Function StartsExponent

cpp/src/arrow/util/decimal.cc:806–806

inline bool IsDigit(char c) { return c >= '0' && c <= '9'; }

inline bool StartsExponent(char c) { return c == 'e' || c == 'E'; }

inline size_t ParseDigitsRun(const char* s, size_t start, size_t size,
                             std::string_view* out) {