TweetFollow Us on Twitter

MacPerl: Dev Overview

Volume Number: 14 (1998)
Issue Number: 2
Column Tag: Alternative Environments

MacPerl: A Developer's Overview

by Rich Morin

The Power of Perl, the ease of Macintosh

Overview

Perl (and, by extension, MacPerl) is a convenient and powerful language for administrative programming, CGI scripting on the World Wide Web, data analysis and filtering (such as error checking and reformatting), network programming, and more. In short, Perl can be used for almost any programming project you may have in mind.

On Unix systems, Perl is well on its way toward taking over all substantial scripting functions, supplanting traditional tools such as sh, awk, and sed. On Macintosh systems, Perl can be used just as readily (with the added attraction that there is nothing to "unlearn").

Perl was created ten years ago when its author, Larry Wall, decided that existing scripting languages were insufficiently powerful for the distributed, bug reporting project he was working on. Seeing the potential in his new tool, Larry was gracious enough to release Perl as freeware (freely redistributable software in source and binary forms).

Other programmers picked it up, tried it, liked what they saw, and suggested enhancements and modifications. In a few years, Perl grew substantially in capabilities and in adherents, and was well on its way to becoming one of the most powerful and popular computer languages in use today. Although Perl was originally written for the Unix operating system, it has since been ported to many different systems.

The recent rise in popularity of the World Wide Web has assured the popularity of Perl for some time to come. Perl is not a "strongly-hyped language" like Java, but it has shown itself to be an indispensible tool for creating and maintaining Web sites. Perl is used for CGI scripting, site management, and many other duties.

MacPerl (ported by Matthias Neeracher) has also been in existence for several years, but its popularity has not increased at the same rate, and certainly not to the level I feel it deserves. The Macintosh is a friendly, easy to use, and very popular computer system. MacPerl is an elegant and friendly Macintosh adaptation of an extraordinarily powerful (and popular) programming language. Why hasn't it taken off as quickly as Perl has?

Many potential MacPerl users are unaware that Perl (let alone a Macintosh version) exists! Most Macintosh magazines, rightly or wrongly, shy away from programming articles. Also, lacking any commercial reference material or distribution CD for MacPerl, many prospective users may have felt apprehensive about getting involved. PTF's MacPerl product (and articles like this one!) should resolve these issues, helping the community to grow substantially.

Language Summary

Perl syntax and fundamental capabilities are reminiscent of those found in C. The following bit of code, for instance, would work in either language:

printf("hello, world\n");

Ignoring a few dollar signs (indicating that the keyword is being used to name a scalar variable), most Perl code looks quite a bit like C code:

$cnt=$sum=0;
for ($i=$lo; $i<$hi; $i++) {
  if ($xyz[$i] >= 0) {
    $cnt++;
    $sum += $xyz[$i];
  }
}
printf("\$cnt=%d, \$sum=%d\n", $cnt, $sum);

Perl adds syntax and capabilities from several other languages, however. Here are some Perl commands that might be more familiar to an awk, sed, or shell scripter:

$month = $months{"Jan"};    # hash (associative array)
$upper =~ tr/[a-z]/[A-Z]/;  # character substitution
$path  =~ s@/@:@g;          # regular expression
$wd   = `pwd`;              # subprocess invocation
$cfile = "$base.c";         # variable interpolation
print "hello, world\n";     # unformatted print command

In fact, the basic Perl language offers a wealth of features unmatched in any other popular programming language, including:

  • anonymous functions, defined at run-time
  • arbitrary-length strings and data structures
  • associative (possibly persistent) arrays (hashes)
  • automatic garbage collection
  • compound data structures (such as queues of arrays)
  • dynamic storage allocation
  • file name globbing (wild card expansion)
  • late binding of data and functions
  • lists: deque, queue, indexed array, stack, and more
  • coercion between numbers and strings
  • object-oriented features (such as inheritance)
  • regular expressions for matching and substitution
  • run-time evaluation of arbitrary code
  • run-time tracing and control of external data
  • sparse arrays (indexed and hashed)

The core language is supplemented by a wide variety of predefined objects. Some of these are included in the base distribution; others can be found on the Comprehensive Perl Archive Network (CPAN), an international set of FTP mirror sites. By looking around a little, you can find objects for arbitrary-precision arithmetic, CGI scripting, genetic sequence manipulation, network administration... well, you get the idea.

