The Expression Builder

The Expression Builder makes it much easier to remember what regular expressions are expressed for various constructs. It will not write your regular expressions for you, but it will save you the luxury of having to remember that an anchor for start of string is expressed as \A whereas a start of line is expressed with the ^ character.

In order to use the Expression Builder, the regex field must have the focus, and the caret must be located at the appropriate location within your regular expression text. Most of the time, this will be at the end of the regular expression, as you build up your regular expression from various fragments.

You can use the Expression Builder from both the Create tab, (via the button as well as the Tools menu item) as you would expect, as well as from the Test tab (there is no button, only from the Tools menu). Although, most likely you will mostly use it from the Create tab.
 

The Expression Builder menu:

The Expression Builder provides a user interface layer for entering cryptic regular expressions. The Expression Builder menu, whether you display it from the Tools menu, or by clicking on the Expression Builder button above the regex field has the following main items:

Literal: Brings up a dialog box immediately allowing you to enter literal text.

Character Shortcuts: Provides the regular expression fragments for common non character values, such as alert, backspace, tab, carriage return, vertical tab, form feed, new line and escape. In addition, you can choose the ASCII Chart item which allows you to select any value from a standard ASCII chart.

Character Classes: Gives you a way to specify alternation and other character classes, such as word, white-space, digit, non-word, non-white-space, and non-digit. You can also choose inclusion and exclusion options through a dialog box.

Anchors: Lets you enter anchors, such as start and end of line or string and end of previous match and word boundary.

Quantifiers: Allow you to enter greedy or lazy quantifiers, including a user interface for entering intervals.

Grouping: Lets you enter capture or non-capture group, named capture and look around.

Backreference: Lets you choose the first, second or third back-reference.

Miscellaneous: Lets you enter regular expression inline comments, and various other options, such as ignoring case, setting multi-line, setting explicit capture, and ignoring pattern white-space. Note that some of these can also be set for .net regular expressions using the Options tab.

Literal Text

Literal text is simple and can be entered through the Insert Literal Test dialog box, as follows:

ASCII Chart

The Insert ASCII Character dialog box shows an ASCII character chart of buttons. As you move the mouse cursor over the grid, you will see the decimal, octal, and hex values for the various ASCII values appear in the Value section of the dialog. A tooltip also appears which provides an explanation for the characters in the ASCII chart.

The following picture shows the Insert ASCII Chart dialog box:

Several abbreviations are used in the ASCII chart to represent common characters. The following table provides an explanation for these characters.
 

When you click a button, the read-only Regular Expression Fragment shows the text that will be inserted in the Regular Expression field.  You can choose to express this value in hex (base 16) or octal (base 8).  Click the Insert button to move the move the regular expression fragment into the regular expression field and close the dialog box. 

Inclusion Classes

The Insert Inclusion dialog box allows you to choose the characters which should be included in a regular expression.  Inclusion characters are those which should be included in a regular expression.  You can choose alphabetic, numeric, alphanumeric, keyboard symbols and a custom setting.  If you are choosing an alphabetic option, you can also choose the appropriate case setting.  When you have chosen your options, the regular expression fragment read only field will show how the fragment will appear.  When you are satisfied with your selection, click on the Insert button.

The Insert Inclusion Dialog Box appears below:

Exclusion Classes

The Insert Exclusion dialog box is similar to the Insert Inclusion dialog box, but specifies those characters that you wish to be excluded for a regular expression.  You can choose alphabetic, numeric, alphanumeric, keyboard symbols and a custom setting.  If you are choosing an alphabetic option, you can also choose the appropriate case setting.  When you have chosen your options, the regular expression fragment read only field will show how the fragment will appear.  When you are satisfied with your selection, click on the Insert button.

The Insert Exclusion Dialog box appears below:

Interval

By choosing the Interval menu and then selection the Interval menu item, the Insert Interval dialog box will be displayed.  The Insert Interval dialog box allows you to choose the options attributed to an interval match.  You can choose an exact match, you can choose at least a certain number of match.  There is also a checkbox for forcing the interval to be lazy. 

When you have chosen your options, the regular expression fragment read only field will show how the fragment will appear.  When you are satisfied with your selection, click on the Insert button.

The Insert Interval Dialog appears as follows:

Capture Groups

There are three options for inserting capture groups: Capture, Named Capture, and Non-Capture group.  The only information required for a capture group is to enter a substring you would like to capture.  When you have chosen your options, the regular expression fragment read only field will show how the fragment will appear.  When you are satisfied with your selection, click on the Insert button.

The Insert Capture Group Dialog appears as follows:

Lookaround

The Insert Lookaround dialog box, found on the Grouping menu item followed by the Lookaround option. Allows you to specify information for entering a lookaround.  Theree are two types:  positive, negative.  You can also choose a negative lookbehind.  All the information you need to enter is the substring.  

When you have chosen your options, the regular expression fragment read only field will show how the fragment will appear.  When you are satisfied with your selection, click on the Insert button.

The Insert Lookaround Dialog appears as follows:

Inline Comments

The Miscellaneous | Insert Comment menu option will display the Insert Comment dialog box.  This simple dialog box takes a single comment string, which is the default field.  When you have chosen your options, the regular expression fragment read only field will show how the fragment will appear.  When you are satisfied with your selection, click on the Insert button.

The Insert Comments Dialog appears as follows: