Using Pattern Matching in Rules

You can use the valuePatterns field to achieve pattern matching and identify the specific parts of a statement that need to be rewritten.

If you have specified valuePatterns as part of a rule, all the content that follows the matched pattern is rewritten.

Consider the sample form rule below.

<Form source="*/source.html
" name="form1" field="visit
" [valuePatterns="0|1234|"]/>

where

source is the URL of the html page where the form displays.

name is the name of the form.

field is the field in the form whose value needs to be rewritten.

valuePatterns indicates the portion of the string that needs to be rewritten. All content appearing after valuePatterns is rewritten (optional, default "" means the full value needs to be rewritten).

Specifying Specialized Characters in valuePatterns

You can specify specialized characters by escaping them with a backslash. For example:

<Form source="*/source.html" name="form1" field="visit" [valuePatterns="0|1234|\\;original text|changed text”]/>

Using Wild Cards in valuePatterns

You can use the wildcard asterisk (*) character to achieve pattern matching for rewriting.

You cannot specify just an * in the valuePatterns field. Because * indicates a match with all text, no text follows the valuePattern. Therefore, Rewriter has no text to rewrite. You must use * in conjunction with another string such as *abc. In this case, all content that follows *abc is rewritten.

An asterisk (*) can be used as a wildcard in any of the fields of the rule. However, all the fields in the rule cannot contain an *. If all fields contain a *, the rule is ignored. No error message is displayed.

You can use a * or ** along with the separation character (a semicolon or comma) that displays in the original statement to separate multiple fields. One asterisk (*) matches any field that is not to be rewritten, and two asterisks (**) to match any field that needs to be rewritten.

Using Wild Cards in valuePatterns lists some sample usages of the * wildcard.