Use exponential notation for rendering Amount values#104
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Use exponential notation for rendering Amount values#104jessealama wants to merge 17 commits intomainfrom
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Co-authored-by: Richard Gibson <richard.gibson@gmail.com>
Adds two abstract operations to Amount: - RenderStringInExponentialNotation: takes a String in StrDecimalLiteral form and rewrites it in canonical exponential form (one nonzero integer digit, optional fractional part, signed unpadded exponent), preserving the precision of the input. It uses StringIntlMV to recover the mathematical value and significant-digit count, then formats the mantissa via CreateFormatterObject + FormatNumericToString configured for fraction digits = digitCount - 1 (which sidesteps the 21 cap on the significant-digit slots). - RenderBigIntInExponentialNotation: takes a BigInt and rewrites it in canonical exponential form, absorbing trailing zeros into the exponent. Wires these through the constructor and convertTo so any String stored in [[AmountValue]] is already in canonical exponential form, and through toString so Number-backed values use Number.prototype.toExponential and BigInt-backed values use the new AO. Resolves the TODO left in #102.
Replaces the explicit StrDecimalLiteral parse + StringIntlMV dance with a single call to ToIntlMathematicalValue, which returns the same (value, digit count) pair and also resolves the NaN/Infinity special cases through its return value rather than by string comparison.
Co-authored-by: Eemeli Aro <eemeli@mozilla.com>
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The exponential-notation rendering of Amount values is the subject of PR #104. Per Richard Gibson's suggestion, this PR is narrowed to cover only the bracket-and-tilde serialization style. Reverts the exponential example values, the unit-name canonicalization (kg → kilogram), and the 'canonical exponential notation' wording in toString's description. Drops the spec algorithm's placeholder TODO line, since exponential normalization is fleshed out in PR #104.
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Resolves the toString TODO with a new AO,
RenderInExponentialNotation(value, sigDigits), which renders a mathematical value in canonical exponential notation.BigInt rendering here doesn't strip trailing zeros, so
100000nnow serializes as"1.00000e+5", which makes things uniform with howNumbersandStringsare handled.An editorial note records that the AO does essentially overlaps with
Number.prototype.toExponentialand that the two should eventually share an extracted operation.