vgrindefs uses regular expression which are very similar to those of
ex(1) and
lex(1). The characters `^', `$', `:' and `\' are reserved characters and must be "quoted" with a preceding ‘\' if they are to be included as normal characters. The metasymbols and their meanings are:
^
the beginning of a line
\d
a delimiter (space, tab, newline, start of line)
\a
matches any string of symbols (like .* in lex)
\p
matches any alphanumeric name. In a procedure definition (pb) the string that matches this symbol is used as the procedure name.
\e
preceding any string means that the string will not match an input string if the input string is preceded by an escape character (\). This is typically used for languages (like C) which can include the string delimiter in a string by escaping it.
Unlike other regular expressions in the system, these match words and not characters. Hence something like "(tramp|steamer)flies?" would match "tramp", "steamer", "trampflies", or "steamerflies".