TweetFollow Us on Twitter

Threaded News
Volume Number:6
Issue Number:5
Column Tag:Jörg's Folder

Threaded News

By Jörg Langowski, MacTutor Editorial Board

MacForth Plus 4.0; NEON news

And here we are back with a “real” Forth column again. Just in time, it seems; only when I read on GEnie recently “It is too bad that he was seduced by the dark side of the force” about my recent excursions into other domains I realized that the true believers might have been disappointed. But please realize, there is only so much space in our magazine, and we have to try and cover a great variety of subjects.

A new version of MacForth Plus (v 4.0) has arrived here; with lots of improvements, notably faster execution and compilation, the possibility to generate stand-alone code, and some rudimentary but very efficient object-oriented extensions. Before I tell you more about it, I’d like to show you that there are still some people out there using NEON, and improving it. I received the following note from a reader in Australia:

“Dear Jörg,

I was delighted to read in your October column in MacTutor, that some people are still using NEON. I thought I was the only one! I enclose a copy of a letter I have sent to Bob Loewenstein, for your interest.

Yours sincerely,

Michael Hore

5/137 Elouera Rd.

Cronulla, NSW 2230, Australia”.

The copy of Mike’s letter follows:

“Dear Bob,

I’ve just read your comments on NEON in the October issue of MacTutor (which takes a while to arrive on the newsstands here). I was amazed (and delighted) to see that there are still a number of folks using NEON - I thought I might be the only one! I have always thought that this was the most underrated development system for the Mac. A good product with potential to be a great one, but torpedoed by a marketing strategy which bordered on the nonexistent.

I also found no problem running on a Mac II - my personal finances don’t run to one, but I had a report that an application that I wrote in NEON worked OK on a Mac II. Like you I found I had to set a larger stack size than the default - unless I set at least 7K I got random crashes, usually during Standard File calls. Maybe this was the cause of the problems others ran into.

I also started to develop NEON, but thinking I was about the only user I took a more radical line than you - I completely reimplemented the nucleus from scratch. It now compiles subroutine-threaded code, with optimized native code for common sequences. The result is that applications run 4-5 times faster, and are about 10% smaller. The compilation speed is now over 1000 LPM. The whole assembler compiles in about a minute. I’ve also introduced quite a few improvements to the high-level code - at least I think they are improvements. Multiple inheritance, for example. I thought the changes were radical enough to justify a change of name, so now I’m calling it Mops (Michael’s Object-oriented Programming System!)

My understanding of copyright legalities is that the Mops nucleus, being completely new, would not violate Kriya’s copyright on NEON. That is unless a language, as such, is copyrightable, rather than the specific code which comprises a specific implementation. I think it probably isn’t copyrightable, but I’m not a lawyer. But since I haven’t changed all the high-level code, Kriya still definitely hold the copyright to that (unless you were able to persuade them to release it into the public domain - how did you get on?). But I’m quite happy to send Mops to anyone who has NEON, since that doesn’t involve legal problems. In any case, I don’t have the time or inclination to document Mops from scratch for someone unfamiliar with NEON. I will produce a file listing the changes between Mops and NEON, if anyone wants Mops. If I’m the copyright holder on the Mops nucleus, my only conditions are that it not be used for commercial purposes without my permission.

So if you or any other NEON users are interested in giving Mops a try, just write me, or better, send me a disk with some of your NEON developments on it, and I’ll send it back to you with Mops. Sorry for the horse and buggy method, but distance precludes electronic transfer. Perhaps you could do me a favor and post some of this letter on some appropriate bulletin board, in case anyone might be interested.

Of course, if your NEON code makes much use of implementation details of NEON, like expecting certain things to be at CFAs or whatever, it won’t work under Mops without rewriting. Also, I took a different line on floating point. Actually, this was only experimental since I don’t need FP in my work - it’s all string handling. NEON FP is very implementation-dependent, so a fair bit of work would have to be done to get existing FP code to work under Mops. But it certainly could be done.

Apart from that, the main differences from NEON are in the direction of improving the error checking, and also in bringing the underlying Forth more in line with Forth 83 and the forthcoming ANSI standard. Most of the necessary changes to NEON code can be done semi-mechanically. I found the most troublesome was the change in boolean “true” from 1 to -1. If you don’t often do arithmetic on booleans, you won’t have much trouble.

I’ve also tried to make Mops 32-bit clean, and it seems to work OK on new Macs. At least it worked on a friend’s SE/30 (which cheered me up, and slightly compensated for the green colour of my face).

