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


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:

for ($i=$lo; $i<$hi; $i++) {
  if ($xyz[$i] >= 0) {
    $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 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

Perl is served by two main web sites: and 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 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, 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

Facility 47 (Games)
Facility 47 1.0.1 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0.1 (iTunes) Description: You wake up alone and freezing in an icy cell. You try the cell door but it’s locked, it seems that you are stuck with no... | Read more »
The best Photoshop alternative on iPad
Instagram and Lightroom are great and all, but sometimes people need to get extra creative with their image editing.Like, Photoshop creative. If you're one of these people, take a look at our pick for the best mobile Photoshop experience on iPad... | Read more »
The Walking Dead: No Man’s Land guide -...
A new update for The Walking Dead: No Man’s Land was released last week, making it the perfect time for you to head back to your base and take out some walkers. Here’s the lowdown on what’s new to the game, and how to take advantage. [Read more] | Read more »
Goat Rider guide - Tips and tricks to st...
We've all been there. One second, we're riding high on a crazed goat, and the next, we've been tossed off it like someone who's no good at goat ridin'. [Read more] | Read more »
Real Boxing 2 CREED: How to become a gre...
Just in time for Rocky fans who can’t wait to see CREED, the latest movie, we have the official tie-in game,Real Boxing 2 CREED. It builds on the success of its predecessor and there’s lots to take in so we at 148apps thought we’d run you through... | Read more »
CoinOp Heroes 2 guide - How to build an...
CoinOp Heroes 2 justlaunched and, like all clickers, it's dangerously addictive stuff. You have to furiously tap your screen to defeat wave after wave of foes and earn an insane amount of cash to spend on character upgrades and an army of minions... | Read more »
Dr. Panda Firefighters (Education)
Dr. Panda Firefighters 1.0.1 Device: iOS Universal Category: Education Price: $2.99, Version: 1.0.1 (iTunes) Description: FIGHT FIRES AND SAVE THE DAY!Work together with Dr. Panda and his firefighting team to rescue his trapped... | Read more »
Puddle + (Games)
Puddle + 1.0 Device: iOS iPhone Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Puddle is back in a new "+" edition featuring enhanced graphics, new videos and Apple TV support ! No IAP and No Ads. Dive into Puddle... | Read more »
Football Manager Mobile 2016 (Games)
Football Manager Mobile 2016 7.0.0 Device: iOS Universal Category: Games Price: $8.99, Version: 7.0.0 (iTunes) Description: Football Manager Mobile 2016 is designed to be played on the move and is the quickest way to manage your... | Read more »
Kill Shot Bravo guide - How to become an...
Kill Shot Bravo is a disturbing amount of fun. No matter how many times I play a game that encourages me to snipe people in the head, I feel a little uneasy at how satisfying it is. Here are some useful tips to get you started on your path to... | Read more »

Price Scanner via

Adorama Black Friday deals: Up to $400 off Ma...
Adorama has released their Black Friday deals for 2015. Save up to $400 on MacBook Pros, $200 on MacBooks and MacBook Airs, and $270 on iMacs. Use code RYBFDEAL during checkout to see these prices.... Read more
B&H Photo Deals: $200 off 12-inch 1.2GHz...
In addition to the B&H Photo Black Friday week sales we posted yesterday, B&H has lowered their price on two products to $200 off MSRP: - 12″ 1.2GHz Gray Retina MacBook: $1399 save $200 - 13... Read more
Best Buy Early Access: Today only, Up to $125...
Best Buy has iPad Air 2s on sale for up to $125 off MSRP and Apple Watch models on sale on their online store for up to $100 off MSRP with special codes through midnight CT tonight. Choose free... Read more
UPPERCASE DESIGNS Premium Ultra Thin Keyboard...
UPPERCASE Designs today announced its new Premium Ultra Thin Keyboard Protector and its Palm Rest Protector Set for the 12-inch MacBook. The accessories provide durable protection for the 12-inch... Read more
Al Jazeera Launches New iOS And Android Mobil...
Doha, Qatar based Al Jazeera has launched new mobile and tablet apps on the iOS and Android systems bringing the latest Al Jazeera news and programmes live together with on-demand personalisation.... Read more
B&H Photo Holiday Sale: Up to $250 off Ma...
B&H Photo has all new Macs on sale for up to $500 off MSRP as part of their Holiday sale including free shipping plus NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $1799 $200 off - 15″ 2.... Read more
Free Aura ‘Ultimate’ Mac App For Gmail Update...
Miami, Florida based Crosscoded has announced Aura 1.2.0, an update to the Mac app for Gmail. Aura mixes the power of a native client with the flexibility of the Gmail web app with support for up to... Read more
Apple Will Edge Closer to Samsung in Smartpho...
Total smartphone shipments for 2015 are projected to decline by 9.7% to 1.286 billion units, according to the latest report from global market research firm TrendForce. Though Chinese vendors have... Read more
Sidefari – Split Screen Multitasking In Safar...
Francisco Cantu’s Sidefari is a simple web browser designed to act as a companion to Safari on the iPad. With multitasking in iOS 9, Sidefari uses the new Safari View Controller to show an extra... Read more
12-inch MacBooks in stock for up to $120 off,...
Adorama has 12″ Retina MacBooks in stock for up to $120 off MSRP including free shipping plus NY & NJ sales tax only. For a limited time, Adorama will include a free Apple USB-C to USB Adapter,... Read more

Jobs Board

Merchant Operations Manager: *Apple* Pay -...
Changing the world is all in a day's work at Apple . If you love innovation, here's your chance to make a career of it. You'll work hard. But the job comes with more than Read more
*Apple* Pay QA Manager - Apple Inc. (United...
Changing the world is all in a day's work at Apple . If you love innovation, here's your chance to make a career of it. You'll work hard. But the job comes with more than Read more
Sr Software Engineer *Apple* Pay - Apple In...
Changing the world is all in a day's work at Apple . If you love innovation, here's your chance to make a career of it. You'll work hard. But the job comes with more than Read more
Hardware Systems Architect - *Apple* Watch...
# Hardware Systems Architect - Apple Watch Job Number: 38449977 Santa Clara Valley, Califo ia, United States Posted: Apr. 16, 2015 Weekly Hours: **Job Summary** The Read more
Software Engineer, *Apple* Watch - Apple (U...
# Software Engineer, Apple Watch Job Number: 38181776 Santa Clara Valley, Califo ia, United States Posted: Nov. 2, 2015 Weekly Hours: 40.00 **Job Summary** The Apple Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.