Regular Expressions in Renamer Plugin

The Renamer plugin uses more powerful regular expressions than the Find and Internal Viewer in Sally. It extends the REGEXP library, the great work of Henry Spencer. First read the Regular Expressions Syntax in Sally, then continue with the description of Renamer extensions. These extensions were inspired by Perl.

Extended syntax

'*?' - non-greedy variant of '*' (match 0 or more times)
'+?' - non-greedy variant of '+' (match 1 or more times)
'??' - non-greedy variant of '?' (match 0 or 1 times)
'$' - at the end of the expression matches the end of a line (or before newline at the end)
'( )' - glues expressions in parentheses into one expression and captures a matched substring (see this example to understand how it works)
'(?: )' - works like "( )", but does not capture a matched substring

Note: "non-greedy" means that it matches the minimum number of times possible.

Zero-width assertions

You can use the following zero-width assertions (these do not match any character, but test whether a condition is true or false):

Assertion	Meaning
\b	Match a word boundary.
\B	Match a non-(word boundary).
\A	Match only at beginning of string.
\Z	Match only at end of string, or before newline at the end.
\z	Match only at end of string.
(?= )	Positive look-ahead assertion (for example, 'j(?=ohn)' matches 'j' in word 'john' but not in word 'june').
(?! )	Negative look-ahead assertion (for example, 'j(?!ohn)' matches 'j' in word 'june' but not in word 'john').
(?<= )	Positive look-behind assertion (for example, '(?<=joh)n' matches 'n' in word 'john' but not in word 'joan').
(?<! )	Negative look-behind assertion (for example, '(?<!joh)n' matches 'n' in word 'joan' but not in word 'john').

Within character classes "\b" represents backspace rather than a word boundary.

POSIX character classes

You can use the following POSIX character classes:

Class	Backslash Equivalent	Meaning
alpha		Alphabetic characters.
alnum		Alphanumeric characters.
ascii		ASCII characters.
cntrl		Control characters.
digit	\d	Decimal digits.
graph		Characters that are both printable and visible (a space is printable but not visible).
lower		Lowercase alphabetic characters.
print		Printable characters (characters that are not control characters).
punct		Punctuation characters (characters that are not letters, digits, control characters, or space characters).
space	\s	Spacing characters (e.g. space, TAB, formfeed).
upper		Uppercase alphabetic characters.
word	\w	Alphanumeric characters plus underscore ("_").
xdigit		Characters that are hexadecimal digits.

You can negate the character classes by prefixing the class name with a '^'.

Usage: [[:alpha:]] (alphabetic characters), [01[:alpha:]%] (alphabetic characters plus 0, 1, and %), [[:^digit:]] (all characters except decimal digits).

Short forms of some character classes

You can use the following short forms of character classes:

Class	Meaning
\w	Alphanumeric characters plus underscore ("_").
\W	All characters except alphanumeric characters and underscore ("_").
\s	Spacing characters (e.g. space, TAB, formfeed).
\S	All characters except spacing characters (e.g. space, TAB, formfeed).
\d	Decimal digits.
\D	All characters except decimal digits.

Special characters

You can use the following special characters:

Special character	Meaning
\t	tab
\n	newline
\r	return
\f	formfeed
\a	alarm (bell)
\b	backspace
\x5A	character 'Z' with ordinal 0x5A (hexadecimal value)