Slashdot Mirror
Perl 6 Showcase
maraist writes: "Larry Wall's Altanta Linux Showcase Talk on Perl 6 is now available. Highlights: Perl will be interpreted by Perl (syntax can look like any language), variables will be more localized and OO, more support of both low level and high level constructs, and the core will be streamlined."
But why would anyone want to interpret Python in Perl
You're not "interpreting" python in Perl.. You're taking Python Syntax and parsing it into Perl Byte-code. Just like Python can be compiled into Java byte-code or, heaven forbid, Python byte-code.
The idea was that Perl had this great regular expression package (bar none), but it's not actually used _by_ perl. So, they're going to chuck the old yacc-based parser and use raw perl reg-ex's with a rec-descent parser (as opposed to a bottom up yacc parser), so that _any_ syntax could conceivably be used.. More importantly, the parser itself can be dynamically extended. The best part is that each module could use it's own syntax independantly of other modules (scope-based parsing). So I could literraly load in Java source-code or Python source code through a use statement.. Now, that is vapor-ware.. The more realistic result will be that you can load perl 4 or 5 modules without compatibility head-aches. Any going from C# or Python to Perl should not be too troublesome.
Other features that were cool were that the garbage collector was going to be abstracted. Partly to try and avoid the current pitfalls with memoryleaks, and partly so that Perl could be ploped right on top of a Java VM using a Java garbage collector. Though the following wasn't mentioned, what this could give you would be immediate access to most every desktop in the world.. i.e. Write perl code that runs inside an MS Java VM after being pre-compiled into java byte-code with a potential perl-translator layer.
The specifics are all up in the air.. This was just a directions discussion.
-Michael
-Michael
So, what else can Perl 6 do that is new as far as applications go? I assume there is more new functionality.
Well, you can read the transcript or just the summary.
This wasn't an outline of the language.. Larry hasn't even finished reading all the suggestions about what should go into the language.. He's no where near ready to give an outline. Try another 1,2 or 3 years before we start to see stable releases included with Red Hat.
BTW, why doesn't he just use the term 'macro' for that 'great' new capability of looking like other languages? IMHO, if I want to do Perl, I will write Perl.
Well, thats easy.. Because they're NOT macros... That's the beauty of it. Basically you have the abilty to write your own PARSER for perl... OR, extend an existing one.. On the fly.. Basically, it's the equivalent to using Perl's Parser::RecDescent.. Larry even said he wanted a rec-descent parser instead of a bottom up (LR something or other).
The _real_ advantage of this (even if you love perl and Hate python) is that if I'm a mathematician, I can use Unicode to define my own syntax for mathematical operators.. They will have the net effect of being function calls, _but_ the source code will look _exactly_ like it would on a trusty HP calculator in graphical equation mode. Once I or my peers fully define the mathematical superset language for perl, I just use it as is..
The idea was to extend the power of perl's regular expressions by actually using them for once instead of just handing off the job of compilation to a yacc - lexer.
It seems stupid to write Perl with a Java look-a-like because features of the Perl syntax are what makes it good at what it does. For example, just how much spring processing do you do in a Java program? Probably none.
Well, we're not interpreting Java here.. I don't know that we'd be able to even run pure Java code (nor that we'd even want to). But to paraphrase.. If you like the structure that Java syntax provides, you can write a front end parser that restricts your code just like Java.. If you like white-space-sensative code (forcing coding sytle), then you could easily write a python-look-and-feel.
Perl6 will be heavily OO on the inside. Additionally, there will be support for low level datatypes (like arrays of raw int's), so Python, Java and C# should easily fit the mold (these languages came up numerous times).
To answer that last question, however, you would still be using perl regular expressions, not Java's simple c-like string manipulators... You'd just be calling them like you would a normal Java method. The goal for that would be to allow Java programmers to more easily understand the code.. Likewise with C coders (with a C front-end).
Another beauty is that there will be multiple back-end disassemblers. Currently Perl allows you to compile source code to byte code, and you can even take the byte-code and reconstruct source code (though you obviously lose comments and other things). So with multiple back-ends, you could disassemble back into Java or C or Python or Perl5 or even perl6...
-Michael
-Michael
Rob, when are you going to understand that intelligent slashdot readers don't give a shit about Perl?
Sorry for replying to an obvious flame, but I'm opinionated, what can I say. See any one the dozens of posts as to why the world is filled with different types of people and different types of problems.. And how people use different tools to solve problems. Perl DOES solve a certain class of problems exceedingly well. Take what anything bash or most any other shell-script does, for example, and try to do it on a large scale, and you would definately appretiate the power of perl.
If you're not of the class of people that regularly manipulates UNIX environments, then you don't have to care.. But, seeing as how there is a very large group of Linux advocates on slashdot, then logic would suggest that there is a need to manipulate UNIX environments in our midst. Given that, bash, awk, sed, python and yes, even Perl are tools that WE would be interested in. Personally I don't care about the Playstation 2 (I personally hope it dies a painful death), but I have absolutely no problem reading the one paragaph blurb.
Course I also don't hate minorities or deviants with a religious passion.
-Michael
-Michael
Around a year ago I picked up a copy of Learning GNU Emacs by O'Reilly. One part of this excellent book describes using a mini-mode called abbrev-mode, which expands things you type. When I discovered this, I became overzealous and started to create different abbreviations for each major mode.
When I programmed in C++, I would make _loop expand to:
int count;
for ( count = 0; count < x; count++ )
I would then write a _loop macro for Perl which would do the same thing for the Perl minimode. After a short while, I realised where this was going. I started to program in a short form that enabled me to not understand the detailed syntax of the language, and to get by in simple situations with a superficial understanding.
My next experiment was to play around with the idea of a MetaLanguage. It turns out that such a thing may actually be able to output different languages based a generic input language.
It seems that Larry Wall is interested in doing something similar. While there are those who would be against Perl for it's confusing syntax- It never whines about not doing something if it can do anything at all- just try printing a hashref for an example- Perl has done something very interesting over the years.
Perl has shown us how much we are sacrificing by making language syntax simple, unifying and easy to understand. (No, this shouldn't be +1 funny)
Michael Labbe
The language is horrible and unmaintainable.
The same has been said about Pascal, C++, Ada95 and many other very successful languages. The C++ language spec takes up over a foot of space on my bookshelf, and yet C++ is my favorite language for serious programming. Perl, by comparison, is slim.
It's the first language of most new programmers and it shows.
Statistically, that honor belongs to Visual Basic. In college CompSci courses, Java is replacing the C family as the first-taught language.
Most every idiot I seen write perl web apps forget how to write simple function call
That's a problem of lousy programmers, not a lousy language. Don't blame Perl for human stupidity; the latter existed far before the former ever did.
probably because perl does not even supprot that well.
Perl supports functions just fine, thank you very much. Coming from a background of LISP, C, C++, Ada83, Ada95, PROLOG, Java and Fortran-95, I've got to say that Perl doesn't strike me as any more or less sensible than those languages.
Idiots manipulating globals and strings on the stack and such, what crap.
You can manipulate globals just as easily in C as you can with Perl. Again, this is a problem of lousy programmers, not a lousy language.
Interestingly enough, I don't like Perl very much. I can code in it, but it's not something I enjoy. Just because it doesn't float my boat, though, doesn't mean I'm going to baselessly slander it (and make myself look like an idiot in the process).