I haven’t had time yet to update all the various NEON utilities, or the classes that I don’t actually use. But I have updated all the standard stuff, implemented a modeless dialog class, and written a new decompiler/debugger. I also have code that will read and write formatted Microsoft Word documents, if that’s any use to anybody.

Looking forward to hearing from you,

Yours sincerely,

Michael Hore.”

I have checked back with Bob Loewenstein <rfl@tycho.yerkes. uchicago. edu>, who is sending me his NEON extensions for review. You’ll hear about it in one of the next columns. It also seems that Kriya is still planning to release NEON into the public domain, but that there were some legal problems that had to be fixed before they could actually go ahead with it. There may be a chance that NEON is actually public domain at the time you read this.

MacForth 4.0

It is a long time since I wrote something about MacForth; that was when version 3.53 came out. Mainly because of the closer machine-orientation of Mach2, and also due to my non-access to Compuserve’s MacForth forum, I preferred to write my Forth examples in Mach2. Also, we had hardly any feedback from the MacForth community in the form of articles we could publish. However, that does not mean that Creative Solutions and the MacForth users group have been asleep. Just now, a thick binder with the 4.0 manual and diskettes arrived here, and I’ll give you some of my impressions. I cannot possibly cover all the features here, because of sheer quantity; I’ll only talk about the important new improvements. The two changes that are most visible compared to the previous version (3.53) are the support of stand-alone code, and active elements, a sort of object orientation.

Stand-alone code

The great advantage of Mach2 over MacForth has always been that Mach2 created true 68000 code through its subroutine-threading mechanism. Therefore, it was easily possible to create stand-alone code resources in Forth, as we have seen in various examples of XCMDs, MDEFs, FKEYs and DRVRs. A token-threaded Forth like MacForth has much greater difficulties to create stand-alone code, because the Forth code needs an interpreter to be executed.

Fortunately, MacForth’s interpreter is very small, it consists of two instructions:

 MOVE.W (A2)+,D3
 JMP  0(A6,D3.W)

where A2 is the instruction pointer and A6 contains the base address of the MacForth kernel. The interpreter, the token-threaded Forth code, and some entry and exit code together will constitute a stand-alone code resource (SA) which can - for instance - be called by a toolbox routine which requires a filter procedure.

The process of creating SAs is very simple. Let’s assume you have a Forth definition that you want to convert into an SA, such as

: beeper 10 sysbeep ;

After loading the SA maker file (which contains all the source to the SA compiler), you simply type SA beeper. This initiates a rather complicated process, where the Forth definition is analyzed: a list is created of all tokens used, and the definitions of all these tokens copied into the target area. Of course, this process is recursive, because the copied tokens may call other tokens, etc. The token values of all definitions have to be changed during this process, because tokens are actually offset addresses from the base of the kernel, and all those offsets will have changed.

One can follow the compilation process when the debug option is on; a message will be printed out as each Forth word is copied into the target area and the token addresses are changed.

The stand-alone support code included with MacForth is very complete; examples are given for I/O (Forth I/O does not work from SAs, of course), floating point handling, and debugging. Other files contain code used for generating drivers/DAs and XCMDs/XFCNs. For the latter, interfaces are also given to the Hypercard XCMD callback routines.

A simple example of an XCMD which beeps a number of times depending on the first parameter is given below:

\ 1

: nbeep \ MacForth XCMD to beep n times
 paramCount 0= IF 0 return EXIT THEN
 0 locals| HANDLE |
 0 param -> handle
 handle lock.handle
 handle h@  \ convert to address
 xcmdPad ZeroToPas \ convert to Pascal string
 xcmdPad StrToNum  \ convert to a number
 0 do 10 sysbeep loop\ beep n times
 handle unlock.handle
 handle dispose.handle
 0 return
;

To convert this code into an XCMD, you simply type

--2

xcmd nbeep
2000 “ nbeep” store.xcmd

and the XCMD resource will be left in the “Resource Bag” file where all standard resources of MacForth are stored. Included on the source code disk is a Hypercard stack with which you can try out this XCMD.

Actels - a simple OOP system

MacForth 4.0 now includes support for a simple late-binding message-passing mechanism to objects, which CSI calls actels (short for active elements). Like classical objects, actels are data structures bundled with the procedures that operate on the data. When messages are passed to an actel, an appropriate procedure will be invoked, depending on the message; when no method corresponding to the message can be found, the message is passed on to the parent object in the hierarchy. So far, just like standard object-oriented behavior; the difference is that the behavior of an actel is much less defined initially than that of objects in other languages. For instance, classes as such don’t really exist; to create a new class of actels, you define a prototype, which should be copied and initialized when it receives the >>New message. It is up to you to define this behavior; there is no generic ‘object class’ for which some default behavior is implemented.

To make this more understandable, let me describe how the example on the MacForth disk implements matrix actels. First, a data structure is defined, which contains a 16 byte header and cells that hold the row and column size; no space for storing the data is defined yet:

\ 3

structure MATRIXHEADER
 minElemHeaderSize + \ generic header info
 short: +#ROWS   \ number of rows
 short: +#COLS   \ number of columns
 0 bytes: +DATA  \ variable amount of data
structure.end

The first four bytes of the header contain a jump to the method selector corresponding to the actel. The data following the header are the instance variables; the length of the instance variable list is stored in the header. You are responsible for initializing the actel prototype, which means storing the jump to the method selector and the instance variable length in the header, and initializing the other variables.

Messages to actels and the corresponding methods can be defined very simply: each message corresponds to a number, but normally you don’t need to know that number once the message is defined. For example, the messages to the matrix actels are defined as follows:

2000 message >>RC@
2001 message >>RC!
2002 message >>M+
2003 message >>M*

As a convention, names of messages start with “>>”.

Selectors for matrix actels would look somewhat like the following. First, we define the low-level methods that respond to some default messages, their numbers start with 1:

\ 4

1 selector: LowWMatrix    ElemPanic\ no parent
 WMatNew\ >>New
 to.heap\ >>Discard 
 drop   \ >>Empty 
 inherited  \ >>Room 
;selector

The first element in the list is the name of the method that is invoked when the message can’t be handled by this actel. Since there is no parent object, we use the generic ElemPanic procedure, which displays an error message. Messages number 1-4 are predefined by MacForth, but their behavior is not; the next four elements in the selector list are Forth words that define the behavior.

Similarly, we define a selector list for our newly defined messages to matrix actels, their numbers start with 2000:

\ 6

2000 selector: HighWMatrix
 LowWMatrix \ parent
 RCW@  RCW!  M+   M*
 \ see message descriptions above
;selector

The header of our matrix actel prototype must then contain a jump to the highest-level selector, HighWMatrix.

When a new instance of an actel is created, the header and instance variables are copied into a new heap object of the appropriate size. That heap object can then be re-sized, for instance to accommodate more rows and columns.

Methods are invoked on actels by pushing the actel’s handle on the stack and calling the message: for instance a b >>M+ for adding the matrices a and b.

You see from this brief overview that actels in MacForth Plus provide a very general way of implementing object-oriented behavior; the ‘disadvantage’ is that much of the details are left to the programmer, but I see this rather as a great advantage since it offers great flexibility in defining the behavior of objects. Very Forth-like, because a. it restricts the programmer in the least possible way and b. of course, it will allow you to do the most stupid things without great difficulty. But then, if you want a safety net, you can always resort to C++

Speed

Speed of code execution, as you recall, has always been one of my major concerns in judging development systems on the Mac. Therefore, the overview of MacForth would not be complete without giving you the results of some benchmarks. The good news is that MacForth now comes close to Mach2 in execution speed, the bad news of course that it is not quite there yet. You have to pay a price for token-threaded code. Nevertheless, the Sieve benchmark - with local variables and some optimized words - executes in 2.9 seconds on a MacIIx. Mach2, with its built-in words, takes 2.0 seconds. If one optimizes the sequences i c@ , 0 i c! , and i + in Mach2 by defining the code words ic@ , 0ic! , and i+ like in MacForth, Mach2 will take 1.95 seconds - the built-in optimization of Mach2 is quite good. Under MacForth, the sieve version without the optimized words executes in 3.6 seconds.

Floating point execution speed, which has been a major concern for the previous version of MacForth, has now been greatly improved; a 68881 version of the floating point words is included, and now there is almost no speed difference for executing standard floating point operations between Mach2 and MacForth. The old MacForth floating point routines which use the SANE package, however, still have quite some overhead for empty loops.

Compilation speed in MacForth Plus is very fast; I see a noticeable difference to the old version, and the documentation says there is an increase in speed by a factor of 3-5. Part of this improvement is because of changes in the vocabulary structure; vocabularies have a completely new internal structure, they are hash-coded and are actel, thus inserting a new word into a vocabulary means sending a message to it. These vocabularies are much smarter than the previous ones; for instance, they automatically resize themselves when they run out of space.

