As a supplement to the "7 Stages of a Perl Programmer", I present the 7 Stages of Regex Users (as pertains to Perl's special flavor of regexes):

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7 Stages of a Regex User

1. Novice
   • thinks regular expressions are line noise
   • falls prey to "m/usr/bin/" (embedded /'s in m//)
   • has no idea what tr/// is
   • doesn't know about the i modifier
   • gratuitous use of $`, $&, and $'
   • doesn't use \w, \d, \s, etc. metaclasses
   • painfully misuses * and .*
   • puts words in character classes
   
   
2. Initiate
   • still a victim of leaning toothpick syndrome (LTS)
   • uses regexes where chop() or substr() or index() would do
   • tries to use tr/// like s///
   • uses brackets in tr///
   • uses modifiers needlessly (like o, s, and m)
   • does ($x,$y) = ($1,$2), instead of ($x,$y) = /(re)g(ex)/
   • uses | in character classes for alternation
   • uses [^\w] instead of \W
   • tries to delete HTML tags with s/<.*>//g or s/<.*?>//g
   • backslashes needlessly
   
   
3. User
   • uses different m// and s/// delimiters
   • uses regex where index() would do
   • knows about tr///, but uses s/// instead
   • uses regexes in conditionals
   • knows to use the o modifier, but sometimes gets bitten
   • uses backreferences incorrectly sometimes (\1 on the RHS of s///)
   • starts to understand why HTML tags are hard to match with regexes
   
   
4. Adept
   • knows when to use regexes, and when to use string functions
   • knows when to use tr///, and when to use s///
   • leaves the m off // regexes
   • uses the e modifier in s///
   • toys with look-ahead
   • knows to use (?:...) when a backref isn't needed
   • uses precompiled regexes with qr//
   
   
5. Hacker
   • uses look-ahead and look-behind with impunity
   • sighs at the constant-width restraint on look-behind
   • plays with pos() and \G and the g and c modifiers
   • has read "Mastering Regular Expressions"
   • knows how to "unroll the loop"
   • uses re -- and understands the debug output
   • uses closures to make regex matching objects
   • makes nested regexes using (??{...})
   • can read a regex and explain its function
   
   
6. Guru
   • works on the regex engine
   • has patched the engine from time to time
   • uses precompiled regexes as objects
   • refers to "Henry" (that is, Henry Spencer)
   • can explain how any given regex will or won't work
   
   
7. Wizard
   • can add features to the engine at a whim
   • has pumpking status

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japhy -- Perl and Regex Hacker

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