TweetFollow Us on Twitter

FKeys, Events
Volume Number:3
Issue Number:9
Column Tag:Forth Forum

FKeys & Events

By Jörg Langowski, MacTutor Editorial Board, Grenoble, France

FKEYs and Events

The example we’ll deal with this time has some history. On a national bulletin board here in France, Calvacom, which has a large section of its activity devoted to the Mac, a proposal was made to write an FKEY that would paste one of a number of character strings into the application currently under use. Thus one would have an easy way to enter ‘boilerplate’ phrases or often used commands into text processors, terminal emulators etc.

I thought this would make a nice example for the Forth column, especially since we hadn’t had an FKEY dealt with yet. In the way of writing this, I discovered several things. First, the simple strategy that comes to mind - taking a string that was saved away somewhere and posting key down events for one character after the other - works only in certain cases, so one has to go a more complicated way (as you’ll see soon). Second, somebody had of course in the meantime written the FKEY under question - in some other language. Nevertheless, still a good Forth example.

Implementing an FKEY

Everyone of you has probably already used one or the other function key, that is, command-shift-number combination. Some might even have written one, its implementation being rather simple. The FKEY resource is a simple subroutine with its entry point at the beginning of its code. It is called from the routine that handles the keyboard. If that routine detects a command-shift-number combination, it will look for the FKEY resource corresponding to the number, and if such a resource is present, load and execute it.

No parameters are passed to the FKEY routine on the stack; we’ll simply set up a local Forth stack on entry to the routine, using LINK, save all registers away, then call the main body of the FKEY, and finally restore the registers and UNLINK A6. This is the standard glue routine for writing kernel-independent Mach2 code which you might already be familiar with. See listing 1.

[One remark with regard to the listing here. This program has been written in Mach2.12 which has a different Toolbox call mechanism than earlier versions. In particular, it expects D4 to point to a common stack low in memory which can be used for all toolbox calls. This stack, and D4, are set up in the Mach2 system. Therefore, to write kernel-independent code, one has to use the old CALL mechanism again. This word is available under a new name: (CALL). If you have an older Mach2 version, simply replace all occurrences of (CALL) with CALL, or redefine the word].

The main body of the FKEY will first look whether it has been called from a bona fide application or whether the topmost window is a dialog or desk accessory. In the latter two cases, the FKEY will do nothing but beep and return. Since the FKEY itself might display a dialog (for editing the text strings), it should not be allowed to redisplay its own dialog when it is already active. Checking whether any dialog is already in place is one way of achieving this; you might think up some more sophisticated ways and change the program accordingly.

If the routine has been called from within a good environment, it will wait for the next key pressed. If the key is a number key, the appropriate message will be posted (see later how this is done). If it is the ‘e’ key, a dialog will be displayed for editing the text strings. In all other cases the routine will simply beep and return.

Posting Events

The first problem that we encounter here is how to post key down events that correspond to the text string into the event queue. Very simple, you’ll say, do the following:

: post.char ( char -- ) 3 swap call post.event drop ;
 : post.string ( string -- )
 count 0 DO dup i + c@ post.char LOOP drop ;

where 3 is the event code for a key down event, and the event message simply contains the character code in the low byte, and no key code (=0). Leaving out the actual key code has so far caused no problem in any case that I tested.

Well, the simple example works. In a way. If the string that is posted is longer than 15 characters, Mach2 will simply beep because it cannot accept more keydown events before switching tasks. This doesn’t have anything to do with the actual length of the event queue or the maximum number of allowed events. It is the application that can’t deal with so many ‘keystrokes’ coming in rapid succession. In addition, of course, if we don’t check the event queue before posting an event, we take the risk of losing it if the maximum number of allowed events (20 by default) has been reached.

This last number can be changed by editing the boot blocks. However, one can think of a more elegant solution that makes the whole process completely independent of the maximum length of the event queue. We allow the posting of a character only if the GetNextEvent routine fetches a null event. In that case we can be sure that not too much activity is going on and the key down event will be handled correctly.