Conclusion

There are many more improvements in the new MacForth, but these are the major ones. Stand-alone code, a domain previously only covered by Mach2 Forth, can now be created by MacForth as well, and there are very efficient tools provided with the system to help programming such stand-alone code. Together with the object-orientation mechanism provided by the actels, and the great variety of programming aids and examples provided, MacForth’s new version provides one of the best compromises between versatility, speed of development and speed of execution that I know of in a Macintosh development system. Of course, any Forth programmer will affirm that only a Forth development system will be able to offer such a good balance between flexibility, simplicity and speed, (everybody here knows that’s my opinion, anyway), but that’s another story. My personal preference for ‘close-to-the-toolbox’ programming still remains Mach2, also because of its good assembler, but for Forth programmers who prefer a very extensive set of words and tools that provide a very high-level access to the Macintosh, MacForth is the system of choice. CSI’s user support, through upgrades, newsletters, and the Compuserve Forth forum, is excellent, and if the examples on the MacForth disks don’t satisfy you, you can find orders of magnitude more on Compuserve. If only Palo Alto Shipping’s Mach2 support on GEnie were a little more active lately, one hasn’t heard much of them.

Anyway, you see, the Forth is still with us.

 
AAPL
$100.96
Apple Inc.
-0.83
MSFT
$47.52
Microsoft Corpora
+0.84
GOOG
$596.08
Google Inc.
+6.81

MacTech Search:
Community Search:

Software Updates via MacUpdate

Airfoil 4.8.9 - Send audio from any app...
Airfoil allows you to send any audio to AirPort Express units, Apple TVs, and even other Macs and PCs, all in sync! It's your audio - everywhere. With Airfoil you can take audio from any... Read more
WhatRoute 1.13.0 - Geographically trace...
WhatRoute is designed to find the names of all the routers an IP packet passes through on its way from your Mac to a destination host. It also measures the round-trip time from your Mac to the... Read more
Chromium 37.0.2062.122 - 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. FreeSMUG-Free OpenSource Mac User Group build is... Read more
Attachment Tamer 3.1.14b9 - Take control...
Attachment Tamer gives you control over attachment handling in Apple Mail. It fixes the most annoying Apple Mail flaws, ensures compatibility with other email software, and allows you to set up how... Read more
Duplicate Annihilator 5.0 - Find and del...
Duplicate Annihilator takes on the time-consuming task of comparing the images in your iPhoto library using effective algorithms to make sure that no duplicate escapes. Duplicate Annihilator detects... Read more
jAlbum Pro 12.2 - Organize your digital...
jAlbum Pro has all the features you love in jAlbum, but comes with a commercial license. With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code!... Read more
jAlbum 12.2 - Create custom photo galler...
With jAlbum, you can create gorgeous custom photo galleries for the Web without writing a line of code! Beginner-friendly, with pro results Simply drag and drop photos into groups, choose a design... Read more
Quicken 2015 2.0.4 - Complete personal f...
Quicken 2015 helps you manage all your personal finances in one place, so you can see where you're spending and where you can save. Quicken automatically categorizes your financial transactions,... Read more
iMazing 1.0 - Complete iOS device manage...
iMazing (formerly DiskAid) is the ultimate iOS device manager with capabilities far beyond what iTunes offers. With iMazing and your iOS device (iPhone, iPad, or iPod), you can: Copy music to and... Read more
Xcode 6.0.1 - Integrated development env...
Apple Xcode is Apple Computer's integrated development environment (IDE) for OS X. The full Xcode package is free to ADC members and includes all the tools you need to create, debug, and optimize... Read more

