The set of regular expressions that the debugger supports for matching symbols is similar to the set supported by UNIX grep. The debugger set includes a few enhancements.
Following are the wildcards:
| Wildcard | Description |
|---|---|
| . | Matches any single character. |
| [ ] | Defines a character class; matches a set or range of characters. |
| ^ | Negates a character class. |
Following are the postfix operators:
| Operator | Description |
|---|---|
| * | Causes the previous wildcard or single character to match zero or more characters. |
| # | Matches zero or one. |
| + | Plus sign, matches one or more. |
Anywhere a symbol is accepted, a regular expression can be used. If there is more than one match, a list of matching symbols is displayed and you must select the proper symbol. The symbol match is not case-sensitive.
The asterisk (*), number sign (#), and plus sign (+) are already math expression operators. To be recognized as a regular expression operator, each of these characters must be immediately preceded by an escape character — the backslash (\). The period (.), opening bracket ([), and closing bracket (]) do not require escape characters. Anything inside the brackets of a character class does not have to be escaped. Following are valid character classes:
[a-z]
[;*+#]
Characters are escaped at two levels: in the expression evaluator and in the regular expression parser. A character special to the expression evaluator (*, #, +, or \) must be escaped to make it to the regular expression parser. If a character special to the regular expression parser must be escaped (for example, to match symbols with * or # in them), it must be escaped twice. If a backslash is needed in an expression, it must be double escaped.
Following are sample regular expressions:
| Regular expression | Description |
|---|---|
| sym.\* | Matches any symbols beginning with the string sym. |
| sym\* | Matches sym alone and sym followed by any characters. |
| .\*sym.\* | Matches any symbols containing the string sym. |
| sym[0–9] | Matches sym0, sym1, sym2, and so on. |
| sym\\\* | Matches sym*. |
| sym\\\\ | Matches sym\. |
| sym\\\\.\* | Matches any symbols beginning with the string sym\. |