On Perl 6

And then I visited [link|http://www.msnbc.msn.com/id/6205119/|http://www.msnbc.msn.com/id/6205119/] and Galeon locked up on me. Gah.

So you're getting the really short version.

Some things are just plain different. For instance method calls are . rather than ->, you write %foo{$bar} rather than $foo{$bar}, a few operators changed, etc. Most of the changes make the language less surprising for people who are learning it.

Perl regular expressions now have facilities for flexibly capturing lots of information about the match. You also can build them up from small pieces. This has all been carefully designed so that you can write something that looks a lot like a BNF grammar and you'll get a regular expression that actually parses that grammar. (It is only a recursive descent parser though.) These complex regular expressions are known as (surprise, surprise) grammars.

Perl 6's grammar will be a Perl 6 grammar. This grammar will be available to play with, and can be overridden on the fly (this is the upside of a recursive descent parser - you can play these games). This is expected to replace the games that (some) people play today with source filters.

There are many small improvements. For instance:

\n# multi-way comparisons now work\nif (1 < $x < 10) {\n  ...\n}\n\n# Sometimes you don't need parens where you once did.\nif 1 < $x < 10 {\n  ...\n}\n\n# I used it, but didn't point out that this is the\n# "TBD" operator.  It is legal Perl but throws an\n# exception if it executes.\n...\n\n# The print here syntax has some new tricks.\n       print <<EOT;\n           And we write some text here  using the\n         "print here" syntax.  Note that leading\n         whitespace will be stripped to the  EOT\n         marker, letting us maintain code indentation\n         but easily output a block of text that isn't\n         indented.\n         EOT\n\n# Pipelines let us write code top to bottom where\n# previously it was bottom to top.  Compare a\n# Schwartzian transform in Perl 5:\nmy @shortest_first                     # 5\n  = map { $_->[0] }                    # 4\n    sort { $a->[1] <=> $b->[1] }       # 3\n    map { [ $_, $_->height ] }         # 2\n    @animals;                          # 1\n# with one in Perl 6:\n@animals                               # 1\n  ==> map { [ $_, .height ] }          # 2\n  ==> sort { $^a[1] <=> $^b[1] }       # 3\n  ==> map { $_[0] }                    # 4\n  ==> my @shortest_first;              # 5\n\n# Junctions let you write code like this:\nif any(@these) > all(@those) {\n  print "These have the largest element\\n";\n}\n

Perl 6 has a much richer object system. It adds lots of goodies for those who like functional programming. Named arguments to functions. And a swarm of smaller improvements.

Cheers,
Ben

Post #178,383 by pwhysall 10/8/04 1:53:55 AM Reply	On Perl 6 Would you mind posting a one-page simpleton's summary of what's new and shiny and different in Perl 6? I use Perl as a kind of Turbo Awk On Steroids, so I imagine that it'd have to change fairly drastically for me to notice much. Peter [link\|http://www.debian.org\|Shill For Hire] [link\|http://www.kuro5hin.org\|There is no K5 Cabal] [link\|http://guildenstern.dyndns.org\|Blog]
Post #178,409 by Yendor 10/8/04 8:37:56 AM Reply	Re: On Perl 6 OK, so it ain't one page. It ain't anywhere CLOSE to one page. Matter of fact, it's the closest I can find to The Whole Shebang: [link\|http://dev.perl.org/perl6/apocalypse/\|Larry Wall's Apocalypses]. -YendorMike "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." - Benjamin Franklin, 1759 Historical Review of Pennsylvania
Post #178,462 by ben_tilly 10/8/04 12:54:37 PM Reply	I had a nice response to this typed up And then I visited [link\|http://www.msnbc.msn.com/id/6205119/\|http://www.msnbc.msn.com/id/6205119/] and Galeon locked up on me. Gah. So you're getting the really short version. Some things are just plain different. For instance method calls are . rather than ->, you write %foo{$bar} rather than $foo{$bar}, a few operators changed, etc. Most of the changes make the language less surprising for people who are learning it. Perl regular expressions now have facilities for flexibly capturing lots of information about the match. You also can build them up from small pieces. This has all been carefully designed so that you can write something that looks a lot like a BNF grammar and you'll get a regular expression that actually parses that grammar. (It is only a recursive descent parser though.) These complex regular expressions are known as (surprise, surprise) grammars. Perl 6's grammar will be a Perl 6 grammar. This grammar will be available to play with, and can be overridden on the fly (this is the upside of a recursive descent parser - you can play these games). This is expected to replace the games that (some) people play today with source filters. There are many small improvements. For instance: \n# multi-way comparisons now work\nif (1 < $x < 10) {\n ...\n}\n\n# Sometimes you don't need parens where you once did.\nif 1 < $x < 10 {\n ...\n}\n\n# I used it, but didn't point out that this is the\n# "TBD" operator. It is legal Perl but throws an\n# exception if it executes.\n...\n\n# The print here syntax has some new tricks.\n print <<EOT;\n And we write some text here using the\n "print here" syntax. Note that leading\n whitespace will be stripped to the EOT\n marker, letting us maintain code indentation\n but easily output a block of text that isn't\n indented.\n EOT\n\n# Pipelines let us write code top to bottom where\n# previously it was bottom to top. Compare a\n# Schwartzian transform in Perl 5:\nmy @shortest_first # 5\n = map { $_->[0] } # 4\n sort { $a->[1] <=> $b->[1] } # 3\n map { [ $_, $_->height ] } # 2\n @animals; # 1\n# with one in Perl 6:\n@animals # 1\n ==> map { [ $_, .height ] } # 2\n ==> sort { $^a[1] <=> $^b[1] } # 3\n ==> map { $_[0] } # 4\n ==> my @shortest_first; # 5\n\n# Junctions let you write code like this:\nif any(@these) > all(@those) {\n print "These have the largest element\\n";\n}\n Perl 6 has a much richer object system. It adds lots of goodies for those who like functional programming. Named arguments to functions. And a swarm of smaller improvements. Cheers, Ben I have come to believe that idealism without discipline is a quick road to disaster, while discipline without idealism is pointless. -- Aaron Ward (my brother)
Post #178,588 by pwhysall 10/9/04 2:53:04 AM Reply	Many thanks for that It was the really short version that I wanted :-) [Obsequious note: you're getting (noticeably, over the past 18 months or so) very good at this sort of thing - fawn] Peter [link\|http://www.debian.org\|Shill For Hire] [link\|http://www.kuro5hin.org\|There is no K5 Cabal] [link\|http://guildenstern.dyndns.org\|Blog]

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