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Knowledge Base Document #KB-00004

Using ReX-T

Using ReX-T

ReX-T is a tool to develop and try out Regular Expression patterns. You can enter these patterns into the Search Pattern field and apply them to any text that you type (or copy-and-paste) into the Source Text field.

Image Main Window 500x367

When you click the Search button, the matches - if any - are shown in the list below that button.

When you click on a match, the corresponding portion of the source text is highlighted.

If a match has submatches (created by capturing groups in the pattern), the entry in the resut list has a little disclosure triangle next to it. Click on that triangle to „open“ that match and see the submatches.

Search Options

The set of checkbox buttons under the Search Pattern field lets you control how the pattern is applied to your search.

Option Description
Case Insensitive When checked, the pattern does not distinguish between upper- and lowercase letters. That mean that the pattern [a-z] will match the letters a-z as well as A-Z.
Allow Comments and Whitespace This option has two effects. Number one: If it is on, any whitespace (spaces, line breaks and such) that you enter in your pattern will be ignored. If it is off, whitespace characters become part of the pattern, so that A BC (with a space between the A and the B) will only match if there is also a space in the source text at that position. The second effect: It allows you to insert comments in the following form into your pattern:
/* this is a comment */
Such comments will also be ignored when applying the pattern.
Use Unix Line Separators When checked, only Unix-Style line separators (\n, or 0x0a) will be treated as line separators (for example, for the ^ and $ anchors.) Otherwise, all line separator characters are treated as such.
Anchors Match Lines When checked, the anchors ^ and $ will match at line breaks. If not, they will only match at the beginning or end of the source text.
See the corresponding entries in the Pattern Library for details.
Use Unicode Word Boundaries Enabling this option will use a slightly different definition of word boundaries, namely the Unicode TR#29 specification. See UAX #29: Unicode Text Segmentation for details.
Dot Matches Line Separators Enabling this allows the dot metacharacter to also match line breaks. Otherwise it doesn't.
Ignore Metacharacters Makes RegEx "dumb". It will take every character in the pattern literally, so that die dot matches only dots, the asterisk will only match asterisks, end so on.
Anchored This anchors any matches to the beginning and end of the source text (or a line of it, if Anchors Match Lines is enabled) – in other words, changes the match mode from "contains..." to "equals...".

Output Formatting

In order to give a better understanding of the search results, you can choose how to display the matches in the leftmost column of the results table.

The length of an individual match may exceed the column width of the result table. In this case, you can hover your mouse over the result table cell to see full match text in a "tooltip" style bubble.

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help-rext-using-rext, ReX-T