![]() These names aren't sensitive to case: is the same as The special character names and the corresponding characters are: The named notation is provided as anĪlternative because it often results in expressions that are easier to The named character notation is equivalent to using % to quote For example, this is a valid regular expression: The simplest kind of regular expression is simply a string of Isn't too large, though, so it doesn't take too long to learn what TheĪdvantage is that it's a very compact syntax, but at the cost of The syntax for regular expressions is a bit scary at first,īecause it's almost completely based on punctuation marks. Specify a pattern that matches an infinite number of possibilities What makes regular expressions powerful is that youĬan specify a whole range of possibilities without actually listingĪll of the possibilities individually. Rather specifies a sort of "wildcard" pattern that can match many The line feed (LF) character (code u000A)Ī regular expression is sometimes called a "pattern," because itĭoesn't usually specify a literal string of characters to find, but The carriage return (CR) character (code u000D) (?: ) Non-capturing group (?= ) Positive look-ahead assertion (?! ) Negative look-ahead assertion (? The character " The character ">" ( named characters) The following special character (except "") Find the match that ends earliest in the search text Make the match insensitive to case Find the match that begins earliest in the search text (default) %w Match any single word character %W Match any single non- word character Make the match case-sensitive (default) %v Match anything except a vertical whitespace character %v Match any vertical whitespace character % Match only at the end of a word %b Match at any word boundary %B Match only at a non- word boundary %d Match any digit character %9 Match the same text as the ninth parenthesized group %2 Match the same text as the second parenthesized group %1 Match the same text that the first parenthesized group matched Any digit character, or either "x" or "y" Any character in "a" through "f" or "w" through "z" Any character in the range a-z (equivalent to ) Unicode line separator (u2028), Unicode paragraph separator (u2029) Any single newline character: carriage return (u000D), Any single alphabetic or digit character Any single lower-case alphabetic character Any single upper-case alphabetic character ![]() Match any single character ^ Match only at beginning of string $ Match only at end of string Character range Exclusive character range Any single alphabetic character Match at least n and at most m repetitions ? Repeat preceding expression zero or one times * Repeat preceding expression zero or more times ![]() ![]() +? Repeat expression one or more times, taking + Repeat preceding expression one or more times You can define static RexPattern objects using the regular Regular expressions are used, refer to RexPattern intrinsic class, which storesĬompiled patterns, and the specific regularĮxpression functions, rexMatch(), rexSearch(), rexReplace(), and rexGroup(). Users, you'll also find details of the TADS implementation and syntaxįor more information on the specific functions and objects where Introduction for regular expression novices. It tries toĮxplain the concepts involved, so that it can serve as a good The table to note where the TADS syntax differs from what you'reĪfter the table, there's a tutorial and detailed reference,Ĭovering all of the TADS regular expression features. With regular expressions from other languages, you might want to scan The table below is a quick-reference summary of all of the TADS If you'reįamiliar with Perl or Javascript, the TADS syntax will be immediately Not so slightly) from one implementation to the next. Systems, TADS included, with the rest varying slightly (or sometimes There's aĬore of about 80% of the syntax that's identical in most modern Standard syntax that grew out of the Unix "grep" language. Modern regular expression systems have converged on a mostly Probably find the TADS implementation very similar to what you're used to. If you've used other languages with regular expressions, you'll A regular expression is a string matching pattern that'sĪ little bit like a "wildcard" string often used in file system TADS provides a powerful string processing feature known as regularĮxpressions. ![]()
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