. Match any character.
^ Match begin of line.
$ Match end of line.
\< Match begin of word.
\> Match end of word.
\B not at edge of a word (supposed to be like the emacs compatibility one in gnu egrep), since 3.2@249
x|y Match regexp x or regexp y.
() Match enclosed regexp like a 'simple' one.
x* Match any number (0 or more) of regexp x.
[..] Match one of the characters enclosed.
[^ ..] Match none of the characters enclosed. The .. are to replaced by single characters or character ranges [abc] matches a, b or c. [ab0-9] matches a, b or any digit. [^a-z] does not match any lowercase character.
\c match character c even if it's one of the special characters.
If there is an error in the regular expression 0 will be returned. Remember that the character "\" has to be escaped with a "\" when written as a LPC string.
string strs;
if (strs = regexp( ({"please, help me Sir John."}),
"\\<help\\>.*\\<me\\>"))
if (sizeof(strs)
write("It matches.\n");
The regular expression will test the given string (which is
packed into an array) if there is something like "help ... me"
inside of it.