But how do we handle this process? We cannot do some sort of waiting loop within the FKEY, since GetNextEvent will only be called by the application after we have returned. Therefore the FKEY must install a short background routine that monitors the activity of GetNextEvent and posts key down events from the string to be transmitted each time a null event is received. Here the JGNEFilter system global, already used for several examples in MacTutor (V1#9, Bob Denny, and V2#6, JL), comes in very handy. To post a message into the event queue, the post.string word as defined in the listing saves the string and its length away into a defined place and then changes the JGNEFilter vector to point to a custom routine that will post the keystrokes.

The custom routine, GNE.glue, calls GNEIntfc through our standard glue code, which you really know by now. GNEIntfc looks at A1 (which points to the event record), and if a null event is about to be transmitted, it will take the next character from the saved message string and post a key down event under the following conditions:

1. A certain delay has expired since the last character was posted (2 ticks in my example) and

2. The number of pending events is less than a predefined number (here 10).

When the end of the string has been reached, the filter routine resets the JGNEFilter vector to its old value.

Using the method just described, one can transmit strings of arbitrary length to applications. Which is what we wanted.

Editing the text strings

If an ‘e’ is pressed after the FKEY, we’ll display the editing dialog. The Rmaker source for this dialog (ID=2000 for DLOG and DITL, you may want to change this) is in listing 2. It simply consists of 10 editable text items, one OK button and some static text.

The associated Forth word, edit.messages, does a number of things. It first tries to open a resource file named ‘FKEY.messages’ and creates a new one if it doesn’t succeed. By standard, this will be kept in the system folder; leave it there. You can prepare any number of files containing standard messages by renaming them.

The routine then gets the dialog with ID 2000 (it is a shame that FKEYs cannot ‘own’ resources like DRVRs etc. can). If the dialog can’t be found, it beeps and returns; otherwise, it displays the strings from the FKEY.messages file in the boxes for the editable text items. They are 10 individual string-format resources type ‘bplt” with ID=3 to 12 (corresponding to the dialog items 3 to 12). If the resources cannot be found (i.e. the file has just been created and is empty), they are created and initialized with whatever was in the EditText items of the dialog box. In my case, I used the texts ‘Message x’, but you might just leave the strings empty. If the bplt resources are there, they replace the EditText items.

A ModalDialog is then called, allowing the strings to be edited. The only enabled item is the OK button, which returns to the Forth routine. Then, the changed text strings are written back to the bplt resources in the FKEY.messages file, the resource file updated and the dialog disposed of.

Finally, post.message is the routine that is called when a number key is pushed after the FKEY. It gets the bplt resource corresponding to that number and calls post.string (described above) to transmit the string via the GetNextEvent filter routine.

make.fkey creates a file ‘fkey.text’ that contains the FKEY resource and has the correct type and creator to be opened from the FKEY installer (from Quick and Dirty Utilities, Dreams of the Phoenix, Inc., P.O.Box 10273, Jacksonville FL 32247, (904) 396-6952). This file is then packed together with the dialog resources into one file. The FKEY may be installed with the installer; the DLOG 2000 and DITL 2000 must be copied with ResEdit.

Some last notes

As you’ve seen, yet another Mach2 version has been released, v2.12, making v2.11 obsolete only two weeks after I received it. No BIG modifications, only minor ones.

I received some comments from a reader, James Merkel, who mentioned that it would be a good idea for Palo Alto Shipping to release the source for the multitasking kernel as well, now that we have the source of the I/O task. The second comment was to release bug fixes in MacTutor as well as on GEnie, for those not having access to the GEnie Roundtable (including myself). Very good suggestion. PAS, do you listen?

Last, the bulletin board that I mentioned, Calvacom, is now accessible via Tymnet from the US. If you’d like to see what’s going on over here or want to leave me some mail, connect yourself to a Tymnet line and type ‘CalvaCom’ at the login prompt, then ‘nouveau’ when it prompts you for your access code. You can subscribe with your credit card, as usual. Speaking some French helps, of course, but most anybody on the board will understand English. Connect charges (overseas rates included) are of the order of $25 per hour. I’d like to see your feedback in my mailbox!

