Pattern Matching

Opie provides pattern matching using regular expressions or wildcards.
It supports unicode and character sets.

Regular Expressions

Regular Expressions knows these primitives:

c matches the character 'c'
. matches any character
^ matches start of input
$ matches end of input
[] matches a defined set of characters - see below.
a* matches a sequence of zero or more a's
a+ matches a sequence of one or more a's
a? matches an optional a
\c escape code for matching special characters such as \, [, *, +, . etc.
\t matches the TAB character (9)
\n matches newline (10)
\r matches return (13)
\s matches a white space (defined as any character for which QChar::isSpace() returns TRUE. This includes at least ASCII characters 9 (TAB), 10 (LF), 11 (VT), 12(FF), 13 (CR) and 32 (Space)).
\d matches a digit (defined as any character for which QChar::isDigit() returns TRUE. This includes at least ASCII characters '0'-'9').
\x1f6b matches the character with unicode point U1f6b (hexadecimal 1f6b). \x0012 will match the ASCII/Latin1 character 0x12 (18 decimal, 12 hexadecimal).
\022 matches the ASCII/Latin1 character 022 (18 decimal, 22 octal).

wildcard mode

In wildcard mode, it only knows four primitives:

c matches the character 'c'
? matches any character
* matches any sequence of characters
[] matches a defined set of characters - see below.

General

It supports Unicode both in the pattern strings and in the strings to be matched.

A character set matches a defined set of characters. For example, [BSD] matches any of 'B', 'D' and 'S'. Within a character set, the special characters '.', '*', '?', '^', '$', '+' and '[' lose their special meanings. The following special characters apply:

^ When placed first in the list, changes the character set to match any character not in the list. To include the character '^' itself in the set, escape it or place it anywhere but first.
- Defines a range of characters. To include the character '-' itself in the set, escape it or place it last.
] Ends the character set definition. To include the character ']' itself in the set, escape it or place it first (but after the negation operator '^', if present)

Thus, [a-zA-Z0-9.] matches upper and lower case ASCII letters, digits and dot; and [^\s] matches everything except white space.

Bugs and limitations:

Case insensitive matching is not supported for non-ASCII/Latin1 (non-8bit) characters.