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!

Listing 1: Mach2 FKEY for text glossary
( *** Function Key example. JL June 1987 *** )

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 )
BINARY 0000000000001000 CONSTANT KeyEvent
 ( 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

: / 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 < AND 
 [‘] SavedString dup c@ btt - 1+
 + c@ post.char
 btt 1- [‘] bytesToTransfer !
 (call) tickcount [‘] lastpost !
 [‘] savedJGNEFilter @ JGNEFilter !
 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 )
 LEA  SavedJGNEFilter,A0
 MOVE.L (A0),A0  ( return address )
 JMP  (A0)

: 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

: 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 
 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 
 256 (call) NewHandle drop
 “bplt i “ Message” (call) AddResource
 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

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

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

( *** 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 )
 MOVE.L (A7)+,A0 ( return address )
 JMP  (A0)

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
Listing 2: Rmaker file for the FKEY
* File fkr.R
Mach2 Fkey

Include Fkey.Text

New Dialog
30 14 330 494
visible goAway

Type DITL   

256 32 278 91

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
8 8 24 28

32 8 48 28

56 8 72 28

80 8 96 28

104 8 120 28

128 8 144 28

152 8 168 28

176 8 192 28

200 8 216 28

224 8 240 28
Apple Inc.
Microsoft Corpora
Google Inc.

MacTech Search:
Community Search:

Software Updates via MacUpdate

Airmail 1.4 - Powerful, minimal email cl...
Airmail is a powerful, minimal mail client.It was designed to retain the same experience with a single or multiple accounts and provide a quick, modern and easy-to-use user experience. Airmail... Read more
Macs Fan Control 1.1.12 - Monitor and co...
Macs Fan Control allows you to monitor and control almost any aspect of your computer's fans, with support for controlling fan speed, temperature sensors pane, menu-bar icon, and autostart with... Read more
A Better Finder Rename 9.37 - File, phot...
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
MacBook Air EFI Firmware Update 2.9 - Fo...
MacBook Air EFI Firmware Update is recommended for MacBook Air (Mid 2011) models. This update addresses an issue where systems may take longer to wake from sleep than expected and fixes a rare issue... Read more
FileZilla - Fast and reliable FT...
FileZilla (ported from Windows) is a fast and reliable FTP client and server with lots of useful features and an intuitive interface.Version MSW: Fix installation issue with locked DLLs... Read more
OS X Yosemite 10.10 DP4 - Developer Prev...
Note: This is a Developer Preview. You must be a registered Apple Mac Developer to download this update. OS X Yosemite is Apple's newest operating system for Mac. An elegant design that feels... Read more
FinderPop 2.5.6 - Classic Mac utility, n...
FinderPop is a Universal preference pane that extends OS X's contextual menus using a FinderPop Items folder much as the Apple Menu Items folder used to do for the Apple menu. It has other features... Read more
SpiderOak 5.1.7 - Secure cloud backup, s...
SpiderOak is a multi-platform secure online backup, storage, access, and sharing solution engineered for the consumer and small businesses. You must first sign up to use SpiderOak. Running natively... Read more
Espionage 3.6 - Simple, state of the art...
Espionage offers state-of-the-art encryption and plausible deniability for your confidential data. Sometimes, encrypting your data isn't enough to protect it. That's why Espionage 3 goes beyond data... Read more
calibre 1.45.0 - Complete e-library mana...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital... Read more

