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                          Perl
..                                                                                .




                                                                                      .
                               @yoshiyuki kondo

                          PerlCasual #4 (2011/4/28)




     (@yoshiyuki kondo)           Perl                PerlCasual #4 (2011/4/28)   1 / 44
(          )




(@yoshiyuki kondo)       Perl       PerlCasual #4 (2011/4/28)   2 / 44
(                  )
       Twitter
                 @yoshiyuki_kondo

                 http://www.kondoyoshiyuki.com/




(@yoshiyuki kondo)          Perl                  PerlCasual #4 (2011/4/28)   2 / 44
(                    )
       Twitter
                 @yoshiyuki_kondo

                 http://www.kondoyoshiyuki.com/

                                   Perl
                          Perl




(@yoshiyuki kondo)          Perl                  PerlCasual #4 (2011/4/28)   2 / 44
(                        )
       Twitter
                 @yoshiyuki_kondo

                 http://www.kondoyoshiyuki.com/

                                       Perl
                            Perl

                         C
                         Java




(@yoshiyuki kondo)              Perl              PerlCasual #4 (2011/4/28)   2 / 44
(                        )
       Twitter
                 @yoshiyuki_kondo

                 http://www.kondoyoshiyuki.com/

                                       Perl
                             Perl

                         C
                         Java

                         :



(@yoshiyuki kondo)              Perl              PerlCasual #4 (2011/4/28)   2 / 44
(                           )
       Twitter
                 @yoshiyuki_kondo

                 http://www.kondoyoshiyuki.com/

                                          Perl
                                 Perl

                         C
                         Java

                         :
                             :


(@yoshiyuki kondo)                 Perl              PerlCasual #4 (2011/4/28)   2 / 44
(                           )
       Twitter
                 @yoshiyuki_kondo

                 http://www.kondoyoshiyuki.com/

                                          Perl
                                 Perl

                         C
                         Java

                         :
                             :   Emacs

(@yoshiyuki kondo)                 Perl              PerlCasual #4 (2011/4/28)   2 / 44
(                             )
       Twitter
                 @yoshiyuki_kondo

                 http://www.kondoyoshiyuki.com/

                                            Perl
                                 Perl

                         C
                         Java

                         :
                             :   Emacs
                                        :

(@yoshiyuki kondo)                 Perl                PerlCasual #4 (2011/4/28)   2 / 44
(                           )
       Twitter
                 @yoshiyuki_kondo

                 http://www.kondoyoshiyuki.com/

                                          Perl
                                 Perl

                         C
                         Java

                         :
                             :   Emacs
                                   : T-Code (2                             )

(@yoshiyuki kondo)                 Perl              PerlCasual #4 (2011/4/28)   2 / 44
(@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   3 / 44
(@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   4 / 44
Perl




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   4 / 44
Perl




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   4 / 44
Perl

                      Perl




 (@yoshiyuki kondo)          Perl   PerlCasual #4 (2011/4/28)   4 / 44
(@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   5 / 44
use strict
use warnings




 (@yoshiyuki kondo)   Perl    PerlCasual #4 (2011/4/28)   5 / 44
use strict
 use warnings

#!/usr/bin/perl

use strict;
use warnings;




   (@yoshiyuki kondo)   Perl    PerlCasual #4 (2011/4/28)   5 / 44
use strict




     (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   6 / 44
use strict
    use strict

                                 OK




     (@yoshiyuki kondo)   Perl    PerlCasual #4 (2011/4/28)   6 / 44
use strict
    use strict

                                     OK
    #!/usr/bin/perl
    use strict;
    use warnings;

    $foo = 10;            #   $foo
    my $bar = 2;
    print $foo, "n";     #   $foo
    print $bar, "n";
    print $x, "n";       #   $x




     (@yoshiyuki kondo)       Perl    PerlCasual #4 (2011/4/28)   6 / 44
use strict
    use strict

                                            OK
    #!/usr/bin/perl
    use strict;
    use warnings;

    $foo = 10;            #   $foo
    my $bar = 2;
    print $foo, "n";     #   $foo
    print $bar, "n";
    print $x, "n";       #   $x




    Global symbol "$foo" requires explicit package name at ....



     (@yoshiyuki kondo)       Perl            PerlCasual #4 (2011/4/28)   6 / 44
warnings




    (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   7 / 44
warnings
   use warnings




    (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   7 / 44
warnings
   use warnings


   #!/usr/bin/perl
   use strict;
   use warnings;

   my $foo = "10xxx";
   my $x    = $foo + 5; # $foo
   my $bar;
   print "$barn";      # $bar   undef




    (@yoshiyuki kondo)    Perl       PerlCasual #4 (2011/4/28)   7 / 44
warnings
   use warnings


   #!/usr/bin/perl
   use strict;
   use warnings;

   my $foo = "10xxx";
   my $x    = $foo + 5; # $foo
   my $bar;
   print "$barn";      # $bar                    undef



   Argument "10xxx" isn’t numeric in addition (+) at ....
   Use of uninitialized value $bar in concatenation (.) or string at ....

