Nautical bell

Nautical bell is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

The task is to write a small program that emulates a nautical bell producing a ringing bell pattern at certain times throughout the day.

The bell timing should be in accordance with Greenwich Mean Time, unless locale dictates otherwise.

It is permissible for the program to [Run as a daemon|daemonize], or to slave off a scheduler, and it is permissible to use alternative notification methods (such as producing a written notice "Two Bells Gone"), if these are more usual for the system type.

REXX

The local time is used instead of Grenwich mean time.

If any arguments are specified, this causes the REXX program to use that text to prefix the time shown.
Also, the number of bells sounded are shown (if any arguments are specified).
In all cases, the PC speaker is used to sound the bells (albeit a poorly sounded bell).

This REXX program makes use of   DELAY   BIF which delays (sleeps) for a specified amount of seconds.
Some REXXes doen't have a   DELAY   BIF, so one is included here ──► DELAY.REX.

This REXX program makes use of   SOUND   BIF which produces sounds via the PC speaker.
Some REXXes doen't have a   SOUND   BIF, so one is included here ──► SOUND.REX. <lang rexx>/*REXX pgm sounds "bells" (using PC speaker) when running (perpetually).*/ echo= arg()\==0 /*echo time & bells if any args. */ signal on halt /*allow a clean way to stop prog.*/ t.1 = '00:30 01:00 01:30 02:00 02:30 03:00 03:30 04:00' t.2 = '04:30 05:00 05:30 06:00 06:30 07:00 07:30 08:00' t.3 = '08:30 09:00 09:30 10:00 10:30 11:00 11:30 12:00'

      do forever;  t=time();  ss=right(t,2);  mn=right(t,2)    /*times.*/
      ct=time('C')                              /*[↓] add leading zero.*/
      hhmmc=left( right( ct, 7, 0),  5)         /*HH:MM (leading zero).*/
      if echo  then say center(arg(1) ct, 79)   /*echo arg1 with time ?*/
      if ss\==00 & mn\==00 & mn\==30 then       /*wait for next min ?  */
        do;  call delay 60-ss;  iterate;  end   /*delay fraction of min*/

                                                /*[↓]  # bells to peel.*/
        do j=1 for 3  until $\==0;  $=wordpos(hhmmc,t.j);  end /*j*/

      if $\==0 & echo  then say center($ "bells", 79)    /*echo bells? */

        do k=1 for $; call sound 650,1; call delay 1+(k//2==0); end /*k*/
                                                /*[↑]   peel and pause.*/
      call delay 60                             /*ensure don't re-peel.*/
      end   /*forever*/

halt: /*stick a fork in it, we're done.*/ </lang> output when using the input of: the time is:

                             the time is:   1:48pm
                             the time is:   1:49pm
                             the time is:   1:50pm
                             the time is:   1:51pm
                             the time is:   1:52pm
                             the time is:   1:53pm
                             the time is:   1:54pm
                             the time is:   1:55pm
                             the time is:   1:56pm
                             the time is:   1:57pm
                             the time is:   1:58pm
                             the time is:   1:59pm
                             the time is:   2:00pm
                                    4 bells
                             the time is:   2:01pm
                             the time is:   2:02pm
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