Path: utzoo!attcan!uunet!snorkelwacker!ira.uka.de!smurf!gopnbg!mcshh!shin
From: shin@mcshh.hanse.de (Thomas Braun)
Newsgroups: comp.lang.smalltalk
Subject: POSTING: A Watch For Smalltalk/V286
Keywords: Interrupt, Multi Processing
Message-ID: <8125@mcshh.hanse.de>
Date: 29 Sep 90 05:27:27 GMT
Distribution: comp
Lines: 97

"
 Smalltalk/V286 Source:  'watch.sml'
 
 ----------------------------------------------------------
 This file installs a visible watch on the DisplayScreen
 by defining and redefining methods for the classes
 String, Process and ScreenDispatcher. 
 
 When loaded, you will find a new option in the ScreenMenu
 of the ScreenDispatcher to switch the watch on and off. 
 I wrote this little piece while studying multi processing
 capabilities of Smalltalk/V. It shows how to bring up a 
 background process initiated by interrupt and signaling 
 the KeyboardSemaphore                                    
 
 good vibes... Thomas Braun
 ----------------------------------------------------------
 
 To load this file evaluate the following message
 
 (File pathName: 'watch.sml')
      fileIn;
      close.
 
 where the file should be in the current directory.
 
"!
 
Smalltalk at: #Watch put: (0=1)!  
Transcript cr; show: 'Filing in the visible watch...'!
 
!String methods !
 
displayAt: aPoint font: aFont
             foreColor: fore
             backColor: back
        "Output the receiver onto the display screen."
    CharacterScanner new
        initialize: Display boundingBox font: aFont;
        setForeColor: fore backColor: back;
        display: self at: aPoint! !
 
!Process class methods !
 
timerInterrupt
        "Implement the timer interrupt."
    PendingEvents add: (Message new
        selector: #clockEvent:;
        arguments: (Array with: 1)).
    (Time now) printString
        displayAt: 656 @ 0 
        font: (Font eightLine)
        foreColor: Form white
        backColor: Form gray.
    KeyboardSemaphore signal.
    self enableInterrupts: true! !
 
 
!ScreenDispatcher class methods !
 
initialize
        "Private - Initialize the system menu."
    | aString |
    BackupWindow
        ifTrue: [aString := 'dos shell\speed/space\exit Smalltalk\browse disk\open workspace\browse classes\redraw screen\save image\switch clock\run demo' withCrs]
        ifFalse:[aString := 'dos shell\space/speed\exit Smalltalk\browse disk\open workspace\browse classes\redraw screen\save image\switch clock\run demo' withCrs].
    ScreenMenu := Menu
        labels: aString
        lines: #(3 7)
        selectors: #(dosMenu speedSpace exit openDiskBrowser openWorkspace openClassBrowser redraw save switchWatch runDemo)! !
 
 
!ScreenDispatcher methods !
 
switchWatch 
        "switch the watch on and off"
    Watch 
       ifTrue: [ Time clockTicksOff.
                 Watch := (0=1).
                 '        '
                    displayAt: 650 @ 2
                    font: (Font fourteenLine)
                    foreColor: Form white
                    backColor: Form gray.]
       ifFalse:[ Time clockTickPeriod:20.
                 Watch := (0=0)]
    ! !
 
ScreenDispatcher initialize.!
Transcript show: 'Done.' withCrs.
!
-------------------------cut here--------------------------
Thomas Braun		      uucp: ..mcshh!shin
Vedd. Brueckenstr.81	     phone: 49 040 784258
2000 Hamburg 26
GERMANY
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