package syntax func isSpace(ch byte) bool { switch ch { case '\r', '\n', '\t', '\f', '\v': return true default: return false } } func isAlphanumeric(ch byte) bool { return (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') || (ch >= '0' && ch <= '9') } func isDigit(ch byte) bool { return ch >= '0' && ch <= '9' } func isOctalDigit(ch byte) bool { return ch >= '0' && ch <= '7' } func isHexDigit(ch byte) bool { return (ch >= '0' && ch <= '9') || (ch >= 'a' && ch <= 'f') || (ch >= 'A' && ch <= 'F') }