-- Pattern-matching corners that already match reference Lua 5.5.
print(("a1 B2"):gsub("%a", "X"), ("a1 B2"):gsub("%d", "D"), ("a1 B2"):gsub("%s", "_"))
print(("THE (quick) fox"):gsub("%f[%a]%a+%f[%A]", "W"))
print(("a-b.c"):gsub("[%-.]", "/"), ("hello"):gsub("[aeiou]", "*"))
print(("hello world"):match("(%w+)%s+(%w+)"))
print(("abcabc"):match("(abc)%1"))
print(("hello"):match("l()l"))
print(("abc"):gsub("%a", function(c) if c == "b" then return "B" end end))
print(("$a $b"):gsub("%$(%w+)", { a = "1", b = "2" }))
print(("aaaa"):gsub("a", "b", 2))
print(("(a(b)c)"):match("%b()"))