Decimal

string

The decimal value, as a string.

The string representation consists of an optional sign, + ( U+002B ) or - ( U+002D ), followed by a sequence of zero or more decimal digits ("the integer"), optionally followed by a fraction, optionally followed by an exponent. An empty string shouldbe interpreted as 0 .

The fraction consists of a decimal point followed by zero or more decimal digits. The string must contain at least one digit in either the integer or the fraction. The number formed by the sign, the integer and the fraction is referred to as the significand.

The exponent consists of the character e ( U+0065 ) or E ( U+0045 ) followed by one or more decimal digits.

Services shouldnormalize decimal values before storing them by:

• Removing an explicitly-provided + sign ( +2.5 -> 2.5 ).
• Replacing a zero-length integer value with 0 ( .5 -> 0.5 ).
• Coercing the exponent character to upper-case, with explicit sign ( 2.5e8 -> 2.5E+8 ).
• Removing an explicitly-provided zero exponent ( 2.5E0 -> 2.5 ).

Services mayperform additional normalization based on its own needs and the internal decimal implementation selected, such as shifting the decimal point and exponent value together (example: 2.5E-1 <-> 0.25 ). Additionally, services maypreserve trailing zeroes in the fraction to indicate increased precision, but are not required to do so.

Note that only the . character is supported to divide the integer and the fraction; , should notbe supported regardless of locale. Additionally, thousand separators should notbe supported. If a service does support them, values mustbe normalized.

The ENBF grammar is:

 DecimalString =
  '' | [Sign] Significand [Exponent];

Sign = '+' | '-';

Significand =
  Digits ['.'] [Digits] | [Digits] '.' Digits;

Exponent = ('e' | 'E') [Sign] Digits;

Digits = { '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' }; 

Services shouldclearly document the range of supported values, the maximum supported precision (total number of digits), and, if applicable, the scale (number of digits after the decimal point), as well as how it behaves when receiving out-of-bounds values.

Services maychoose to accept values passed as input even when the value has a higher precision or scale than the service supports, and shouldround the value to fit the supported scale. Alternatively, the service mayerror with 400 Bad Request ( INVALID_ARGUMENT in gRPC) if precision would be lost.

Services shoulderror with 400 Bad Request ( INVALID_ARGUMENT in gRPC) if the service receives a value outside of the supported range.