def Char.is_digit
import Base1951def Char.is_digit(c: Char) -> Bool:
1952 match c:
1953 case Chr{+x}:
1954 Bool.and(U32.is_ge(x, 48), U32.is_le(x, 57))
import Base1951def Char.is_digit(c: Char) -> Bool:
1952 match c:
1953 case Chr{+x}:
1954 Bool.and(U32.is_ge(x, 48), U32.is_le(x, 57))