    (@yoshiyuki kondo)        Perl                     PerlCasual #4 (2011/4/28)   7 / 44
(@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   8 / 44
#!/usr/bin/perl

use strict;
use warnings;




   (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   8 / 44
#!/usr/bin/perl

use strict;
use warnings;




   (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   8 / 44
#!/usr/bin/perl

use strict;
use warnings;




                               !!
   (@yoshiyuki kondo)   Perl        PerlCasual #4 (2011/4/28)   8 / 44
open




                              open




(@yoshiyuki kondo)     Perl      PerlCasual #4 (2011/4/28)   9 / 44
open




                      Perl
open INPUT, "<mydata" or die "Cannot open ’mydata’: $!n";
while (<INPUT>) {
    print $_;
}
close INPUT;




 (@yoshiyuki kondo)            Perl                 PerlCasual #4 (2011/4/28)   10 / 44
open




                      Perl
open INPUT, "<mydata" or die "Cannot open ’mydata’: $!n";
while (<INPUT>) {
    print $_;
}
close INPUT;




 (@yoshiyuki kondo)            Perl                 PerlCasual #4 (2011/4/28)   10 / 44
open




                      Perl
open INPUT, "<mydata" or die "Cannot open ’mydata’: $!n";
while (<INPUT>) {
    print $_;
}
close INPUT;




open my $input, "<", "mydata" or die "Cannot open ’mydata’: $!n";
while (<$input>) {
    print $_;
}
close $input;




 (@yoshiyuki kondo)            Perl                 PerlCasual #4 (2011/4/28)   10 / 44
open




                      Perl
open INPUT, "<mydata" or die "Cannot open ’mydata’: $!n";
while (<INPUT>) {
    print $_;
}
close INPUT;




open my $input, "<", "mydata" or die "Cannot open ’mydata’: $!n";
while (<$input>) {
    print $_;
}
close $input;



            $input

 (@yoshiyuki kondo)            Perl                 PerlCasual #4 (2011/4/28)   10 / 44
open




3                open
open my $input, "<", "mydata"




 (@yoshiyuki kondo)       Perl   PerlCasual #4 (2011/4/28)   11 / 44
open




3                open
open my $input, "<", "mydata"
             1

                                 1                      my




 (@yoshiyuki kondo)       Perl       PerlCasual #4 (2011/4/28)   11 / 44
open




3                open
open my $input, "<", "mydata"
             1

                                 1                      my

             2




 (@yoshiyuki kondo)       Perl       PerlCasual #4 (2011/4/28)   11 / 44
open




3                open
open my $input, "<", "mydata"
             1

                                 1                      my

             2
             3




 (@yoshiyuki kondo)       Perl       PerlCasual #4 (2011/4/28)   11 / 44
open




                      open    1




(@yoshiyuki kondo)     Perl       PerlCasual #4 (2011/4/28)   12 / 44
open




                       open    1



while (<$input>) { ......
my $line = <$input>;




 (@yoshiyuki kondo)     Perl       PerlCasual #4 (2011/4/28)   12 / 44
open




                       open      1



while (<$input>) { ......
my $line = <$input>;


print {$output} "This is a linen";   #
print $output "This is a linen";     #




 (@yoshiyuki kondo)     Perl              PerlCasual #4 (2011/4/28)   12 / 44
open




                       open      1



while (<$input>) { ......
my $line = <$input>;


print {$output} "This is a linen";   #
print $output "This is a linen";     #
print $output, "This is a linen";    #




 (@yoshiyuki kondo)     Perl              PerlCasual #4 (2011/4/28)   12 / 44
open




                       open      1



while (<$input>) { ......
my $line = <$input>;


print {$output} "This is a linen";   #
print $output "This is a linen";     #
print $output, "This is a linen";    #

IO::File
$output->print("This is a line datan");


 (@yoshiyuki kondo)     Perl               PerlCasual #4 (2011/4/28)   12 / 44
(@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   13 / 44
reference




(@yoshiyuki kondo)      Perl     PerlCasual #4 (2011/4/28)   14 / 44
reference


C




(@yoshiyuki kondo)      Perl     PerlCasual #4 (2011/4/28)   14 / 44
reference


C


                                 etc.




