Perl 2, released in , featured a better regular expression engine. Perl 3, released in , added support for binary data streams. Originally the only documentation for Perl was a single increasingly lengthy man page. In , Programming Perl known to many Perl programmers as the "Camel Book" because of its cover was published and became the de facto reference for the language. At the same time, the Perl version number was bumped to 4—not to mark a major change in the language but to identify the version that was documented by the book.
Perl 4 went through a series of maintenance releases, culminating in Perl 4. At that point, Wall abandoned Perl 4 to begin work on Perl 5.
Initial design of Perl 5 continued into The perl5-porters mailing list was established in May to coordinate work on porting Perl 5 to different platforms. It remains the primary forum for development, maintenance, and porting of Perl 5.
Perl 5. It was a nearly complete rewrite of the interpreter, and it added many new features to the language, including objects, references, lexical my variables, and modules.
Importantly, modules provided a mechanism for extending the language without modifying the interpreter. This allowed the core interpreter to stabilize, even as it enabled ordinary Perl programmers to add new language features. Perl 5 has been in active development since then. This allowed module authors to make subroutines that behaved like Perl builtins. One of the most important events in Perl 5 history took place outside of the language proper and was a consequence of its module support.
As of January , it carries over 19, modules by more than 8, authors. Another significant development was the inclusion of the CGI. The year saw the release of Perl 5. This release contained some very significant changes that included such additions as bit support, unicodes, support of files that were over 2Gb and the Perl keyword. During the development of Perl 5.
Later in the year Wall himself put out a notice asking for suggestions in relation to a new Perl version. He specifically aimed this question at the Perl community. The feedback was overwhelming with over comment requests, all of which were used to push the direction of the new Perl program, soon to be known as Perl 6. With Perl 6 underway, saw Apocalypses coming into development, specifically to link in with Perl 6. These were a sequence of documents that was to summarize all the requests that the Perl community had made, as well as to show off the new Perl design and release this next level of Perl software.
Just after this, Perl 5. Even by , the Perl 5. From this point on, the Perl 5 program continued to improve and saw even faster turnarounds with new releases every May. While maybe not sitting at the top of the programming game, it is utilized throughout the web and maintains a strong online presence. History of Perl. History of Perl History of Perl. History of Perl The programming language Perl has been around for a long time. Larry wall.
In this model, the entire Perl interpreter gets cloned and runs in a separate thread. What this means is that not only can you have two interpreters in separate threads that have a common ancestry, you can have completely separate and independent interpreters inside the same process.
The usual provisos apply: your program may not be any faster or smaller than an uncompiled version. Either an upgrade or a downgrade will fix it. Even-numbered minor versions, such as 5.
Together with this, a new method of specifying strings has been created - a literal such as v5. This allows one to compare version numbers using the string comparison operators, and provides a more readable way of writing long Unicode literals; the string above can also be specified as. This is ideal for any number of things which are specified in such a format, such as IP addresses:. I reject death. I will stay away from trucks today. You can also choose to escalate any categories of warning into a fatal error.
As for when , the pragma is lexically scoped, so you can switch it on and off as you wish:. From the department of bizarre syntax, subroutines can now be legal lvalues; that means they can be assigned to. I do occasionally worry about that. Perl keeps track of when values are in use and when they can be taken out of commission by counting the number of references that remain to them. The problem with this was that if you had a variable that was a reference to itself, like this:.
What you can now do is weaken a reference; this means that while it is still a valid reference, it does not add to the reference count. This also means you can keep a spare copy of a variable or an object but not interfere with its lifespan. To take advantage of this, you need to install the WeakRef package from CPAN, and read the further documentation there. The Portable Operating Systems Extension POSIX standards documents define a set of named character classes: the class [:upper:] , for example, matches an upper-case character.
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