{1}
Listing 1: Mach2 FKEY for text glossary
( *** Function Key example. JL June 1987 *** )
ONLY FORTH ALSO ASSEMBLER ALSO MAC

4ascii QD15 CONSTANT “qd15
4ascii bplt CONSTANT “bplt
4ascii DITL CONSTANT “ditl
4ascii DLOG CONSTANT “dlog

2 CONSTANT post.delay
 ( 2 ticks wait between posting of characters )
10 CONSTANT max.event  
 ( max # of pending events allowed during posting )
$14a CONSTANT EvQHdr
$29A CONSTANT JGNEFilter
2 CONSTANT QHead
6 CONSTANT QTail
BINARY 0000000000001000 CONSTANT KeyEvent
DECIMAL
 ( header code filled at end of definitions )
header start
 JMP start  ( to be filled later )
header temprect 8 allot
header itemrect 8 allot
header myEventRec 16 allot

: beep 5 (call) sysbeep ;

CODE cmove ( redefine since this is part of Kernel )
 MOVE.L (A6)+,D0
 MOVE.L (A6)+,A1
 MOVE.L (A6)+,A0
 TST.L  D0
 BLE.S  @2
@1 MOVE.B (A0)+,(A1)+
 SUBQ.L #1,D0
 BNE.S  @1
@2 RTS
END-CODE

: / w/ ;

: getFkeyDlg 
 2000 0 -1 (call) GetNewDialog 
;

: #events EvQHdr QTail + @ EvQHdr QHead + @ - 22 / ;

: post.char ( char -- ) 3 swap (call) postEvent drop
 ;

header SavedJGNEFilter 4 allot
header SavedString 256 allot
header bytesToTransfer 4 allot
header lastpost 4 allot

: GNEIntfc { | btt -- }
    getA1 w@ 0= IF
 [‘] bytesToTransfer @ -> btt
 btt IF  (call) tickcount [‘] lastpost @ - post.delay > 
 #events max.events < AND 
 IF
 [‘] SavedString dup c@ btt - 1+
 + c@ post.char
 btt 1- [‘] bytesToTransfer !
 (call) tickcount [‘] lastpost !
 THEN
 ELSE
 [‘] savedJGNEFilter @ JGNEFilter !
 THEN
    THEN
;    
CODE GNE.glue
 LINK A6,#-256 ( 256 bytes of local Forth stack )
 MOVEM.L A0-A5/D0-D7,-(A7)( save registers )
 ( no need for loop return stack )
 ( no parameters are passed )
 JSR GNEintfc  ( call Forth routine )
 MOVEM.L (A7)+,A0-A5/D0-D7( restore registers )
 UNLK A6
 LEA  SavedJGNEFilter,A0
 MOVE.L (A0),A0  ( return address )
 JMP  (A0)
END-CODE

: post.string { string | length -- }
 string c@ -> length
 string [‘] SavedString length 1+ cmove
 length [‘] bytesToTransfer !
 (call) tickcount [‘] lastpost !
 JGNEFilter @ [‘] SavedJGNEFilter !
 [‘] GNE.glue JGNEFilter !
;

: post.message { msg# | dh dPtr tPtr -- }
 “ FKEY.messages” (call) OpenResFile (call) UseResFile
 “bplt msg# 3 + (call) getResource -> dh
 dh IF dh @ post.string
 ELSE beep THEN
;

: edit.messages 
 { | dPtr itemType item box box1 itemHit thandle refnum -- }
 “ FKEY.messages” dup (call) OpenResFile
 (call) ResError 
 IF drop dup (call) CreateResFile
 (call) OpenResFile dup -> refNum 
 (call) UseResFile 
 ELSE dup -> refNum 
 (call) UseResFile drop 
 THEN 
 getFkeyDlg -> dPtr
 dPtr IF
 13 3 DO 
 dPtr i ^ itemType ^ item ^ box
 (call) GetDItem
 item (call) HLock drop
 “bplt i (call) GetResource -> thandle
 thandle IF 
 thandle (call) HLock drop
 item thandle @ (call) SetIText 
 thandle (call) HUnlock drop 
 ELSE
 256 (call) NewHandle drop
 “bplt i “ Message” (call) AddResource
 THEN
 item (call) HUnlock drop
 LOOP ( all messages have been initialized )