Perl's language features and object definitions work together in very powerful ways. A Perl-based CGI script can, quite trivially

  • accept information from a user, checking it for validity
  • retrieve data from selected files or a remote database
  • perform arbitrary, user-specified calculations on the data
  • generate a graph from the results, storing it as an image file
  • output HTML to display the graph, with annotations

What's more, this entire operation can be performed in a demonstrably secure manner, using Perl's mechanisms for data-flow tracing, safe run-time evaluation of code, and more.

Macintosh Ease of Use

MacPerl can run as an application under the Finder or as a tool under MPW. Because most Mac users do not have MPW, the Finder version tends to dominate. I am told, however, that the MPW version acts much like any other MPW tool, supporting command-line options, ToolServer, etc.

The MacPerl application normally operates as an interactive development environment, displaying edit and interaction windows. When a MacPerl document (script) is double-clicked, it will either start up an edit/debug session or a batch program, depending on a user-definable preference. It also is possible to create "droplets", MacPerl scripts which support the Macintosh drag-and-drop protocol.

MacPerl has a built-in text editor, but it also works well with text editors such as Alpha and BBEdit. Both directly and by means of an Apple Script interface, MacPerl programs can emit and receive Apple events. Because of its interpretive nature, MacPerl provides a pleasant way to interface with the Toolbox (prototyping Dialog Boxes and such).

Although a Perl compiler is under development, current Perl implementations use a hybrid compiler-interpreter. The Perl source code is syntax-checked and parsed, but not turned into the host system's machine language. This approach allows Perl scripts to start up quickly and still run at a reasonable speed. A Perl script typically runs within a factor of three of the speed of a compiled C program.

Legal Issues

MacPerl (like Perl) is free software; it may be used, modified, and redistributed under the terms of the Perl Artistic License. This license, crafted by Larry Wall, is quite flexible. It allows commercial and non-commercial distribution of the program, with fairly minor restrictions. See the license text (included with the distribution) for specific details.

Please note that this definition of "free software" is far broader than that used by many Macintosh "freeware" applications. The fact that MacPerl is available in source code allows any interested party to look over its construction and modify its behavior. This has had a great deal to do with the growth and overall robustness of MacPerl and Perl.

Porting Issues

Perl comes from the Unix community, which does some things rather differently than the Mac OS community. Where possible, MacPerl makes accomodations, providing "reasonable" behavior. In some cases, however, Unix-derived code will have to be tweaked before it can be used. Finally, some kinds of Perl applications are totally unsuited for use on a Macintosh.

The Macintosh uses a carriage return (\015), rather than Unix's line feed (\012), to separate lines of text. MacPerl accomodates this by emitting a carriage return when a newline (\n) is specified (requests for \015 are, however, taken literally). Similarly, when reading line-oriented text, MacPerl expects a carriage return, rather than a line feed.

As a result, MacPerl does not accept line feeds as delimiters in its input programs or data files. If you want to use a Unix-derived Perl script or textual data file under MacPerl, you must first convert all of its carriage returns to newlines. This is trivial, if slightly annoying.

File naming syntax must also be converted. Slashes (/) must be changed into colons (:), full path names must be modified to include disk names, etc. In addition, if the Unix code depends on "special" files (/dev/*, /proc/*, and such), some modifications will be needed.

Unix supports preemptive multitasking, allowing (nay, encouraging) programmers to invoke separate programs whenever this seems appropriate. Perl follows in this pattern, giving programmers many ways (backquotes, exec, fork, pipes, and such) to start up other processes.

