It's a bit trickier, than patryk wrote:There are parameters (you can specify several of these at the same time):'i': ONIG_OPTION_IGNORECASE;'x': ONIG_OPTION_EXTEND;'m': ONIG_OPTION_MULTILINE;'s': ONIG_OPTION_SINGLELINE;'p': ONIG_OPTION_MULTILINE | ONIG_OPTION_SINGLELINE;'l': ONIG_OPTION_FIND_LONGEST;'n': ONIG_OPTION_FIND_NOT_EMPTY;'e': eval() resulting codeAnd there are "modes" (if you specify several of these, the LAST one will be used):'j': ONIG_SYNTAX_JAVA;'u': ONIG_SYNTAX_GNU_REGEX;'g': ONIG_SYNTAX_GREP;'c': ONIG_SYNTAX_EMACS;'r': ONIG_SYNTAX_RUBY;'z': ONIG_SYNTAX_PERL;'b': ONIG_SYNTAX_POSIX_BASIC;'d': ONIG_SYNTAX_POSIX_EXTENDED;You can find descriptions of these constants here: http://www.geocities.jp/kosako3/oniguruma/doc/API.txt