GUILE NCURSES 2.2: A simple addstr example

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4.6.3 A simple `addstr` example

#!/usr/bin/guile
!#
(use-modules (ncurses curses)
 (srfi srfi-1))
(define stdscr (initscr))
(let* ((mesg "Just a string")
 (len (string-length mesg))
 (siz (getmaxyx stdscr))
 (row (first siz))
 (col (second siz)))
 ;; Print the message centered in the window
 (move stdscr
 (round (/ row 2))
 (round (/ (- col len) 2)))
 (addstr stdscr mesg)
 ;; Use "format" to generate a message, and then print it
 (addstr stdscr
 (format #f "This screen has ~a rows and ~a columns ~%"
 row col)
 #:y (- row 2)
 #:x 0)
 (addstr stdscr "Try resizing your window (if possible) ")
 (addstr stdscr "and then run this program again")
 (refresh stdscr)
 ;; Wait for a keypress
 (getch stdscr)
 (endwin))

The above program demonstrates how easy it is to combine addstr and move to print at a specific location on the screen. It also shows how to use the equivalent key parameters #:y and #:x. They do exactly the same thing. It also shows how (format #f …) can be used in conjunction with addstr to do formatted output.

The example introduces the new function getmaxyx. It gives the number of columns and the number of rows in a given window. getmaxyx does this by returning a list of two elements, y and x.