August 2004 - Posts

• Examining the data flow model of using DateTime as a Parser for Dates

  Yet another diagram here. This time we get to see some differences between a parser/validator model where the pieces are separated for purposes of providing enhanced user feedback and more specialized return structures. The end result is that we are able Read More... Posted Saturday, August 14, 2004 9:55 PM by jrogers | 1 Comments Filed under: Regular Expressions, Lexing and Parsing

• Examining the data flow model of using Regular Expressions for Dates

  I think some diagrams are going to be extremely important for examining the problems of using regular expressions for validating and parsing dates. Especially as you start to rely on more and more complex and time consuming operations to validate additional Read More... Posted Saturday, August 14, 2004 4:18 PM by jrogers | 0 Comments Filed under: Regular Expressions

• Performance: Character Classes versus Alternation Groups

  If heated discussion with Michael Ash keeps resulting in this sort of performance break-through then I'll argue with him every day of the week. To follow the performance examinations you are going to have to make sure that both Compiled and ExplicitCapture Read More... Posted Saturday, August 14, 2004 3:53 AM by jrogers | 0 Comments Filed under: Regular Expressions

• Expressions, Parsers, Validators, User Feedback and the tradeoffs we make.

  While the traffic has a local nature to regexadvice.com/blogs, there has been a lot of examination of various expressions where a date processing expression has become the topic of note. Personally, I have huge problems with constantly having a date expression Read More... Posted Tuesday, August 10, 2004 9:04 PM by jrogers | 1 Comments Filed under: Regular Expressions, Lexing and Parsing

• What does conditional matching really mean in a regular expression?

  Darren recently drew an example, but even though I'm Regex adept, I didn't find his meaning Conditional Matching . He basically shows a way to match Thur in Thursday or Thurday, but then if there is an s, make sure that day also follows. Now I would assert Read More... Posted Tuesday, August 10, 2004 2:02 AM by jrogers | 2 Comments Filed under: Regular Expressions

• The not so basics of NOT!

  It is very easy to build a regular expression that matches a particular pattern, but not one that matches the absence of a pattern. Thankfully we've been given some tools in the form of assertions that make the ability to perform a NOT operation quite Read More... Posted Friday, August 06, 2004 1:50 AM by jrogers | 1 Comments Filed under: Regular Expressions