(@yoshiyuki kondo)      Perl            PerlCasual #4 (2011/4/28)   14 / 44
C
       $scaler_ref = $scalar;   #




(@yoshiyuki kondo)   Perl            PerlCasual #4 (2011/4/28)   15 / 44
C
       $scaler_ref = $scalar;    #
       $array_ref    = @array;   #




(@yoshiyuki kondo)    Perl            PerlCasual #4 (2011/4/28)   15 / 44
C
       $scaler_ref = $scalar;    #
       $array_ref    = @array;   #
       $hash_ref     = %hash;    #




(@yoshiyuki kondo)    Perl            PerlCasual #4 (2011/4/28)   15 / 44
C
       $scaler_ref = $scalar;       #
       $array_ref    = @array;      #
       $hash_ref     = %hash;       #
       $func_ref     = &function;   #




(@yoshiyuki kondo)    Perl               PerlCasual #4 (2011/4/28)   15 / 44
C
       $scaler_ref = $scalar;       #
       $array_ref    = @array;      #
       $hash_ref     = %hash;       #
       $func_ref     = &function;   #
       $glob_ref     = *STDOUT;     #




(@yoshiyuki kondo)    Perl               PerlCasual #4 (2011/4/28)   15 / 44
C
       $scaler_ref = $scalar;       #
       $array_ref    = @array;      #
       $hash_ref     = %hash;       #
       $func_ref     = &function;   #
       $glob_ref     = *STDOUT;     #




(@yoshiyuki kondo)    Perl               PerlCasual #4 (2011/4/28)   15 / 44
dereference




(@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   16 / 44
dereference

Perl




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   16 / 44
(@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   17 / 44
$sref = $x;




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   17 / 44
$sref = $x;

$a = $$ref;




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   17 / 44
$sref = $x;

$a = $$ref;

my $x = 100;
my $sref = $x; #                               $sref

print "$$sref $xn";         # 100 100
$$sref += 5;
print "$$sref $xn";         # 105 105
 (@yoshiyuki kondo)   Perl               PerlCasual #4 (2011/4/28)   17 / 44
(@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   18 / 44
$array_ref = @array;




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   18 / 44
$array_ref = @array;



@s = @$array_ref;




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   18 / 44
$array_ref = @array;



@s = @$array_ref;

$$array_ref[10] = 10;




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   18 / 44
$array_ref = @array;



@s = @$array_ref;

$$array_ref[10] = 10;
foreach
foreach (@$array_ref) {




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   18 / 44
compute sum:

sub compute_sum {
    my ($aref) = @_; #           $aref
    my $sum = 0;
    foreach (@$aref) { #
        $sum += $_;
    }
    return $sum;
}




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   19 / 44
(@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   20 / 44
$href = %h;




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   20 / 44
$href = %h;



$x = $$href{’a’};




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   20 / 44
$href = %h;



$x = $$href{’a’};
keys
foreach (keys %$href) {




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   20 / 44
(coderef)




(@yoshiyuki kondo)          Perl   PerlCasual #4 (2011/4/28)   21 / 44
(coderef)

$fref = &func;




 (@yoshiyuki kondo)          Perl   PerlCasual #4 (2011/4/28)   21 / 44
(coderef)

$fref = &func;


&$fref($param);




 (@yoshiyuki kondo)          Perl   PerlCasual #4 (2011/4/28)   21 / 44
$aref = @array;
$$aref = 10;
       Not a SCALAR reference at - line 7.




(@yoshiyuki kondo)      Perl                 PerlCasual #4 (2011/4/28)   22 / 44
ref




                                  REF
                                  SCALAR
                                  ARRAY
                                  HASH
                                  CODE
                                  GLOB



      (@yoshiyuki kondo)   Perl            PerlCasual #4 (2011/4/28)   23 / 44
(@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   24 / 44
print




(@yoshiyuki kondo)           Perl   PerlCasual #4 (2011/4/28)   24 / 44
print
                                16
                     CODE(0xbb5b48), HASH(0xbb59f8)




(@yoshiyuki kondo)           Perl             PerlCasual #4 (2011/4/28)   24 / 44
print
                                16
                     CODE(0xbb5b48), HASH(0xbb59f8)
eq




(@yoshiyuki kondo)           Perl             PerlCasual #4 (2011/4/28)   24 / 44
print
                                16
                     CODE(0xbb5b48), HASH(0xbb59f8)
eq




(@yoshiyuki kondo)           Perl             PerlCasual #4 (2011/4/28)   24 / 44
(@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   25 / 44
(@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   25 / 44
${$sref}




(@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   25 / 44
${$sref}

@{&get_array_ref()}




(@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   25 / 44
${$sref}

@{&get_array_ref()}
${$a[2]} $$a[2]
       $$a[2]        ${$a}[2]


(@yoshiyuki kondo)        Perl   PerlCasual #4 (2011/4/28)   25 / 44
${$a[2]}           $$a[2]




    (@yoshiyuki kondo)      Perl   PerlCasual #4 (2011/4/28)   26 / 44
->
     $a->[3]              $$a[3]




     (@yoshiyuki kondo)            Perl   PerlCasual #4 (2011/4/28)   27 / 44
->
     $a->[3] $$a[3]
     $h->{key} $$h{key}




     (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   27 / 44
->
     $a->[3] $$a[3]
     $h->{key} $$h{key}
     $f->($param) &$f($param)




     (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   27 / 44
->
     $a->[3] $$a[3]
     $h->{key} $$h{key}
     $f->($param) &$f($param)