MacPerl makes a few accomodations to multitasking. Certain backquoted commands (such as `pwd`) are silently emulated, handling common Unix idioms. Some multitasking may be performed if ToolServer is present. (Of course, the requested program also must be available!) Code which depends strongly on multitasking may not port smoothly, however, even with the aid of the ToolServer. If you find such a Perl script, you should expect to rework it quite a bit before you can use it on a Mac.

Some Unix-derived Perl scripts will not port readily. Code which depends on multi-tasking may not port smoothly, even with the aid of ToolServer. Code that depends on Unix-specific system calls must be modified or eliminated.

Finally, some Perl scripts rely on binary extensions which are linked into the Perl interpreter at run time. Only a few of these extensions have been ported to MacPerl, so these scripts are unlikely to work without a lot of effort (and Perl-specific knowledge).

MacPerl Resources

The MacPerl Pages http://www.ptf.com/macperl/ are a centralized source of information on MacPerl. They contain information on MacPerl, links to online resources, forms for joining the MacPerl mailing list and submitting materials (such as code samples and war stories), and more.

All modesty aside, the definitive work on MacPerl is "MacPerl: Power and Ease" (Prime Time Freeware, 1998, ISBN 1-881957-32-2, $40 MSRP). This product combines a 350+ page introductory and reference manual with a MacPerl distribution CD-ROM. For more information, visit the Prime Time Freeware web site http://www.ptf.com/.

Perl is served by two main web sites: http://www.perl.com and http://www.perl.org. Try these sites before doing any sort of search: if you can't find what you want through one or the other of these sites, it probably doesn't exist on the Internet. Though there are quite a few books in print on Perl and related subjects, the three definitive books are published by O'Reilly & Associates:

  • Learning Perl, Second Edition, by Randal L. Schwartz, Tom Christiansen, 1996, ISBN 1-56592-284-0.
  • Programming Perl, Second Edition, by Larry Wall, et al, 1996, ISBN 1-56592-149-6.
  • Advanced Perl Programming by Sriram Srinivasan, 1997, ISBN 1-56592-220-4.

A 30-year veteran of the computer industry, Rich Morin rdm@ptf.com writes the I/Opener column for SunExpert magazine. His desktop system, Cerberus, is a three-headed Power Mac, networked to several Unixish (FreeBSD, MkLinux, Rhapsody, Solaris, and SunOS) systems.

Rich is also the president of Prime Time Freeware http://www.ptf.com/, which publishes mixed-media (book/CD-ROM) collections of freely redistributable software. PTF's Mac-specific products include MacPerl: Power and Ease and MkLinux: Microkernel Linux for the Power Macintosh. This article contains material adapted from PTF's MacPerl book.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Tidy Up 5.3.7 - Find duplicate files and...
Tidy Up is a full-featured duplicate finder and disk-tidiness utility. Features: Supports Lightroom: it is now possible to search and collect duplicates directly in the Lightroom library. Multiple... Read more
Pinegrow 5.97 - Mockup and design web pa...
Pinegrow (was Pinegrow Web Designer) is desktop app that lets you mockup and design webpages faster with multi-page editing, CSS and LESS styling, and smart components for Bootstrap, Foundation,... Read more
BlueStacks 4.210.0 - Run Android applica...
BlueStacks App Player lets you run your Android apps fast and fullscreen on your Mac. Feature comparison chart How to install Bluestacks on your Mac Go to MacUpdate and click the green "Download"... Read more
WhatsApp 2.2027.10 - Desktop client for...
WhatsApp is the desktop client for WhatsApp Messenger, a cross-platform mobile messaging app which allows you to exchange messages without having to pay for SMS. WhatsApp Messenger is available for... Read more
Art Text 4.0.1 - $29.99
Art Text is graphic design software specifically tuned for lettering, typography, text mockups and various artistic text effects. Supplied with a great variety of ready to use styles and materials,... Read more
Adobe Dreamweaver CC 2020 20.2 - Build w...
Dreamweaver CC 2020 is available as part of Adobe Creative Cloud for as little as $20.99/month (or $9.99/month if you're a previous Dreamweaver customer). Adobe Dreamweaver CC 2020 allows you to... Read more
Adobe Acrobat DC 20.009.20074 - Powerful...
Acrobat DC is available only as a part of Adobe Creative Cloud, and can only be installed and/or updated through Adobe's Creative Cloud app. Adobe Acrobat DC with Adobe Document Cloud services is... Read more
beaTunes 5.2.10 - Organize your music co...
beaTunes is a full-featured music player and organizational tool for music collections. How well organized is your music library? Are your artists always spelled the same way? Any R.E.M. vs REM?... Read more
DiskCatalogMaker 8.1.5 - Catalog your di...
DiskCatalogMaker is a simple disk management tool which catalogs disks. Simple, light-weight, and fast Finder-like intuitive look and feel Super-fast search algorithm Can compress catalog data for... Read more
Meteorologist 3.4.1 - Popular weather ap...
Meteorologist is a simple interface to weather provided by weather.com. It provides the ability to show the weather in the main menu bar, displaying more detail in a pop-up menu, whose contents are... Read more

