postfix dereference 徹底攻略 / effective postfix dereference

Gotanda.pm #16

Transcript

1. postfix dereference
   పఈ߈ུ
   @mackee_w a.k.a macopy
   Gotanda.pm #16
   

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2. ୭ˠ
   • twitter: @mackee_w
   • GitHub: mackee
   • kuiperbelt/kuiperbelt : WebSocketศར܅
   • ࠷ۙPerl Hackers Hubʹςετͱ͔ͷهࣄΛॻ
   ͍ͨ
   

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3. postfix
   dereference
   ͬͯԿ
   

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4. postfix dereference
   $hashref->%*
   $arrayref->@*
   

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5. postfix dereference
   $hashref->%*
   $arrayref->@*
   

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6. postfix dereference
   $hashref->%*
   $arrayref->@*
   

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7. ղઆ
   

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8. postfix dereference
   %{$hashref}
   ||
   $hashref->%*
   

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9. postfix dereference
   @{$arrayref}
   ||
   $arrayref->@*
   

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10. postfix
    ɹ= έπʹͭ͘
    dereference
    ɹ= σϦϑΝϨϯε
    ུ: postderef
    

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11. ֗ͷ੠
    
    
    ಡΊͳ͍ ͜Ε͸ศརʂ
    

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12. ϝϦο
    τ
    

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13. ϝϦοτ
    • ߦͬͯʙฦͬͯͬͯͳΒͳ͍
    %{$aaa->{bbb}}
    $aaa->{bbb}->%*
    1 2 3 4
    5 6 7
    1 2 3 4 5 6
    

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14. σϝϦοτ
    

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15. ……ͳΜͰ
    ه߸૿΍ͪ͠Όͬͨͷʁ
    

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16. ͓٬༷ɺ
    ه߸͸૿΍͓ͯ͠Γ·ͤΜɺ
    ه߸ͷ૊Έ߹ΘͤΛ૿΍ͨ͠
    ͚ͩͳͷͰ͢……
    

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17. ૊Έ߹Θͤ……
    

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18. ୭͕
    *
    ͚ͩͩͱݴͬͨ
    

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19. hash slicing
    my $hashref =
    { k1 => "v1", k2 => "v2", k3 => "v3" };
    # ී௨ͷσϦϑΝϨϯε͔ΒͷϋογϡεϥΠε
    my ($v1, $v3) = @{$hashref}{qw/k1 k3/};
    # postderefͰϋογϡεϥΠε
    my ($v1, $v3) = $hashref->@{qw/k1 k3/};
    

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20. ࣮࣭JSͷobject
    destructuringͰ͸ʁʁʁ
    ※ӈลʹ΋ॻ͔ͳ͍ͱ͍͚ͳ͍ͷͰҧ͍·͢
    https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment
    

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21. ·ͱΊ
    • ʢ໨ͱख͕֮͑Ε͹ʣศར
    • *͚ͩͰ͸ͳ͍ɻΉ͠ΖͦΕҎ֎͕ศར
    • v5.24͔Βexperimental֎Εͨɻ࢖͑·
    ͢ʂʂʂʂ
    • ࠓճͷίʔυ͸શ෦use v5.24.0;ͯ͠·͢
    

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22. http://perldoc.jp/docs/perl/5.24.0/perl5240delta.pod
    

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23. postderef_qqͬͯͳʹ
    

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24. postderef_qq
    my $hashref =
    { k1 => “v1",
    k2 => "v2",
    k3 => "v3" };
    print "[$hashref->@{qw/k1 k3/}]\n";
    # => [v1 v3]
    

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25. ͳΔ΄Ͳͳʁ
    

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26. csvΈ͍ͨʹग़ͨ͠Γ
    my @columns = qw/c1 c2 c3/;
    my $data = [
    { c1 => "aa", c2 => "bb", c3 => "cc" },
    { c1 => "dd", c2 => "ee", c3 => "ff" },
    { c1 => "gg", c2 => "hh", c3 => "ii" },
    ];
    $" = ",";
    print "@columns\n";
    print "$_->@{@columns}\n" for @$data;
    

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27. csvΈ͍ͨʹग़ͨ͠Γ
    $ perl postderef.pl
    c1,c2,c3
    aa,bb,cc
    dd,ee,ff
    gg,hh,ii
    

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28. Ͳ͏Αʁʁʁʁ
    

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29. ײ૝
    • ϫϯϥΠφʔͱ͔Ͱศརͦ͏
    • jqͷ୅ΘΓʹ࢖͏ͱ͔
    • ͱ͸͍͑·ͣv5.24ʹ্͛Δͱ͜Ζ͔Β……
    

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