book

Mastering Perl

by brian d foy

July 2007

Beginner

342 pages

8h 30m

English

O'Reilly Media, Inc.

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Structure of This BookConventions Used in This BookUsing Code ExamplesSafari® EnabledComments and QuestionsAcknowledgments
What It Means to Be a MasterWho Should Read This BookHow to Read This BookWhat Should You Know Already?What I CoverWhat I Don’t Cover
References to Regular Expressions(?imsx-imsx:PATTERN)References As ArgumentsNoncapturing Grouping, (?:PATTERN)Readable Regexes, /x and (?#...)Global MatchingGlobal Match AnchorsLookaroundsLookahead Assertions, (?=PATTERN) and (?!PATTERN)Positive lookahead assertionsNegative lookahead assertionsLookbehind Assertions, (?<!PATTERN) and (?<=PATTERN)Deciphering Regular ExpressionsFinal ThoughtsSummaryFurther Reading
Bad Data Can Ruin Your DayTaint CheckingWarnings Instead of Fatal ErrorsAutomatic Taint Modemod_perlTainted DataSide Effects of Taint CheckingUntainting DataIO::Handle::untaintHash KeysChoosing Untainted Data with Tainted DataList Forms of system and execThree-Argument opensysopenLimit Special PrivilegesSummaryFurther Reading
Before You Waste Too Much TimeThe Best Debugger in the WorldDoing Whatever I WantProgram TracingSafely Changing ModulesWrapping Subroutinesperl5db.plAlternative DebuggersUsing a Different Debugger with -DDevel::ptkdbDevel::ebugOther DebuggersEPICKomodoAffrusSummaryFurther Reading
Finding the CulpritThe General ApproachProfiling DBIOther DBI::Profile ReportsMaking It Even EasierSwitching DatabasesDevel::DProfWriting My Own ProfilerDevel::LineCounterProfiling Test SuitesDevel::CoverSummaryFurther Reading
Benchmarking TheoryBenchmarking TimeComparing CodeDon’t Turn Off Your Thinking CapMemory UseThe perlbench ToolSummaryFurther Reading

Good StyleperltidyDe-ObfuscationDe-Encoding Hidden SourceUnparsing Code with B::DeparsePerl::CriticCreating My Own Perl::Critic PolicySummaryFurther Reading
Package and Lexical VariablesGetting the Package VersionThe Symbol TableTypeglobsAliasingFilehandle Arguments in Older CodeNaming Anonymous SubroutinesSummaryFurther Reading
Subroutines As DataCreating and Replacing Named SubroutinesSymbolic ReferencesIterating Through Subroutine ListsProcessing PipelinesMethod ListsSubroutines As ArgumentsAutoloaded MethodsHashes As ObjectsAutoSplitSummaryFurther Reading
Choosing the Right SolutionSending Patches to the AuthorLocal PatchesTaking over a ModuleForkingStart Over on My OwnReplacing Module PartsSubclassingAn ExtUtils::MakeMaker ExampleOther ExamplesWrapping SubroutinesSummaryFurther Reading
Things Not to DoCode in a Separate FileBetter WaysEnvironment VariablesSpecial Environment VariablesTurning on Extra OutputCommand-Line SwitchesThe -s SwitchGetopt ModulesGetopt::StdGetopt::LongConfiguration FilesConfigReader::SimpleConfig::IniFilesConfig::ScopedAppConfigOther Configuration FormatsScripts with a Different NameInteractive and Noninteractive Programsperl’s ConfigDifferent Operating SystemsSummaryFurther Reading
Perl Error BasicsOperating System ErrorsChild Process ErrorsErrors Specific to the Operating SystemReporting Module ErrorsSeparation of ConcernsExceptionsevalMultiple Levels of diedie with a ReferencePropagating Objects with dieFatalSummaryFurther Reading
Recording Errors and Other InformationLog4perlConfiguring Log4perlPersistent LoggingOther Log::Log4perl FeaturesSummaryFurther Reading
Flat FilespackData::DumperSimilar ModulesYAMLStorableFreezing DataDBM FilesdbmopenDBM::DeepSummaryFurther Reading
The Pod FormatDirectivesBody ElementsMultiline CommentsTranslating PodPod TranslatorsPod::Perldoc::ToTocPod::SimpleSubclassing Pod::SimplePod in Your Web ServerTesting PodChecking PodPod CoverageHiding and Ignoring FunctionsSummaryFurther Reading
Binary NumbersWriting in BinaryBit OperatorsUnary NOT, ~Bitwise AND, &Binary OR, |Exclusive OR, ^Left << and right >> shift operatorsBit VectorsThe vec FunctionBit String StorageStoring DNAKeeping Track of ThingsSummaryFurther Reading
They Look Like Normal VariablesAt the User LevelBehind the CurtainScalarsTie::CycleBounded IntegersSelf-Destructing ValuesArraysReinventing ArraysSomething a Bit More RealisticHashesFilehandlesSummaryFurther Reading
The main ThingBacking UpWho’s Calling?Testing the ProgramCreating the Program DistributionAdding to the ScriptDistributing the ProgramsSummaryFurther Reading
Perl BooksNon-Perl Books
My Philosophy of Problem-SolvingMy Method

Content preview from Mastering Perl

Appendix B. brian’s Guide to Solving Any Perl Problem

After several years of teaching Perl and helping other people solve their Perl problems, I wrote a guide that showed how I think through a problem. It’s appeared on a couple of web sites and there are even a couple of translations.^[65]Some of the stuff I did unconsciously, and those are the hardest things to pass on to a new programmer. Now that I have this guide, other people can develop their own problem-solving skills. It might not solve all of your Perl problems, but it’s a good way to try.

My Philosophy of Problem-Solving

I believe in three things when it comes to programming, or even anything else I do.

It is not personal

Forget about code ownership. You may think yourself an artist, but even the Old Masters produced a lot of crap. Everybody’s code is crap, which means my code is crap and your code is crap. Learn to love that. When you have a problem, your first thought should be “Something is wrong with my crappy code.” That means you do not get to blame Perl. It is not personal.

Forget about how you do things. If the way you did things worked, you would not be reading this. That is not a bad thing. It is just time to evolve. We’ve all been there.

Personal responsibility

If you have a problem with your program it is just that—your problem. You should do as much to solve it by yourself as you can. Remember, everyone else has their own programs, which means they have their own problems. Do your homework and give it your best shot ...