Latest Forum Discussions

See All

Steam Link Spotlight - Disco Elysium
Steam Link Spotlight is a feature where we look at PC games that play exceptionally well using the Steam Link app. Our last entry was Signs of the Sojourner Read about how it plays using Steam Link over here. | Read more »
Distract Yourself With These Great Mobil...
There’s a lot going on right now, and I don’t really feel like trying to write some kind of pithy intro for it. All I’ll say is lots of people have been coming together and helping each other in small ways, and I’m choosing to focus on that as I... | Read more »
Pokemon Go's July Community Day wil...
Pokemon Go developers have announced the details concerning the upcoming Gastly Community Day. This particular event was selected by the players of the game after the Gas Pokemon came in second place after a poll that decided which Pokemon would... | Read more »
Clash Royale: The Road to Legendary Aren...
Supercell recently celebrated its 10th anniversary and their best title, Clash Royale, is as good as it's ever been. Even for lapsed players, returning to the game is as easy as can be. If you want to join us in picking the game back up, we've put... | Read more »
Detective Di is a point-and-click murder...
Detective Di is a point-and-click murder mystery set in Tang Dynasty-era China. You'll take on the role of China's best-known investigator, Di Renjie, as he solves a series of grisly murders that will ultimately lead him on a collision course with... | Read more »
Dissidia Final Fantasy Opera Omnia is se...
Dissidia Final Fantasy Opera Omnia, one of Square Enix's many popular mobile RPGs, has announced a plethora of in-game events that are set to take place over the summer. This will include several rewards, Free Multi Draws and more. [Read more] | Read more »
Sphaze is a neat-looking puzzler where y...
Sphaze is a neat-looking puzzler where you'll work to guide robots through increasingly elaborate mazes. It's set in a visually distinct world that's equal parts fantasy and sci-fi, and it's finally launched today for iOS and Android devices. [... | Read more »
Apple Arcade is in trouble
Yesterday, Bloomberg reported that Apple is disappointed in the performance of Apple Arcade and will be shifting their approach to the service by focusing on games that can retain subscribers and canceling other upcoming releases that don't fit... | Read more »
Pixel Petz, an inventive platform for de...
Pixel Petz has built up a sizeable player base thanks to its layered, easy-to-understand creative tools and friendly social experience. It revolves around designing, trading, and playing with a unique collection of pixel art pets, and it's out now... | Read more »
The King of Fighters Allstar's late...
The King of Fighters ALLSTAR, Netmarble's popular action RPG, has once again been updated with a plethora of new content. This includes battle cards, events and 21 new fighters, which increases the already sizeable roster even more. [Read more] | Read more »

