2. What's new in this release

VERSION 1.1 (October 1999)

Regular expression syntax corrections and enhancements:

1. Backslash escapes similar to those in Perl are allowed in patterns:
   
   

   	\w		any word constituent character (equivalent to [a-zA-Z0-9_])
   	\W		any character but a word constituent (equivalent to [^a-xA-Z0-9_]
   	\d		a digit (same as [0-9])
   	\D		anything but a digit
   	\s		a whitespace character
   	\S		anything but a whitespace character
   	\b		an empty string at a word boundary
   	\B		an empty string not at a word boundary
   	\<		an empty string at the beginning of a word
   	\>		an empty string at the end of a word

   For example, '\w+' is now a valid expression matching any word.

2. The following backslash escapes are also allowed in character sets (between square brackets):
   
   

   \w, \W, \d, \D, \s et \S

   
   
3. The following grep(1)-compatible named character classes are recognized in character sets as well:

	[:alnum:]
	[:alpha:]
	[:cntrl:]
	[:digit:]
	[:graph:]
	[:lower:]
	[:print:]
	[:punct:]
	[:space:]
	[:upper:]
	[:xdigit:]


For example, the following patterns are equivalent:



'[[:alnum:]]+' '\w+' '[\w]+' '[a-zA-Z0-9]+'

4. Some non-printable characters can be represented in regular expressions using a common backslash notation:
   
   

   	\t		tab (Character tab)
   	\n		newline (Character lf)
   	\r		carriage return (Character cr)
   	\f		form feed (Character newPage)
   	\e		escape (Character esc)

   
   
5. A dot is corectly interpreted as 'any character but a newline' instead of 'anything but whitespace'.
   
   
6. Case-insensitive matching. The easiest access to it are new messages CharacterArray understands:
   

   	#asRegexIgnoringCase,
   	#matchesRegexIgnoringCase:,
   	#prefixMatchesRegexIgnoringCase:

   
   
7. The matcher (an instance of RxMatcher, the result of String>>asRegex) now provides a collection-like interface to matches in a particular string or on a particular stream, as well as substitution protocol. The interface includes the following messages:
   

   	matchesIn: aString
   	matchesIn: aString collect: aBlock
   	matchesIn: aString do: aBlock
   	matchesOnStream: aStream
   	matchesOnStream: aStream collect: aBlock
   	matchesOnStream: aStream do: aBlock
   	copy: aString translatingMatchesUsing: aBlock
   	copy: aString replacingMatchesWith: replacementString
   	copyStream: aStream to: writeStream translatingMatchesUsing: aBlock
   	copyStream: aStream to: writeStream replacingMatchesWith: aString

   
   Examples :
   

   '\w+' asRegex matchesIn: 'now is the time'

   
   returns an OrderedCollection containing four strings: 'now', 'is', 'the', and 'time'.
   
   

   '\<t\w+' asRegexIgnoringCase     copy: 'now is the time'     translatingMatchesUsing: [:match | match asUppercase]

   
   returns 'now is THE TIME' (the regular expression matches words beginning with either an uppercase or a lowercase T).

ACKNOWLEDGEMENTS

Since the first release of the matcher, thanks to the input from several fellow Smalltalkers, I became convinced a native Smalltalk regular expression matcher was worth the effort to keep it alive. For the advice and encouragement that made this release possible, I want to thank:

and anyone whom I haven't yet met or heard from, but who agrees this has not been a complete waste of time.

--Vassili Bykov
October 3, 1999

Updated on 2002-03-10