I have a pattern that looks like this BNF:
TEXT = 'A' - 'Z' / 'a' - 'z'
DIGIT = '0' - '9'
pattern = 1*TEXT [ ';' 1*DIGIT ]
In English, text, optionally followed by a semicolon and some digits. So
some valid examples:
foo
foo;1
foo;444
Invalid examples are
foo;
foo23
If there's a semicolon, it must be followed by a digit; if there's no
semicolon, no digits.
Am I missing something?
This is the Lua pattern you're searching for: ^(%a+)%f[;%z];?(%d*)%f[;%z]$
for _, s in ipairs{"foo", "foo;1", "foo;444", "foo;", "foo23"} do
local text, digit = string.match(s, "^(%a+)%f[;%z];?(%d*)%f[;%z]$")
print(s, text, digit)
end