 0 ^ itemHit (call) ModalDialog

 13 3 DO 
 dPtr i ^ itemType ^ item ^ box
 (call) GetDItem
 item (call) HLock drop
 “bplt i (call) GetResource -> thandle
 thandle IF 
 thandle (call) HLock drop
 item thandle @ (call) GetIText
 thandle (call) ChangedResource 
 thandle (call) HUnlock drop THEN
 item (call) HUnlock drop
 LOOP ( all messages have been updated )
 refNum (call) UpdateResFile
 dPtr (call) DisposDialog
 ELSE beep THEN
;

: fkey { | keycode -- }
 (call) frontwindow windowkind + w@ l_ext dup
 2 = swap 0< OR 0= IF 
 BEGIN 
 KeyEvent [‘] myEventRec (call) GetNextEvent UNTIL

 [‘] myEventRec message + @ $FF and -> keycode
 keycode ascii e = 
 IF edit.messages 
 ELSE
 keycode ascii 0 < keycode ascii 9 > OR
 IF beep ELSE keycode 48 - post.message
 THEN 
 THEN
 ELSE beep 
 THEN
;

( *** our standard glue routine *** )

CODE fkey.glue
 LINK A6,#-2048  ( 2K bytes of local Forth stack )
 MOVEM.L A0-A5/D0-D7,-(A7)( save registers )
 MOVE.L A6,A3    ( setup local loop return stack )
 SUBA.L #256,A3  ( starting 256 bytes below locals )
 ( no parameters are passed to the FKEY )
 JSR fkey ( call Forth routine )

 MOVEM.L (A7)+,A0-A5/D0-D7( restore registers )
 UNLK A6
 MOVE.L (A7)+,A0 ( return address )
 JMP  (A0)
END-CODE

header end

( install initial jump vector )
‘ fkey.glue ‘ start 2+ - ‘ start 2+ w!

( *** installation *** )

: make.fkey { | refNum namePtr -- }
 “ fkey.text” dup $create-res
 abort” You have to delete the old ‘fkey.text’ file first.”
 $open-res dup -> refNum call UseResFile 
[‘] start [‘] end over - call PtrToHand drop ( result code )
 “fkey 5 “ Mach2 FKEY” call AddResource
 refNum $close-res drop ( result code )
 0 “ fkey.text” 
 getvol ioVRefNum + w@ l_ext
 getfileinfo drop
 “qd15 “fkey “ fkey.text” setfileinfo
;
{2}
Listing 2: Rmaker file for the FKEY
* File fkr.R
Mach2 Fkey
FKEYQD15

Include Fkey.Text

Type DLOG
   ,2000
New Dialog
30 14 330 494
visible goAway
1
0
2000

Type DITL   
,2000
22

BtnItem
256 32 278 91
OK

StaticText
256 136 286 463  
Text FKEY © 1987 J. Langowski/MacTutor Written in Mach2™ Forth

