Re: Re: perlcheat

Perl 6 is a new language.

Err. No. Perl 6 is a new version of the same language: Perl. Just as Perl 5 was. Just as Perl 4 was.

Most of this cheat sheet does not apply to Perl 6.

Au contraire! The vast majority of it is unchanged for Perl 6. See my other node on this topic.

Heck, most of Perl as we know it does not apply to Perl 6.

Just not true. My guess is that about 80% of your existing Perl knowledge will map usefully over to Perl 6.

I think the difference between Perl 5 and 6 will much greater than the difference between C and C++ :)

I very much doubt it. More like the difference between pre-ANSI C++ and post-ANSI C++.

Except, of course, that Perl 6 won't suck. ;-)

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Err. No. Perl 6 is a new version of the same language: Perl. Just as Perl 5 was. Just as Perl 4 was.

I know that's the story. My brain just won't accept it as a fact. Doesn't re-designing something from scratch essentially make it new? Anyhow, please excuse me for spreading wrong information.

Au contraire! The vast majority of it is unchanged for Perl 6.

Array and hash slice and element sigils change, the arrow becomes a nice little dot, parens in constructs like loops are no longer needed for most expressions, the operator precedence table is likely to change, regex metacharacters change as well as regex modifier and predefined classes (or should I say rules?). Many of the special variables change or are reincarnated as att^H^H^Hproperties. That leaves only context (the current list is incomplete too: Perl 5 already has several scalar contexts), sigils (but will there still be globs?), do's and don't's. I wouldn't call that "the vast majority".

Except, of course, that Perl 6 won't suck. ;-)

Of course it won't suck :) And sure, it will still be Perl, a better Perl even. Just not the Perl I know.

Juerd
- http://juerd.nl/
- spamcollector_perlmonks@juerd.nl (do not use).

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I wouldn't call that "the vast majority".

The bits that are the same:

 
 void      $scalar            @array        %hash
 scalar    @array             @array[0, 2]                 
 list      %hash                               
           &sub
                    
                    number, string, reference,       undef

 \     references      
 $@%&  dereference     
 []    anon. arrayref  
 {}    anon. hashref   
 \()   list of refs
                         
                         =          =        perl.plover.com
                         +                   search.cpan.org
 ++ --                   == !=      eq ne         cpan.org
 **                      < > <= >=  lt gt le ge   pm.org
 !   \ u+ u-             <=>        cmp           tpj.com
    !~                                            perldoc.com
 * / % x                 
 + - .                   for    (LIST) { }, 
                         while  ( ) { }, until ( ) { }
 named uops              if     ( ) { } elsif ( ) { } else { }
 < > <= >= lt gt le ge   unless ( ) { } elsif ( ) { } else { }
 == != <=> eq ne cmp     
  
                  
 &&               ^     string begin      
 ||                                      
 ..               +     one or more     
                  *     zero or more   
 = += -= *= etc.  ?     zero or one    
 ,                                  
 list ops         ()    capture          
 not                                                  
 and                                     \s == [\x20\f\t\r\n]
 or xor           |     alternation      \w == [A-Za-z0-9_]
                  \b    word boundary    \d == [0-9] 
                                         \S, \W and \D negate

 use strict;        
 use warnings;      "$foo"           perl.com       
 my $var;           $$variable_name  perlmonks.org  
 open() or die $!;  `$userinput`     use.perl.org   
 use Modules;       /$userinput/     perl.apache.org
                                     parrotcode.org 

 stat      localtime    caller         
  0 dev    0 second     0 package      $_    default variable
  1 ino    1 minute     1 filename     
  2 mode   2 hour       2 line         
  3 nlink  3 day        3 subroutine   
  4 uid    4 month-1    4 hasargs      
  5 gid    5 year-1900  5 wantarray    
  6 rdev   6 weekday    6 evaltext     
  7 size   7 yearday    7 is_require   
  8 atime  8 is_dst     8 hints        
  9 mtime               9 bitmask      @ARGV command line args
 10 ctime  just use                    @INC  include paths
 11 blksz  POSIX::      3..9 only      @_    subroutine args
 12 blcks  strftime!    with EXPR      %ENV  environment
[download]

The bits that differ:

 
                       
                                            @hash{'a', 'b'}
                              $array[0]     $hash{'a'}
                           
           *glob     
                                               glob       

                       $$foo[1]       aka $foo->[1]
     * dereference     $$foo{bar}     aka $foo->{bar}
                       ${$$foo[1]}[2] aka $foo->[1]->[2]
                       ${$$foo[1]}[2] aka $foo->[1][2]
                     
                         
     
 ->                                 .
 

   ~ 
 =~ 
                         
           
 << >>    
         
 
                         for equals foreach (ALWAYS)
 &
 | ^              
                                             /i case insens.
                  $     str. end (before \n) /m line based ^$
    ...                                      /s . includes \n
 ?:                                          /x ign. wh.space
                                             /g global
   =>             {3,7} repeat in range
                                         
                  (?:)  no capture       .  == [^\n]
                  []    character clas 
                 
                  
                  \z    string end 

                    
                                                    
                                                    
                                                     
                                                     
                                                          
 
                                       
                                       
                                       $0    program name
                                       $/    input separator
                                       $\    output separator
                                       $|    autoflush
                                       $!    sys/libcall error
                                       $@    eval error
                                       $$    process ID
                                       $.    line number
[download]

So 153 of the 194 Perl features listed in the cheatsheet (congratulations on packing that much in, by the way!) are the same for Perl 6. That's 79% unchanged. I would call that a "vast majority".

And, yes, I'm counting the for, if, while, etc. syntaxes as being the same. Sure, the parens are optional but that just means you can go on using them exactly as you do now (i.e. no change required).

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