            $a->[3]->[2]




     (@yoshiyuki kondo)    Perl   PerlCasual #4 (2011/4/28)   27 / 44
->
     $a->[3] $$a[3]
     $h->{key} $$h{key}
     $f->($param) &$f($param)

            $a->[3]->[2]
     ->                   [],{} ()          ->
            $a->[3]->[2]       $a->[2][3]




     (@yoshiyuki kondo)        Perl              PerlCasual #4 (2011/4/28)   27 / 44
$a[3][2][5]




(@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   28 / 44
$a[3][2][5]

                     $a[3]->[2]->[5]




(@yoshiyuki kondo)       Perl          PerlCasual #4 (2011/4/28)   28 / 44
$a[3][2][5]

           $a[3]->[2]->[5]
$a->[3][2][5]




(@yoshiyuki kondo)   Perl    PerlCasual #4 (2011/4/28)   28 / 44
$a[2][1]                 $a->[2][1]




    (@yoshiyuki kondo)         Perl   PerlCasual #4 (2011/4/28)   29 / 44
Perl




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   30 / 44
Perl


$a[2][3]




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   30 / 44
Perl


$a[2][3]

$a[2][1] = 100




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   30 / 44
(@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   31 / 44
compute sum
my @tmp_array = (1, 3, 5, 7, 9);
print "Total: ", compute_sum(@tmp_array), "n";

sub compute_sum {
    my ($aref) = @_;
    my $sum = 0;
    foreach (@$aref) {
        $sum += $_;
    }
    return $sum;
}



 (@yoshiyuki kondo)   Perl         PerlCasual #4 (2011/4/28)   32 / 44
compute sum
my @tmp_array = (1, 3, 5, 7, 9);
print "Total: ", compute_sum(@tmp_array), "n";

sub compute_sum {
    my ($aref) = @_;
    my $sum = 0;
    foreach (@$aref) {
        $sum += $_;
    }
    return $sum;
}
                      @tmp array

 (@yoshiyuki kondo)       Perl           PerlCasual #4 (2011/4/28)   32 / 44
Perl                       (anonymous array)

                      []




 (@yoshiyuki kondo)        Perl            PerlCasual #4 (2011/4/28)   33 / 44
Perl                       (anonymous array)

                      []


   )
        5                                               $aref

        $aref = [1, 2, 3, 4, 5]




 (@yoshiyuki kondo)        Perl            PerlCasual #4 (2011/4/28)   33 / 44
Perl                       (anonymous array)

                      []


   )
        5                                               $aref

        $aref = [1, 2, 3, 4, 5]




 (@yoshiyuki kondo)        Perl            PerlCasual #4 (2011/4/28)   33 / 44
compute sum
print "Total: ", compute_sum([1, 3, 5, 7, 9]), "n";




 (@yoshiyuki kondo)    Perl       PerlCasual #4 (2011/4/28)   34 / 44
compute sum
print "Total: ", compute_sum([1, 3, 5, 7, 9]), "n";
              (1, 2, 3)          [1, 2, 3]




 (@yoshiyuki kondo)       Perl       PerlCasual #4 (2011/4/28)   34 / 44
anonymous
hash
                     {}




(@yoshiyuki kondo)        Perl   PerlCasual #4 (2011/4/28)   35 / 44
anonymous
hash
                     {}




  )                              3

$href = {one => 1, two => 2, three => 3};




(@yoshiyuki kondo)        Perl       PerlCasual #4 (2011/4/28)   35 / 44
=>
=>         (thick arrow)          (
Perl p121)




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   36 / 44
=>
=>         (thick arrow)          (
Perl p121)




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   36 / 44
=>
=>         (thick arrow)            (
Perl p121)

        =>                      (
            )




 (@yoshiyuki kondo)   Perl   PerlCasual #4 (2011/4/28)   36 / 44
=>
=>         (thick arrow)                     (
Perl p121)

        =>                               (
            )


        $href = {one => 1, two => 2, three => 3};




 (@yoshiyuki kondo)   Perl            PerlCasual #4 (2011/4/28)   36 / 44
=>
=>         (thick arrow)                     (
Perl p121)

        =>                               (
            )


        $href = {one => 1, two => 2, three => 3};

        $href = {’one’, 1, ’two’, 2, ’three’, 3 };




 (@yoshiyuki kondo)   Perl            PerlCasual #4 (2011/4/28)   36 / 44
=>
=>         (thick arrow)                     (
Perl p121)

        =>                               (
            )


        $href = {one => 1, two => 2, three => 3};

        $href = {’one’, 1, ’two’, 2, ’three’, 3 };


                      =>

 (@yoshiyuki kondo)        Perl       PerlCasual #4 (2011/4/28)   36 / 44
=>
=>         (thick arrow)                        (
Perl p121)

           =>                               (
               )


           $href = {one => 1, two => 2, three => 3};

           $href = {’one’, 1, ’two’, 2, ’three’, 3 };


                         =>
(                                                     )
    (@yoshiyuki kondo)        Perl       PerlCasual #4 (2011/4/28)   36 / 44
(                )

my $userinfo = {         name => $name,
                         uid => $uid,
                         gid => [1, 200, 201, 203],
                         env => {
                               HOME => $ENV{HOME},
                               TERM => "VT100" } };




    (@yoshiyuki kondo)   Perl           PerlCasual #4 (2011/4/28)   37 / 44
Data::Dumper


                                ?