EditText Disabled
8 32 24 464
Message 0

EditText Disabled
32 32 48 464
Message 1

EditText Disabled
56 32 72 464
Message 2

EditText Disabled
80 32 96 464
Message 3

EditText Disabled
104 32 120 464
Message 4

EditText Disabled
128 32 144 464
Message 5

EditText Disabled
152 32 168 464
Message 6

EditText Disabled
176 32 192 464
Message 7

EditText Disabled
200 32 216 464
Message 8

EditText Disabled
224 32 240 464
Message 9
 
StatText
8 8 24 28
0

StatText
32 8 48 28
1

StatText
56 8 72 28
2

StatText
80 8 96 28
3

StatText
104 8 120 28
4

StatText
128 8 144 28
5

StatText
152 8 168 28
6

StatText
176 8 192 28
7

StatText
200 8 216 28
8

StatText
224 8 240 28
9
 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Apple Pro Video Formats 2.0.2 - Updates...
Apple Pro Video Formats brings updates to Apple's professional-level codes for Final Cut Pro X, Motion 5, and Compressor 4. Version 2.0.2: Includes support for the following professional video codecs... Read more
Apple Final Cut Pro X 10.2.2 - Professio...
Apple Final Cut Pro X is a professional video editing solution.Completely redesigned from the ground up, Final Cut Pro adds extraordinary speed, quality, and flexibility to every part of the post-... Read more
Apple Compressor 4.2.1 - Adds power and...
Compressor adds power and flexibility to Final Cut Pro X export. Customize output settings, work faster with distributed encoding, and tap into a comprehensive set of delivery features. Powerful... Read more
Apple Motion 5.2.2 - Create and customiz...
Apple Motion is designed for video editors, Motion 5 lets you customize Final Cut Pro titles, transitions, and effects. Or create your own dazzling animations in 2D or 3D space, with real-time... Read more
A Better Finder Rename 10.00b1 - File, p...
A Better Finder Rename is the most complete renaming solution available on the market today. That's why, since 1996, tens of thousands of hobbyists, professionals and businesses depend on A Better... Read more
CrossOver 14.1.6 - Run Windows apps on y...
CrossOver can get your Windows productivity applications and PC games up and running on your Mac quickly and easily. CrossOver runs the Windows software that you need on Mac at home, in the office,... Read more
Printopia 2.1.14 - Share Mac printers wi...
Run Printopia on your Mac to share its printers to any capable iPhone, iPad or iPod Touch. Printopia will also add virtual printers, allowing you to save print-outs to your Mac and send to apps.... Read more
Google Drive 1.24 - File backup and shar...
Google Drive is a place where you can create, share, collaborate, and keep all of your stuff. Whether you're working with a friend on a joint research project, planning a wedding with your fiancé, or... Read more
Chromium 45.0.2454.85 - Fast and stable...
Chromium is an open-source browser project that aims to build a safer, faster, and more stable way for all Internet users to experience the web. Version 45.0.2454.85: Note: Does not contain the "... Read more
OmniFocus 2.2.5 - GTD task manager with...
OmniFocus helps you manage your tasks the way that you want, freeing you to focus your attention on the things that matter to you most. Capturing tasks and ideas is always a keyboard shortcut away in... Read more

Spirit Hunter is an Upcoming Collectible...
Boomlagoon, the team behind hybrid CCG/runner Monsu, has announced their newest project: a collectible card game/action RPG named Spirit Hunter. [Read more] | Read more »
Zen Brush 2 (Entertainment)
Zen Brush 2 1.0 Device: iOS Universal Category: Entertainment Price: $2.99, Version: 1.0 (iTunes) Description: Zen Brush 2 is a drawing app focused on the strong yet beautiful feel of the East Asian ink brush. | Read more »
NetNewsWire (News)
NetNewsWire 4.0.0 Device: iOS iPhone Category: News Price: $3.99, Version: 4.0.0 (iTunes) Description: Follow the Web NetNewsWire 4, completely written from the ground up for iPhone. NetNewsWire is the best way to keep up with the... | Read more »
Huzzah! Farming Simulator 16 Supports Cl...
As though it weren't difficult enough to resist the siren call of Farming Simulator 16, now it's been updated with cloud saves - so you can jump between devices without missing any of that precious crop-harvesting time. [Read more] | Read more »
Don't Starve: Pocket Edition Finall...
I've made no effort to hide my enjoyment of Don't Starve: Pocket Edition, but I will admit I was a tiny bit disappointed that it was only available for the iPad. Well nuts to that, because Klei Entertainment has made it universal! [Read more] | Read more »
Goat Simulator Wasn't Enough? Then...
If you just didn't get enough goat in Goat Simulator - or if you've been wanting to play a simulated MMO as a microwave - then you're in luck! Goat Simulator MMO Simulator is out now, and it's a game about simulated goats in simulated MMOs. Plus... | Read more »
You Can Play Madfinger Games' Unkil...
Madfinger Games - probably best known for the Dead Trigger series - has officially launched their newest zombie shooter (that isn't called Dead Trigger), named Unkilled. [Read more] | Read more »
KORG iELECTRIBE for iPhone (Music)
KORG iELECTRIBE for iPhone 1.0.1 Device: iOS iPhone Category: Music Price: $9.99, Version: 1.0.1 (iTunes) Description: ** 50% OFF Special Launch Sale - For a Limited Time **The ELECTRIBE reborn in an even smaller form A full-fledged... | Read more »
Toca Life: City Just Got a Bunch of New...
Toca Life: City is Toca Boca's most popular app (number 1 in 47 different countries, apparently), and it's just had an update that adds a bunch of new content. [Read more] | Read more »
My Country 3D is More About Cities than...
My Country 3D is an upcoming city builder from Game Insight that looks pretty decent - although the name seems a tad out of whack for a city builder. Ah well, it is what it is. [Read more] | Read more »