Price Scanner via MacPrices.net

$219 Apple AirPods Pro are back at Verizon, s...
Verizon has Apple AirPods Pro on sale again for a limited time for $219.99 on their online store. Their price is $30 off Apple’s MSRP, and it’s the lowest price we’ve seen for AirPods Pro. Available... Read more
Apple’s $779 13″ MacBook Air deal returns to...
Apple has clearance, Certified Refurbished, 2019 13″ MacBook Airs available again starting at $779. Each MacBook features a new outer case, comes with a standard Apple one-year warranty, and is... Read more
$200 13″ MacBook Pro discounts are back at Am...
Amazon has 2020 13″ 2.0GHz MacBook Pros on sale again today for $150-$200 off Apple’s MSRP. Shipping is free. Be sure to purchase the MacBook Pro from Amazon, rather than a third-party seller, and... Read more
Deal Alert! Apple AirPods with Wireless Charg...
Sams Club has Apple AirPods with Wireless Charging Case on sale on their online store for only $149.98 from July 6, 2020 to July 9, 2020. Their price is $50 off Apple’s MSRP, and it’s the lowest... Read more
Xfinity Mobile promo: Apple iPhone XS models...
Take $300 off the purchase of any Apple iPhone XS model at Xfinity Mobile while supplies last. Service plan required: – 64GB iPhone XS: $599.99 save $300 – 256GB iPhone XS: $749.99 save $300 – 512GB... Read more
New July 2020 promo at US Cellular: Switch an...
US Cellular has introduced a new July 2020 deal offering free 64GB Apple iPhone 11 smartphones to customers opening a new line of service. No trade-in required, and discounts are applied via monthly... Read more
Apple offers up to $400 Education discount on...
Apple has launched their Back to School promotion for 2020. They will include one free pair Apple AirPods (with charging case) with the purchase of a MacBook Air, MacBook Pro, iMac, or iMac Pro (Mac... Read more
July 4th Sale: Woot offers wide range of Macs...
Amazon-owned Woot is blowing out a wide range of Apple Macs and iPads for July 4th staring at $279 and ranging up to just over $1000. Models vary from older iPads and 11″ MacBook Airs to some newer... Read more
Apple Pro Display XDR with Nano-Texture Glass...
Abt Electronics has Apple’s new 32″ Pro Display XDR model with the nano-texture glass in stock and on sale today for up to $144 off MSRP. Shipping is free: – Pro Display XDR (nano-texture glass): $... Read more
New 2020 Mac mini on sale for up to $100 off...
Amazon has Apple’s new 2020 Mac minis on sale today for $40-$100 off MSRP with prices starting at $759. Shipping is free: – 2020 4-Core Mac mini: $759 $40 off MSRP – 2020 6-Core Mac mini: $998.99 $... Read more

Jobs Board

Physical Therapist Assistant - *Apple* Hill...
Physical Therapist Assistant - Apple Hill Rehab - Full Time Tracking Code 62519 Job Description General Summary: Under the direct supervision of a licensed Physical Read more
Operating Room Assistant, *Apple* Hill Surg...
Operating Room Assistant, Apple Hill Surgical Center - Full Time, Day Shift, Monday - Saturday availability required Tracking Code 62363 Job Description Operating Read more
Perioperative RN - ( *Apple* Hill Surgical C...
Perioperative RN - ( Apple Hill Surgical Center) Tracking Code 60593 Job Description Monday - Friday - Full Time Days Possible Saturdays General Summary: Under the Read more
Product Manager, *Apple* Commercial Sales -...
Product Manager, Apple Commercial Sales Austin, TX, US Requisition Number:77652 As an Apple Product Manager for the Commercial Sales team at Insight, you Read more
*Apple* Mac Product Engineer - Barclays (Uni...
Apple Mac EngineerWhippany, NJ Support the development and delivery of solutions, products, and capabilities into the Barclays environment working across technical Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.