"?"
"abc"
"()"
"[]"
"abc|def"
"abc|def|ghi"
"^xxx$"
"ab\\b\\d\\bcd"
"\\w|\\d"
"a*?"
"abc+"
"abc+?"
"xyz?"
"xyz??"
"xyz{0,1}"
"xyz{0,1}?"
"xyz{93}"
"xyz{1,32}"
"xyz{1,32}?"
"xyz{1,}"
"xyz{1,}?"
"a\\fb\\nc\\rd\\te\\vf"
"a\\nb\\bc"
"(?:foo)"
"(?: foo )"
"foo|(bar|baz)|quux"
"foo(?=bar)baz"
"foo(?!bar)baz"
"foo(?<=bar)baz"
"foo(?)"
"(?.)"
"(?.)\\k"