Pure mruby Regexp
.Any single character?Zero or one*Zero or more+One or more??Zero or one (reluctant)*?Zero or more (reluctant)+?One or more (reluctant)?+Zero or one (possessive)*+Zero or more (possessive)++One or more (possessive){N}N times{N,}N or more{,N}N or less{N,M}Between N and M{N,}?N or more (reluctant){,N}?N or less (reluctant){N,M}?Between N and M (reluctant)^Start of line$End of line|Alternation[]Character class[^]Negated character class()Group(?<name>)Named group(?'name')Named group(?:)Non-capturing group(?>)Atomic group\wWord character\WNon-word character\sWhitespace character\SNon-whitespace character\dDigit\DNon-digit\hHexadecimal digit\HNon-hexadecimal digit
\NSubmatch\&Entire match\`Substring before match\'Substring after match\+Last submatch\k<name>Named submatch
/iCase insensitive/mMultiline mode