![Regexp Keep it simple! $foo =~ s{foo}{bar}g; $html =~ s/<(?:[^>'"]*|(['"]).*?\1)*>//gsx Add comments to big Regexp chunks Use \A and \Z instead of $ and ^ s{ < # opening angle bracket (?: # Non-backreffing grouping paren [^>'"] * # 0 or more things that are neither > nor ' nor " | # or else ".*?" # a section between double quotes (stingy match) | # or else '.*?' # a section between single quotes (stingy match) ) + # all occurring one or more times > # closing angle bracket }{}gsx; # replace with nothing, i.e. delete](https://image.slidesharecdn.com/cleancode-090419053418-phpapp01/85/Cleancode-19-320.jpg)
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Cleancode
- 1. Clean Code Hendrik Van Belleghem Belgian Perl Workshop 2007
- 2. Itโs all Bruces fault!
- 3. Obviously? Pragmas warnings strict subs : no barewords! refs : no symbolic references! vars : no undeclared variables!
- 4. Obviously? Variable names Variable names should be Short but not too short $i, $a, $o Unambiguous $i, $data, $line
- 5. Obviously? Variable names Variable names should definitely not be generated by Acme::MetaSyntactic: $thwacke # batman $flrbbbbb # batman $bondelschwaartz #pynchon $ununquadium # elements
- 6. Acme::Metasyntactic? Itโs all BooKโs fault!
- 7. Obviously? Variable names Scalars are single $item Hashes and arrays are plural @items Mark booleans with test $found_match Add reference prefix/suffix $item_ref
- 8. Braces.. bad? Array definition my @list = ( โlarryโ, โ damianโ ); Any other block? for my $coder ( @list ) { print โhi $coder\nโ; }
- 9. Braces..good? Array definition my @list = ( โ larryโ, โ damianโ ); Any other block? for my $coder ( @list ) { print โhi $coder\nโ; }
- 10. Stay away from $_ $_ as default argument? -X, abs, alarm, chomp, chop, chr, chroot, cos, defined, eval, exp, glob, hex, int, lc, lcfirst, length, log, lstat, oct , ord, pos, print, quotemeta, readlink, ref, require, reverse, rmdir, sin, split, sqrt, stat, study, uc, ucfirst, unlink Implicit use m//, s///, y/// for(), map {}, grep {}, while(<>) default input and pattern matching space
- 11. Postfix if buy("secret lair") and buy("sharks with lasers") and $mini_me = clone() if $goal eq "world domination"; if ($goal eq โworld dominationโ) { buy(โsecret lairโ); buy(โsharks with lasersโ); $mini_me = clone(); }
- 12. C style loops for (my $slide = 1; $slide < 25 ; $slide++) { present($slide); } for my $slide (1..25) { present($slide); } Cleaner Easier to read
- 13. POD Put POD in the source file.. At the end Check your POD! Podchecker Use POD templates & stubs NAME, VERSION, SYNOPSIS,..
- 14. String eval is bad Donโt overuse eval.. Period String eval is recompiled on execution Use block instead Are you taint-checking??
- 15. Filehandles Bareword filehandles Cannot be localized Passing it to a sub? Try typeglobs Better: indirect filehandles From 5.6 onwards open my $filehandle, โ<filenameโ or die $!;
- 16. Regexp::Common IP addresses? $ip =~ /$RE{net}{IPv4}/ MAC addresses? $ip =~ /$RE{net}{MAC}/ Credit cards $number =~ /$RE{zip}{VISA}/ For all your extraordinary regexp needs
- 17. Regexp::Common? Itโs all Abigails fault! Dutch Tall Strapping hunk of manhood For all your extraordinary regexp needs
- 18. Regexp Delimiters Question.. What does this do? harry s truman was the 33rd u.s. president; harry s |ruman was |he 33rd u.s. presiden|; harry($string =~ s{ruman was }{he 33rd u.s. presiden}xms);
- 19. Regexp Keep it simple! $foo =~ s{foo}{bar}g; $html =~ s/<(?:[^>'"]*|(['"]).*?\1)*>//gsx Add comments to big Regexp chunks Use \A and \Z instead of $ and ^ s{ < # opening angle bracket (?: # Non-backreffing grouping paren [^>'"] * # 0 or more things that are neither > nor ' nor " | # or else ".*?" # a section between double quotes (stingy match) | # or else '.*?' # a section between single quotes (stingy match) ) + # all occurring one or more times > # closing angle bracket }{}gsx; # replace with nothing, i.e. delete
- 20. Autoload Inheritence precedence? Catch all method
- 21. Refactoring Original code Duplicated code Move to subroutines Duplicated subroutines Move to packages No overkill!
- 22. Tests Write tests first Test::Simple & Test::More Test for failures Test the obvious & not so obvious Find a bug? Write a test!
- 23. Version control Multiple developers Undo Generate patches Merging/branching CVS, Subversion, RCS, Perforce, BitKeeper, git
- 24. Format Compile time definition No runtime changes Except with eval Global variables only Output to named filehandle
- 25. Tie Unknown magic Unpredictable behavior Eg: Tie::Scalar::RestrictUpdates limits changes Slow Change variable behavior through code
- 26. Perl::Critic As Module As command line tool As website : http://perlcritic.com DIY Configurable
- 27. Perl::Critic As Module use Perl::Critic; my $file = shift; my $critic = Perl::Critic->new(); my @violations = $critic->critique($file); print @violations;
- 28. Perl::Critic As command line tool lenore:~$ perlcritic -stern strict.pm Code before strictures are enabled at line 3, column 1. See page 429 of PBP. (Severity: 5) Code before warnings are enabled at line 3, column 1. See page 431 of PBP. (Severity: 4) Always unpack @_ first at line 11, column 1. See page 178 of PBP. (Severity: 4) Subroutine does not end with "return" at line 11, column 1. See page 197 of PBP. (Severity: 4) Always unpack @_ first at line 27, column 1. See page 178 of PBP. (Severity: 4) Subroutine does not end with "return" at line 27, column 1. See page 197 of PBP. (Severity: 4) Always unpack @_ first at line 32, column 1. See page 178 of PBP. (Severity: 4) Subroutine does not end with "return" at line 32, column 1. See page 197 of PBP. (Severity: 4)
- 29. Perl::Critic As website : http://perlcritic.com
- 30. Perl::Critic As Module As command line tool As website : http://perlcritic.com DIY Lots of policies Configurable
- 31. Thank you! ใฉใใใใใใจใใในใฟใผใญใใใ (domo arigato, Mr Roboto)