DEELX Regular Expression Match Mode

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DEELX Match Mode

Match modes supported by DEELX : IgnoreCase, Singleline, Multiline, Global, RightToLeft, Extended.

Remarks

IGNORECASE

By default, regular expression is case sensitive. Apply this mode to match case insensitively. But character sets are always case sensitive.

SINGLELINE

By default, the dot can match any character except new-line(\n). SINGLELINE mode will let the dot to match any character.

MULTILINE

Change "^" and "$" from matching the start or end of the string to matching the start or end of any line anywhere within the string.

SINGLELINE and MULTILINE only sound mutually exclusive. They have different function at different places, so they can be used together.

The assertions '\A' and '\Z' are used to match only the beginning and end of the string respectively, regardless of whether the MULTILINE flag has been specified.

GLOBAL

In DEELX, GLOBAL flag only take effect on \G. It let \G to match end of last match when match many times continuously. Without GLOBAL flag, \G has no use in pattern.

By default, the replace operation will replace all matches even GLOBAL is not specified. If you do not want to replace all the matches, you can specify how many times when replace.

RIGHTTOLEFT

Lets regular expression to match from the end of text to the begin. Within the pattern, the expression in the right side will do match first.

To compose a pattern for "RIGHTTOLEFT" is the same as to compose a common pattern. The quantifiers still lays on the right side; ^ still matches the begin of text; Lookahead assertion still matches rightward; The group number still counts from left to right; etc.

In DEELX, the sub-expression within the "forward assertion" is always LEFT to RIGHT match mode, and the sub-expression within the "backward assertion" is always RIGHT to LEFT match mode.

EXTENDED

Let DEELX to ignore white space characters in pattern, and regard characters from # to line end as remark. When EXTENDED mode, use \x20 to stand for space, and use \# to stand for #.

Regardless of whether the EXTENDED flag has been specified, (?# xxx ) is always a remark.