Expands regular expressions by expanding the character classes. Supports
[:xdigit:] and allows for addition of other character classes.
rgxOrCharClsNameis a string this should be defined and should be the definition of the character class without brackets. This character class will be added and will be used to expand future regular expressions passed into this function.
rgxOrCharClsNameis a regular expression this will be a modified version of it with the character classes expanded, otherwise this will be a boolean value indicating if the character class was successfully added.
This function directly requires the following functions which are included automatically: