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  • Prioritized list of Decimal method additions

Prioritized list of Decimal method additions

# Sam Ruby (17 years ago)

Previous discussions focused on operators and type/membership related builtin functions (i.e., typeof and instanceof). Here's a prioritized list of functions provided by IEEE 754-2008 and/or the decNumber implementation.

The actual number of "a" and "a-" methods is fairly small, particularly once you remove ones that are available in ECMAScript via other means.

Absolute requirement, and must be implemented as an 'instance' method (for most of the others, the difference between a 'static' and 'instance' method is negotiable):

  • a toString

Available as prefix or infix operators, or as builtin functions, may not need to be duplicated as named Decimal methods:

  • a add
  • a compare
  • a copy
  • a copyNegate
  • a divide
  • a isFinite
  • a isNaN
  • a multiply
  • a remainder
  • a subtract

Essential 754, not available as infix operator, so must be made available as a named method. For consistency with Math, abs, max, and min should be 'static' methods:

  • a quantize
  • a copyAbs [called abs]
  • a max
  • a min

Very useful functions which are not in 754 for various reasons; strongly recommend include:

  • a- divideInteger [extremely handy]
  • a- digits [= significant digits]
  • a- reduce [often asked for]
  • a- toEngString [really handy in practice]
  • a- getExponent [esp. if no compareTotal]

Other 754 operations that are less essential but would probably add later anyway. 'b+' are a subset that are especially useful in practice:

  • b FMA
  • b canonical
  • b compareSignal
  • b+ compareTotal
  • b compareTotalMag
  • b copySign
  • b isCanonical
  • b+ isInfinite
  • b+ isInteger
  • b isNormal
  • b+ isSignaling [if sNaNs supported]
  • b+ isSignalling [" " "]
  • b+ isSigned
  • b isSubnormal
  • b+ isZero
  • b logB
  • b maxMag
  • b minMag
  • b nextMinus
  • b nextPlus
  • b radix
  • b remainderNear
  • b+ sameQuantum
  • b scaleB
  • b+ setExponent
  • b toInt32
  • b toInt32Exact
  • b+ toIntegralExact [perhaps only one of these]
  • b+ toIntegralValue [" " " " "]
  • b toUInt32
  • b toUInt32Exact

Probably drop because conflict with ES bitwise logical ops:

  • c and (as digitAnd)
  • c invert (as digitInvert)
  • c or (as digitOr)
  • c rotate
  • c shift
  • c xor (as digitXor)

And, finally, not needed:

(The first two of these are 754 but don't fit with ES)

  • class

  • classString

  • fromBCD

  • fromInt32

  • fromNumber

  • fromPacked

  • fromPackedChecked

  • fromString

  • fromUInt32

  • fromWide

  • getCoefficient

  • setCoefficient
  • d nextToward
  • show

  • toBCD

  • toNumber

  • toPacked

  • toWider

  • version

  • zero
  • Sam Ruby
# Sam Ruby (17 years ago)

Sam Ruby wrote:

Previous discussions focused on operators and type/membership related builtin functions (i.e., typeof and instanceof). Here's a prioritized list of functions provided by IEEE 754-2008 and/or the decNumber implementation.

The actual number of "a" and "a-" methods is fairly small, particularly once you remove ones that are available in ECMAScript via other means.

Updated test results including these methods can be found here:

intertwingly.net/stories/2008/09/20/estest.html

  • Sam Ruby