Advanced Regular Expressions

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Advanced Regular Expressions

• Or
• Whats special about
• RegEx in MX

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Your Presenter

• Michael Dinowitz
• Head of House of Fusion
• Publisher of Fusion Authority
• Founding member of Team Macromedia
• Doing this since June 95
• Called on for the black magic code

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Disclaimer Introduction

• If you dont know the basics get out
• No real changes from CF 5 or CFMX 6

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Basic additions

• Greedy vs. Lazy
• is one or more and as many as it can
• ? Is one or more but only as many as it needs
• Same as greedy but does not allow back
  references (not in CFMX)
• Nested sub expressions
• In order of execution from outside it
• Then left to right

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Character Vs. Posix classes

• Non-special characters become special
• Uses a backslash (\) to specify being special
• Shorter than posix classes
• Harder to read for newbies

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Basic Character Classes

• \b word boundary
• Any jump from alphanumeric to non-alphanumeric
• refindnocase('\bbig\b', 'big')
• \B any 2 of the same types of characters
• refindnocase('\B', 'big') 2

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More Character Classes

• \A - same as (not combined with (?m)
• \Z same as (not combined with (?m)
• \n newline
• \r carriage return
• \t tab
• \d any digit (0-9)
• \D any non digit (0-9)

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More Character Classes

• \w - Any alphanumeric character (alnum )
• \W - Any non-alphanumeric character (alnum
  )
• \s - Any whitespace character including tab,
  space, newline, carriage return, and form feed
  (\t\n\r\f )
• \S any non-whitespace character ( \t\n\r\f)

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Expression Modifiers

• At beginning of expression
• (?i) Causes expression to be case insensitive
  (same as NoCase version)
• (?m) Multi-line mode
• and matches line, not entire string
• Carriage return Chr(13) is ignored as new line

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Expression Modifiers

• (?x) ignores all white space
• Also allows usage of for comments
• will comment to end of line
• reFind("(?x) one first option
• two second option
• three\ point\ five note escaped spaces
• ", "three point five")

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Group Modifiers

• Affects only the group its in
• Must be at beginning of group
• (?) comment
• Must escape
• (?) does not add group to return collection
• (?) Positive look ahead
• (?!) negative look ahead

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Positive Lookahead

• Tests if the text in the parenthesis exists
• Does not save the text into return collection
• Does not consume text
• lta(?.href).?href"(").?gt

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Negative Lookahead

• Tests if the text in the parenthesis does not
  exist
• Does not save the text into return collection
• Does not consume text
• (lta(?!.?target) gtgt)

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Replace conversion

• Used in REReplace()/REReplaceNoCase()
• Either converts the next character or a
  specific section of characters
• \u converts next character to uppercase
• \l converts the next character to lowercase
• \U\E converts block to uppercase
• \L\E converts block to lowercase

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Not Supported

• Positive Lookbehinds
• Negative Lookbehinds
• Other features
• All accessible through the Java RegEx engine
• Massimo has a CFC pre-built to do this

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Resources

• Chapters in most CFMX books
• CF-RegEx mailing list
• This presentation
• Books
• Mastering Regular Expressions, 2nd Edition
• Teach Yourself Regular Expressions in 10 Minutes
• Java Regular Expressions Taming the java Dot util
  Dot regex Engine