    (@yoshiyuki kondo)   Perl       PerlCasual #4 (2011/4/28)   38 / 44
Data::Dumper


                                          ?
                                HASH(0x116360)




    (@yoshiyuki kondo)   Perl                 PerlCasual #4 (2011/4/28)   38 / 44
Data::Dumper


                                                     ?
                             HASH(0x116360)
                 Data::Dumper
   $VAR1 = {
               ’uid’ => 1001,
               ’env’ => {
                           ’HOME’ => ’/home/cond’,
                           ’TERM’ => ’VT100’
                        },
               ’name’ => ’John’,
               ’gid’ => [
                           1,
                           200,
                           201,
                           203
                        ]
             };

    (@yoshiyuki kondo)           Perl                    PerlCasual #4 (2011/4/28)   38 / 44
(   )




                                    (              )




(@yoshiyuki kondo)           Perl       PerlCasual #4 (2011/4/28)   39 / 44
(   )




Perl                                 anonymous
subroutine




 (@yoshiyuki kondo)           Perl        PerlCasual #4 (2011/4/28)   40 / 44
(   )




Perl                                 anonymous
subroutine
        sub { ..... }




 (@yoshiyuki kondo)           Perl        PerlCasual #4 (2011/4/28)   40 / 44
(   )




Perl                                 anonymous
subroutine
        sub { ..... }




 (@yoshiyuki kondo)           Perl        PerlCasual #4 (2011/4/28)   40 / 44
(   )




Perl                                 anonymous
subroutine
        sub { ..... }


                                           fref
$fref = sub { print "Hello, $_[0]n"; }




 (@yoshiyuki kondo)           Perl        PerlCasual #4 (2011/4/28)   40 / 44
(   )




Perl                                 anonymous
subroutine
        sub { ..... }


                                           fref
$fref = sub { print "Hello, $_[0]n"; }

&$fref("world");




 (@yoshiyuki kondo)           Perl        PerlCasual #4 (2011/4/28)   40 / 44
(   )




Perl                                     anonymous
subroutine
        sub { ..... }


                                               fref
$fref = sub { print "Hello, $_[0]n"; }

&$fref("world");
->                                                             (
                                     )
$fref->("world");

 (@yoshiyuki kondo)           Perl            PerlCasual #4 (2011/4/28)   40 / 44
(       )




                         (closure)      ?

                                 (my    )




(@yoshiyuki kondo)               Perl       PerlCasual #4 (2011/4/28)   41 / 44
(   )



     adder:


sub adder {
    my ($increment) = @_;             #

    return sub {
        my ($x) = @_;
        return $x + $increment;
    }
}

my $add1 = adder(1);               # 1
my $add20 = adder(20);             # 20

print $add1->(10), "n";             # 11
print $add20->(10), "n";            # 30
print $add1->(30), "n";             # 31
      (@yoshiyuki kondo)             Perl   PerlCasual #4 (2011/4/28)   42 / 44
(    )



        make counter:

sub make_counter {
    my ($counter) = @_;                  #

    return sub {             return ++$counter };
}

my $foo = make_counter(0);   #                  0
my $bar = make_counter(100); #                  100

print   $foo->(),        "n";     #   1
print   $bar->(),        "n";     #   101
print   $bar->(),        "n";     #   102
print   $foo->(),        "n";     #   2
print   $bar->(),        "n";     #   103
print   $foo->(),        "n";     #   3

        (@yoshiyuki kondo)              Perl          PerlCasual #4 (2011/4/28)   43 / 44
(   )




(@yoshiyuki kondo)           Perl   PerlCasual #4 (2011/4/28)   44 / 44
(   )




                                     use strict
use warnings




 (@yoshiyuki kondo)           Perl   PerlCasual #4 (2011/4/28)   44 / 44

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Perl中級者への道 (近藤 嘉雪, at PerlCasual #4)

