;;; Some scsh utilities to mung the tty.
;;; Designed and implemented by David Fisher and Olin Shivers.
;;; Copyright (C) 1998 by the Scheme Underground.

;;; (modify-tty proc [tty-fd/port/fname])
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;;; Get the tty's current tty-info record. Apply PROC to the record;
;;; set the tty's mode to the result tty-info record returned by PROC.
;;; Return the original, unmodified tty-info record.

;;; RAW RAW-INITIALIZE ECHO-ON ECHO-OFF CANONICAL
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;;; These are tty-info -> tty-info functions. They can be used as the PROC
;;; parameter to MODIFY-TTY.

(define (modify-tty proc . maybe-tty)
  (let* ((tty (:optional maybe-tty (current-input-port)))
	 (info0 (tty-info tty)))
    (set-tty-info/now tty (proc (copy-tty-info info0)))
    info0))

;;; Make a proc that frobs the :local-flags field of a tty-info record.
(define (local-flags-modifier modifier)
  (lambda (ti)
    (modify-tty-info:local-flags ti modifier)
    ti))

(define echo-off
  (let ((no-echo (bitwise-not ttyl/echo)))
    (local-flags-modifier (lambda (lf) (bitwise-and lf no-echo)))))

(define echo-on
  (local-flags-modifier (lambda (lf) (bitwise-ior lf ttyl/echo))))

(define raw
  (let ((no-canon (bitwise-not ttyl/canonical)))
    (local-flags-modifier (lambda (lf) (bitwise-and lf no-canon)))))

(define (raw-initialize tty-info)
  ;; min and time can't be set until the terminal is in raw mode.  Really.
  (set-tty-info:min tty-info 0)
  (set-tty-info:time tty-info 0)
  tty-info)

(define canonical
  (local-flags-modifier (lambda (lf) (bitwise-ior lf ttyl/canonical))))