Price Scanner via MacPrices.net

DEVONthink and Co. 40% Off For Students And E...
Students and teachers are either preparing for the new semester or are already back in school. And the better organized they are the easier it is for them to concentrate on what’s really important:... Read more
Labor Day Weekend Sale: MacBook Air for up to...
Best Buy has MacBook Airs on sale for up to $150 off MSRP on their online store this weekend. Choose free shipping or free local store pickup (if available). Sale prices for online orders only, in-... Read more
BassJump Subwoofer for MacBook Refreshed...
Twelve South has released a software update for BassJump, their portable subwoofer for Macbook. BassJump 3.0 has a radically redesigned interface, and the software refresh makes the BassJump... Read more
Near-Office Input Functionality Virtually Any...
Today Logitech introduced the Logitech K380 Multi-Device Bluetooth Keyboard and the Logitech M535 Bluetooth Mouse, giving users the freedom to work on any device, most anywhere. According to... Read more
College Student Deals: Additional $100 off Ma...
Take an additional $100 off all MacBooks and iMacs at Best Buy Online with their College Students Deals Savings, valid through September 4, 2015. Anyone with a valid .EDU email address can take... Read more
2.8GHz Mac mini available for $988, includes...
Adorama has the 2.8GHz Mac mini available for $988, $11 off MSRP, including a free copy of Apple’s 3-Year AppleCare Protection Plan. Shipping is free, and Adorama charges sales tax in NY & NJ... Read more
Will You Buy An iPad Pro? – The ‘Book Mystiqu...
It looks like we may not have to wait much longer to see what finally materializes as a new, larger-panel iPad (Pro/Plus?) Usually reliable Apple product prognosticator KGI Securities analyst Ming-... Read more
eFileCabinet Announces SMB Document Managemen...
Electronic document management (EDM) eFileCabinet, Inc., a hosted solutions provider for small to medium businesses, has announced that its SecureDrawer and eFileCabinet Online services will be... Read more
WaterField Designs Unveils American-Made, All...
San Francisco’s WaterField Designs today unveiled their all-leather Cozmo 2.0 — an elegant attach laptop bag with carefully-designed features to suit any business environment. The Cozmo 2.0 is... Read more
Apple’s 2015 Back to School promotion: Free B...
Purchase a new Mac or iPad at The Apple Store for Education and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free,... Read more

Jobs Board

*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
Content Partner Engineer - *Apple* TV - App...
**Job Summary** The Apple TV team is looking for an experienced engineer with a passion for delivering first in class home entertainment solutions. The candidate will Read more
*Apple* Desktop Analyst - KDS Staffing (Unit...
…field and consistent professional recruiting achievement. Job Description: Title: Apple Desktop AnalystPosition Type: Full-time PermanentLocation: White Plains, NYHot Read more
*Apple* Retail - Multiple Customer Support P...
Job Description: Customer Support Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the Read more
*Apple* Desktop Analyst - KDS Staffing (Unit...
…field and consistent professional recruiting achievement. Job Description: Title: Apple Desktop AnalystPosition Type: Full-time PermanentLocation: White Plains, NYHot Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.