  • 1. . . . Perl .. . . @yoshiyuki kondo PerlCasual #4 (2011/4/28) (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 1 / 44
  • 2. ( ) (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 2 / 44
  • 3. ( ) Twitter @yoshiyuki_kondo http://www.kondoyoshiyuki.com/ (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 2 / 44
  • 4. ( ) Twitter @yoshiyuki_kondo http://www.kondoyoshiyuki.com/ Perl Perl (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 2 / 44
  • 5. ( ) Twitter @yoshiyuki_kondo http://www.kondoyoshiyuki.com/ Perl Perl C Java (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 2 / 44
  • 6. ( ) Twitter @yoshiyuki_kondo http://www.kondoyoshiyuki.com/ Perl Perl C Java : (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 2 / 44
  • 7. ( ) Twitter @yoshiyuki_kondo http://www.kondoyoshiyuki.com/ Perl Perl C Java : : (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 2 / 44
  • 8. ( ) Twitter @yoshiyuki_kondo http://www.kondoyoshiyuki.com/ Perl Perl C Java : : Emacs (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 2 / 44
  • 9. ( ) Twitter @yoshiyuki_kondo http://www.kondoyoshiyuki.com/ Perl Perl C Java : : Emacs : (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 2 / 44
  • 10. ( ) Twitter @yoshiyuki_kondo http://www.kondoyoshiyuki.com/ Perl Perl C Java : : Emacs : T-Code (2 ) (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 2 / 44
  • 11. (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 3 / 44
  • 12. (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 4 / 44
  • 13. Perl (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 4 / 44
  • 14. Perl (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 4 / 44
  • 15. Perl Perl (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 4 / 44
  • 16. (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 5 / 44
  • 17. use strict use warnings (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 5 / 44
  • 18. use strict use warnings #!/usr/bin/perl use strict; use warnings; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 5 / 44
  • 19. use strict (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 6 / 44
  • 20. use strict use strict OK (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 6 / 44
  • 21. use strict use strict OK #!/usr/bin/perl use strict; use warnings; $foo = 10; # $foo my $bar = 2; print $foo, "n"; # $foo print $bar, "n"; print $x, "n"; # $x (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 6 / 44
  • 22. use strict use strict OK #!/usr/bin/perl use strict; use warnings; $foo = 10; # $foo my $bar = 2; print $foo, "n"; # $foo print $bar, "n"; print $x, "n"; # $x Global symbol "$foo" requires explicit package name at .... (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 6 / 44
  • 23. warnings (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 7 / 44
  • 24. warnings use warnings (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 7 / 44
  • 25. warnings use warnings #!/usr/bin/perl use strict; use warnings; my $foo = "10xxx"; my $x = $foo + 5; # $foo my $bar; print "$barn"; # $bar undef (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 7 / 44
  • 26. warnings use warnings #!/usr/bin/perl use strict; use warnings; my $foo = "10xxx"; my $x = $foo + 5; # $foo my $bar; print "$barn"; # $bar undef Argument "10xxx" isn’t numeric in addition (+) at .... Use of uninitialized value $bar in concatenation (.) or string at .... (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 7 / 44
  • 27. (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 8 / 44
  • 28. #!/usr/bin/perl use strict; use warnings; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 8 / 44
  • 29. #!/usr/bin/perl use strict; use warnings; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 8 / 44
  • 30. #!/usr/bin/perl use strict; use warnings; !! (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 8 / 44
  • 31. open open (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 9 / 44
  • 32. open Perl open INPUT, "<mydata" or die "Cannot open ’mydata’: $!n"; while (<INPUT>) { print $_; } close INPUT; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 10 / 44
  • 33. open Perl open INPUT, "<mydata" or die "Cannot open ’mydata’: $!n"; while (<INPUT>) { print $_; } close INPUT; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 10 / 44
  • 34. open Perl open INPUT, "<mydata" or die "Cannot open ’mydata’: $!n"; while (<INPUT>) { print $_; } close INPUT; open my $input, "<", "mydata" or die "Cannot open ’mydata’: $!n"; while (<$input>) { print $_; } close $input; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 10 / 44
  • 35. open Perl open INPUT, "<mydata" or die "Cannot open ’mydata’: $!n"; while (<INPUT>) { print $_; } close INPUT; open my $input, "<", "mydata" or die "Cannot open ’mydata’: $!n"; while (<$input>) { print $_; } close $input; $input (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 10 / 44
  • 36. open 3 open open my $input, "<", "mydata" (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 11 / 44
  • 37. open 3 open open my $input, "<", "mydata" 1 1 my (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 11 / 44
  • 38. open 3 open open my $input, "<", "mydata" 1 1 my 2 (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 11 / 44
  • 39. open 3 open open my $input, "<", "mydata" 1 1 my 2 3 (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 11 / 44
  • 40. open open 1 (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 12 / 44
  • 41. open open 1 while (<$input>) { ...... my $line = <$input>; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 12 / 44
  • 42. open open 1 while (<$input>) { ...... my $line = <$input>; print {$output} "This is a linen"; # print $output "This is a linen"; # (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 12 / 44
