -538,6 +538,9 @@
(> (terminal-columns (open-input-string "Join us now, share the software!"))
0))
(test-assert "terminal-rows"
(> (terminal-rows) 0))
(test-assert "utmpx-entries"
(match (utmpx-entries)
(((? utmpx? entries) ...)