Latest Forum Discussions

See All

View Source – HTML, JavaScript and CSS...
View Source – HTML, JavaScript and CSS 1.0 Device: iOS Universal Category: Utilities Price: $.99, Version: 1.0 (iTunes) Description: View Source is an app plus an iOS 8 Safari extension that makes it easy to do one key web developer... | Read more »
Avenged Sevenfold’s Hail To The King: De...
Avenged Sevenfold’s Hail To The King: Deathbat is Coming to iOS on October 16th Posted by Jessica Fisher on September 19th, 2014 [ permalink ] Just in time for Halloween, on October 16 Avenged Sevenfold will be launching | Read more »
Talisman Has Gone Universal – Can Now be...
Talisman Has Gone Universal – Can Now be Played on the iPhone Posted by Jessica Fisher on September 19th, 2014 [ permalink ] | Read more »
Tap Army Review
Tap Army Review By Jennifer Allen on September 19th, 2014 Our Rating: :: SHOOT EM ALLUniversal App - Designed for iPhone and iPad Mindless but fun, Tap Army is a lane-based shooter that should help you relieve some stress.   | Read more »
Monsters! Volcanoes! Loot! Epic Island f...
Monsters! Volcanoes! Loot! | Read more »
Plunder Pirates: Tips, Tricks, Strategie...
Ahoy There, Seadogs: Interested in knowing our thoughts on all this plundering and pirating? Check out our Plunder Pirates Review! Have you just downloaded the rather enjoyable pirate-em-up Plunder Pirates and are in need of some assistance? Never... | Read more »
Goat Simulator Review
Goat Simulator Review By Lee Hamlet on September 19th, 2014 Our Rating: :: THE GRUFFEST OF BILLY GOATSUniversal App - Designed for iPhone and iPad Unleash chaos as a grumpy goat in this humorous but short-lived casual game.   | Read more »
A New and Improved Wunderlist is Here fo...
A New and Improved Wunderlist is Here for iOS 8 Posted by Jessica Fisher on September 19th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Evernote Update for iOS 8 Adds Web Clipp...
Evernote Update for iOS 8 Adds Web Clipping, Quick Notes, and More Posted by Ellis Spice on September 19th, 2014 [ permalink ] | Read more »
Apple Names Ultimate Productivity Bundl...
Apple Names Ultimate Productivity Bundle by Readdle as the Essential Bundle on the App Store Posted by Jessica Fisher on September 19th, 2014 [ permalink | Read more »

Price Scanner via MacPrices.net

Updated Price Trackers
We’ve updated our Mac Price Trackers with the latest information on prices, bundles, and availability on systems from Apple’s authorized internet/catalog resellers: - 15″ MacBook Pros - 13″ MacBook... Read more
Mac Pros available for up to $260 off MSRP
Adorama has Mac Pros on sale for up to $260 off MSRP. Shipping is free, and Adorama charges sales tax in NY & NJ only: - 4-core Mac Pro: $2839.99, $160 off MSRP - 6-core Mac Pro: $3739.99, $260... Read more
13-inch 2.6GHz/256GB Retina MacBook Pros avai...
B&H Photo has the 13″ 2.6GHz/256GB Retina MacBook Pro on sale for $1379 including free shipping plus NY sales tax only. Their price is $120 off MSRP. Read more
Previous-generation 15-inch 2.0GHz Retina Mac...
B&H Photo has leftover previous-generation 15″ 2.0GHz Retina MacBook Pros now available for $1599 including free shipping plus NY sales tax only. Their price is $400 off original MSRP. B&H... Read more
21″ 2.7GHz iMac available for $1179, save $12...
Adorama has 21″ 2.7GHz Hawell iMacs on sale for $1179.99 including free shipping. Their price is $120 off MSRP. NY and NJ sales tax only. Read more
iOS 8 Adoption Rate Slower than iOS 7, 6, Hit...
Apple began pushing out iOS 8 updates to eligible devices around 1pm ET on September 17, 2014. However, unlike with iOS 7, which boasted a wide variety of differences from its predecessor iOS 6, in... Read more
LIkely Final Definitive OS X 10.9.5 Mavericks...
Apple has released what will almost certainly be the last incremental version number update of OS X 10.9 Mavericks (save for futire security updates) before OS X 10.10 Yosemite is released next month... Read more
Fingerprints, Apple Pay and Identity Theft Wa...
On Sep 9th, CEO Tim Cook unveiled Apple Pay, along with the new iPhone 6 and iWatch. Apple Pay is a newly developed technology that utilizes a near field communication (NFC) to enable customer... Read more
Amazon Introduces Two All-New Kindles
Amazon on Thursday introduced the 7th generation of its Kindle dedicated e-reader device: Kindle Voyage, its top-of-the-line e-reader, and the new $79 Kindle, with a 20% faster processor, twice the... Read more
Save up to $300 on the price of a new Mac wit...
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
Project Manager, *Apple* Financial Services...
**Job Summary** Apple Financial Services (AFS) offers consumers, businesses and educational institutions ways to finance Apple purchases. We work with national and 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
*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
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.