Extended syntax mode.
property ModifierX: boolean;
Extend your pattern's legibility by permitting whitespace and comments.
Modifier /x tells the TecRegExpr to ignore whitespace that is neither backslashed nor within a character class. You can use this to break up your regular expression into (slightly) more readable parts. The # character is also treated as a metacharacter introducing a comment, for example:
( (abc) # comment 1 | # You can use spaces to format regular expressions - TecRegExpr ignores it (efg) # comment 2 )
This also means that if you want real whitespace or # characters in the pattern (outside a character class, where they are unaffected by /x), that you'll either have to escape them or encode them using octal or hex escapes. Taken together, these features go a long way towards making regular expressions text more readable.