Latest Forum Discussions

See All

Celebrate Summer With a Cat in the Hat L...
Celebrate Summer With a Cat in the Hat Learning Library Sale Posted by Ellis Spice on July 22nd, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
MyTaskList Review
MyTaskList Review By Jennifer Allen on July 22nd, 2014 Our Rating: :: EFFECTIVE IF PLAINUniversal App - Designed for iPhone and iPad It’s not the most stylish of task management apps, but MyTaskList has all the features you could... | Read more »
FlyCraft Herbie: Crazy Machines Review
FlyCraft Herbie: Crazy Machines Review By Jennifer Allen on July 22nd, 2014 Our Rating: :: TRICKY FLYINGUniversal App - Designed for iPhone and iPad A tough game of careful thrusting and navigation, FlyCraft Herbie: Crazy Machines... | Read more »
MTN Review
MTN Review By Jessica Fisher on July 22nd, 2014 Our Rating: :: ADORABLE, SERENE, AND AMUSINGUniversal App - Designed for iPhone and iPad MTN is an adorable, talking pet mountain that is less game and more zen garden.   | Read more »
Fly High with Ninja UP! Now Available o...
Fly High with Ninja UP! Now Available on the App Store Posted by Jessica Fisher on July 22nd, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Bio Inc. Review
Bio Inc. Review By Nadia Oxford on July 22nd, 2014 Our Rating: :: SICKENING - IN A COMPELLING WAYUniversal App - Designed for iPhone and iPad Bio Inc is about orchestrating the medical destruction of a single person. If that doesn’... | Read more »
HELMUT Review By Andrew Fisher on July 21st, 2014 Our Rating: :: TRUNDLE SIMULATOR 2014Universal App - Designed for iPhone and iPad HELMUT is a fun, fleeting time-sink that offers a momentary distraction and nothing else.   | Read more »
Walkr Review
Walkr Review By Jennifer Allen on July 21st, 2014 Our Rating: :: ORIGINAL WALKINGiPhone App - Designed for the iPhone, compatible with the iPad Walking is a bit more exciting thanks to this planet building/discovering sim reliant... | Read more »
Zombie Commando Review
Zombie Commando Review By Jennifer Allen on July 21st, 2014 Our Rating: :: MINDLESS SLAUGHTERUniversal App - Designed for iPhone and iPad Briefly fun but ultimately forgettable, Zombie Commando will scratch an itch then be... | Read more »
Swords & Poker Adventures Review
Swords & Poker Adventures Review By Jennifer Allen on July 21st, 2014 Our Rating: :: SOULLESS POKER PLAYUniversal App - Designed for iPhone and iPad Swords & Poker Adventures is a mishmash of Poker and RPGing, but it lacks... | Read more »

Price Scanner via

15-inch 2.0GHz MacBook Pro Retina on sale for...
B&H Photo has the 15″ 2.0GHz Retina MacBook Pro on sale for $1829 including free shipping plus NY sales tax only. Their price is $170 off MSRP. B&H will also include free copies of Parallels... Read more
Apple restocks refurbished Mac minis for up t...
The Apple Store has restocked Apple Certified Refurbished Mac minis for up to $150 off the cost of new models. Apple’s one-year warranty is included with each mini, and shipping is free: - 2.5GHz Mac... Read more
Twelve South HiRise For MacBook – Height-Adju...
If you use your MacBook as a workhorse desktop substitute, as many of us do, a laptop stand combined with an external keyboard and pointing device are pretty much obligatory if you want to avoid... Read more
Why The Mac Was Not Included In The Apple/IBM...
TUAW’s Yoni Heisler cites Fredrick Paul of Network World whoi blogged last week that the Mac’s conspicuous absence from Apple and IBM’s landmark partnership agreement represents a huge squandered... Read more
Save $100 on 13-inch Retina MacBook Pros, plu...
Adorama has 13″ Retina MacBook Pros on sale for $100 off MSRP. Shipping is free, and Adorama charges sales tax in NY & NJ only: - 13″ 2.4GHz/128GB MacBook Pro with Retina Display: $1199 - 13″ 2.... Read more
Blurr it 2.3 for iOS – Quickly Blurs Selected...
Hyderabad, India based TouchLabs has announced a new update of Blurr it 2.3, their photography app for iOS users. Blurr it allows you to blur part of the image to hide potentially sensitive or... Read more
MacBook Airs on sale for $100 off MSRP, start...
Best Buy has the new 2014 MacBook Airs on sale for up to $100 off MSRP on their online store. Choose free home shipping or free local store pickup (if available). Prices valid for online orders only... Read more
Amazon Announces Kindle Unlimited: Unlimited... has introduced Kindle Unlimited — a new subscription service which allows customers to freely read as much as they want from over 600,000 Kindle books, and listen as much as they want to... Read more
New Linksys Wireless Range Extenders Boost Wi...
Linksys has announced its new lineup of Linksys Wi-Fi Range Extenders. Consumers often experience a weak wireless signal in some parts of their house or apartment caused by blocking elements such as... Read more
MacBook Airs available starting at $719
The Apple Store has Apple Certified Refurbished 2013 & 2012 MacBook Airs in stock today starting at $719. An Apple one-year warranty is included with each MacBook, and shipping is free: 2013... Read more

Jobs Board

Sr Software Lead Engineer, *Apple* Online S...
Sr Software Lead Engineer, Apple Online Store Publishing Systems Keywords: Company: Apple Job Code: E3PCAK8MgYYkw Location (City or ZIP): Santa Clara Status: Full Read more
*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
*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
Sr *Apple* Engineer - IT - Requisition #: -...
For more information about TIAA-CREF, visit our website . The Apple Engineer will provide engineering and third-level incident support for 300- 500 MacOS desktop/laptop Read more
*Apple* Systems Administrator - DISH (United...
…satellite service provider, and Dish is currently looking for an experienced Apple /Mac Systems Administrator. Apple systems administrator will be responsible for Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.