Here is my vision. Please entertain it, if you would. If you haven't been able to tell, I'm serious, and I'm a regex fanatic. Learning Perl's Regular Expressions

• Familiarize the reader with the tasks that regular expressions are intended to complete.
  • What is a regular expression (regex)?
  • What can they do?
  • What are some practical uses for them?
  • What are some impractical uses for them?
  • How can they solve daily programming problems?
• Abstract thinking about regexes.
  • How to explain a regex's purpose.
  • How to tackle a given parsing problem with a regex.
  • How to say what you mean, and mean what you say.
  • What else is out there, apart from regexes.
• Simple patterns.
  • Plain text: /hello world/
  • Safe patterns: /hello \Q$place\E/
  • Character classes: /[Hh]ello [Ww]orld/
  • Case-insensitivity: /hello world/i
  • Alternation: /hello|goodbye/
  • Matching something other than $_: $foo =~ /hello/
• More "patterny" patterns.
  • Dot: /h.ll/
  • Quantifiers: /hello(?: +world)?/
  • Macros: /hello\s+world/
  • Anchors: /^hello,?\s+world$/
  • Alternate m// characters: m!a/b/c!
• Getting something back.
  • Capturing: /hello,?\s+(\w+)/
  • Back-references: /\b(\w)\w+(\1)\b/
  • Global matching: /(\d+)/g
  • Regex-y functions: split(), grep(), map()
  • Useful variables: $1, @-, @+
  • Not-so-useful variables: $`, $&, $'
• More modifiers.
  • Modifying .: /a.b/s
  • Modifying ^ and $: /^foo$/m
  • Explaining your regex using /x
  • Using qr// and /o
• Breakpoint: greediness and backtracking
  • What is backtracking, and how does it work?
  • What is greediness, and how do you avoid it?
  • Minimal (lazy) vs. maximal (greedy): /a\w+?z/
  • Understanding the "left-most longest" rule.
• Substitution.
  • Using s///.
  • Calling functions with /e.
• Simple assertions.
  • Positive look-ahead: /foo(?=bar)/
  • Negative look-ahead: /foo(?!bar)/
  • Common traps: "aaabar" =~ /a+(?!bar)/
• More assertions.
  • Positive look-behind: /(?<=foo)bar/
  • Negative look-behind: /(?<!foo)bar/
  • The constant-width assertion plague: /(?<=ab+a)/
  • The cut assertion: /(?>a+)a/
• Logic-flow in regexes.
  • The conditional assertion: /(?(...)a|b)/
• Embedding code.
  • Advanced use of the /e modifier.
  • The evaluate assertion: /(?{ code })/
  • The delayed regex assertion: /(??{ regex })/
• Advanced global searching.
  • The pos() function
  • The \G anchor and the /gc modifiers.
• Common mistakes.
  • $&, et. al.
  • Problems with /$foo/.
  • Matching too much.
  • Wasteful modifiers.
• Optimizing your regexes.
  • "Death to .*."
  • Match only what you want.
  • Unrolling the loop.
• Concrete applications of regexes.
  • Data transformation for sorting.
  • Matching in reverse ("sexeger").
• Regex tools and resources.
  • Komodo
  • YAPE::Regex::Explain
  • Regex::Diagram
  • GraphViz::Regex_YAPE
  • -Dr and -mre=debug

Please give me your input. Is this too much for a tutorial? I want it to be in the form of Learning Perl, with exercises and such, but I want it to include as much as it should so that one has a firm grasp on Perl's regexes.

japhy -- Perl and Regex Hacker

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