  • 43. open open 1 while (<$input>) { ...... my $line = <$input>; print {$output} "This is a linen"; # print $output "This is a linen"; # print $output, "This is a linen"; # (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 12 / 44
  • 44. open open 1 while (<$input>) { ...... my $line = <$input>; print {$output} "This is a linen"; # print $output "This is a linen"; # print $output, "This is a linen"; # IO::File $output->print("This is a line datan"); (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 12 / 44
  • 45. (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 13 / 44
  • 46. reference (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 14 / 44
  • 47. reference C (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 14 / 44
  • 48. reference C etc. (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 14 / 44
  • 49. C $scaler_ref = $scalar; # (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 15 / 44
  • 50. C $scaler_ref = $scalar; # $array_ref = @array; # (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 15 / 44
  • 51. C $scaler_ref = $scalar; # $array_ref = @array; # $hash_ref = %hash; # (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 15 / 44
  • 52. C $scaler_ref = $scalar; # $array_ref = @array; # $hash_ref = %hash; # $func_ref = &function; # (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 15 / 44
  • 53. C $scaler_ref = $scalar; # $array_ref = @array; # $hash_ref = %hash; # $func_ref = &function; # $glob_ref = *STDOUT; # (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 15 / 44
  • 54. C $scaler_ref = $scalar; # $array_ref = @array; # $hash_ref = %hash; # $func_ref = &function; # $glob_ref = *STDOUT; # (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 15 / 44
  • 55. dereference (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 16 / 44
  • 56. dereference Perl (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 16 / 44
  • 57. (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 17 / 44
  • 58. $sref = $x; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 17 / 44
  • 59. $sref = $x; $a = $$ref; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 17 / 44
  • 60. $sref = $x; $a = $$ref; my $x = 100; my $sref = $x; # $sref print "$$sref $xn"; # 100 100 $$sref += 5; print "$$sref $xn"; # 105 105 (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 17 / 44
  • 61. (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 18 / 44
  • 62. $array_ref = @array; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 18 / 44
  • 63. $array_ref = @array; @s = @$array_ref; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 18 / 44
  • 64. $array_ref = @array; @s = @$array_ref; $$array_ref[10] = 10; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 18 / 44
  • 65. $array_ref = @array; @s = @$array_ref; $$array_ref[10] = 10; foreach foreach (@$array_ref) { (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 18 / 44
  • 66. compute sum: sub compute_sum { my ($aref) = @_; # $aref my $sum = 0; foreach (@$aref) { # $sum += $_; } return $sum; } (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 19 / 44
  • 67. (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 20 / 44
  • 68. $href = %h; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 20 / 44
  • 69. $href = %h; $x = $$href{’a’}; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 20 / 44
  • 70. $href = %h; $x = $$href{’a’}; keys foreach (keys %$href) { (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 20 / 44
  • 71. (coderef) (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 21 / 44
  • 72. (coderef) $fref = &func; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 21 / 44
  • 73. (coderef) $fref = &func; &$fref($param); (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 21 / 44
  • 74. $aref = @array; $$aref = 10; Not a SCALAR reference at - line 7. (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 22 / 44
  • 75. ref REF SCALAR ARRAY HASH CODE GLOB (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 23 / 44
  • 76. (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 24 / 44
  • 77. print (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 24 / 44
  • 78. print 16 CODE(0xbb5b48), HASH(0xbb59f8) (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 24 / 44
  • 79. print 16 CODE(0xbb5b48), HASH(0xbb59f8) eq (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 24 / 44
  • 80. print 16 CODE(0xbb5b48), HASH(0xbb59f8) eq (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 24 / 44
  • 81. (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 25 / 44
  • 82. (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 25 / 44
  • 83. ${$sref} (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 25 / 44
  • 84. ${$sref} @{&get_array_ref()} (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 25 / 44
  • 85. ${$sref} @{&get_array_ref()} ${$a[2]} $$a[2] $$a[2] ${$a}[2] (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 25 / 44
  • 86. ${$a[2]} $$a[2] (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 26 / 44
  • 87. -> $a->[3] $$a[3] (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 27 / 44
  • 88. -> $a->[3] $$a[3] $h->{key} $$h{key} (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 27 / 44
  • 89. -> $a->[3] $$a[3] $h->{key} $$h{key} $f->($param) &$f($param) (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 27 / 44
  • 90. -> $a->[3] $$a[3] $h->{key} $$h{key} $f->($param) &$f($param) $a->[3]->[2] (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 27 / 44
  • 91. -> $a->[3] $$a[3] $h->{key} $$h{key} $f->($param) &$f($param) $a->[3]->[2] -> [],{} () -> $a->[3]->[2] $a->[2][3] (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 27 / 44
  • 92. $a[3][2][5] (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 28 / 44
  • 93. $a[3][2][5] $a[3]->[2]->[5] (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 28 / 44
  • 94. $a[3][2][5] $a[3]->[2]->[5] $a->[3][2][5] (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 28 / 44
  • 95. $a[2][1] $a->[2][1] (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 29 / 44
  • 96. Perl (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 30 / 44
  • 97. Perl $a[2][3] (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 30 / 44
  • 98. Perl $a[2][3] $a[2][1] = 100 (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 30 / 44
  • 99. (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 31 / 44
  • 100. compute sum my @tmp_array = (1, 3, 5, 7, 9); print "Total: ", compute_sum(@tmp_array), "n"; sub compute_sum { my ($aref) = @_; my $sum = 0; foreach (@$aref) { $sum += $_; } return $sum; } (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 32 / 44
  • 101. compute sum my @tmp_array = (1, 3, 5, 7, 9); print "Total: ", compute_sum(@tmp_array), "n"; sub compute_sum { my ($aref) = @_; my $sum = 0; foreach (@$aref) { $sum += $_; } return $sum; } @tmp array (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 32 / 44
  • 102. Perl (anonymous array) [] (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 33 / 44
  • 103. Perl (anonymous array) [] ) 5 $aref $aref = [1, 2, 3, 4, 5] (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 33 / 44
  • 104. Perl (anonymous array) [] ) 5 $aref $aref = [1, 2, 3, 4, 5] (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 33 / 44
  • 105. compute sum print "Total: ", compute_sum([1, 3, 5, 7, 9]), "n"; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 34 / 44
  • 106. compute sum print "Total: ", compute_sum([1, 3, 5, 7, 9]), "n"; (1, 2, 3) [1, 2, 3] (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 34 / 44
  • 107. anonymous hash {} (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 35 / 44
  • 108. anonymous hash {} ) 3 $href = {one => 1, two => 2, three => 3}; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 35 / 44
  • 109. => => (thick arrow) ( Perl p121) (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 36 / 44
  • 110. => => (thick arrow) ( Perl p121) (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 36 / 44
  • 111. => => (thick arrow) ( Perl p121) => ( ) (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 36 / 44
  • 112. => => (thick arrow) ( Perl p121) => ( ) $href = {one => 1, two => 2, three => 3}; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 36 / 44
  • 113. => => (thick arrow) ( Perl p121) => ( ) $href = {one => 1, two => 2, three => 3}; $href = {’one’, 1, ’two’, 2, ’three’, 3 }; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 36 / 44
  • 114. => => (thick arrow) ( Perl p121) => ( ) $href = {one => 1, two => 2, three => 3}; $href = {’one’, 1, ’two’, 2, ’three’, 3 }; => (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 36 / 44
  • 115. => => (thick arrow) ( Perl p121) => ( ) $href = {one => 1, two => 2, three => 3}; $href = {’one’, 1, ’two’, 2, ’three’, 3 }; => ( ) (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 36 / 44
  • 116. ( ) my $userinfo = { name => $name, uid => $uid, gid => [1, 200, 201, 203], env => { HOME => $ENV{HOME}, TERM => "VT100" } }; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 37 / 44
  • 117. Data::Dumper ? (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 38 / 44
  • 118. Data::Dumper ? HASH(0x116360) (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 38 / 44
  • 119. Data::Dumper ? HASH(0x116360) Data::Dumper $VAR1 = { ’uid’ => 1001, ’env’ => { ’HOME’ => ’/home/cond’, ’TERM’ => ’VT100’ }, ’name’ => ’John’, ’gid’ => [ 1, 200, 201, 203 ] }; (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 38 / 44
  • 120. ( ) ( ) (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 39 / 44
  • 121. ( ) Perl anonymous subroutine (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 40 / 44
  • 122. ( ) Perl anonymous subroutine sub { ..... } (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 40 / 44
  • 123. ( ) Perl anonymous subroutine sub { ..... } (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 40 / 44
  • 124. ( ) Perl anonymous subroutine sub { ..... } fref $fref = sub { print "Hello, $_[0]n"; } (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 40 / 44
  • 125. ( ) Perl anonymous subroutine sub { ..... } fref $fref = sub { print "Hello, $_[0]n"; } &$fref("world"); (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 40 / 44
  • 126. ( ) Perl anonymous subroutine sub { ..... } fref $fref = sub { print "Hello, $_[0]n"; } &$fref("world"); -> ( ) $fref->("world"); (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 40 / 44
  • 127. ( ) (closure) ? (my ) (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 41 / 44
  • 128. ( ) adder: sub adder { my ($increment) = @_; # return sub { my ($x) = @_; return $x + $increment; } } my $add1 = adder(1); # 1 my $add20 = adder(20); # 20 print $add1->(10), "n"; # 11 print $add20->(10), "n"; # 30 print $add1->(30), "n"; # 31 (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 42 / 44
  • 129. ( ) make counter: sub make_counter { my ($counter) = @_; # return sub { return ++$counter }; } my $foo = make_counter(0); # 0 my $bar = make_counter(100); # 100 print $foo->(), "n"; # 1 print $bar->(), "n"; # 101 print $bar->(), "n"; # 102 print $foo->(), "n"; # 2 print $bar->(), "n"; # 103 print $foo->(), "n"; # 3 (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 43 / 44
  • 130. ( ) (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 44 / 44
  • 131. ( ) use strict use warnings (@yoshiyuki kondo) Perl PerlCasual #4 (2011/4/28) 44 / 44