The TAU constant.

[DartBot]

This issue was originally filed by @si-robertson

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This is a small request for the TAU constant to be added to the math.dart library.

  /**
   * The TAU constant.
   */
  const double TAU = 6.2831853071795864;

I'm sure most of the Dart team will understand why this would be useful :)

[DartBot]

This comment was originally written by @mezoni

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I agree too.
The following constants also should be added:

E = 2.71828182845904523536028747135266250 // Neper number
SQRT_2 = 1,41421356237309504880168872420969808
SQRT_3 = 1,73205080756887729352744634150587237
PHI = 1,61803398874989484820458683436563812 // Golden ratio

[lrhn]

Added Library-Math, Area-Library, Triaged labels.

[lrhn]

Another options is to have the values as static constants on the double class.
That would avoid adding top-level constants that may conflict with existing constants in other libraries.

[floitschG]

Closing this bug as duplicate of issue #4.

Wrt comment #­2, we already have: E and SQRT2.
Please open new bugs for PHI and SQRT3, if you think they should be added.

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Added Duplicate label.
Marked as being merged into #14.

[DartBot]

This comment was originally written by @si-robertson

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I'm not sure merging this request with a 32 month old "WontFix" bug was the best thing to do because this request has more or less been flatlined as a result. The TAU constant is still being requested so I believe reconsideration by the Dart team is warranted at this time.

[lrhn]

The arguments used to close the request the first time are still valid.

Filing a new issue for the same change won't change that - this is a duplicate of issue #14.

A solution would be to add a package, e.g., "math_constants", with all the constants you can think of. They don't have to be in dart:math.

The expression (2.0*PI) is a compile-time constant in Dart, so there should be no performance penalty.

[DartBot]

This comment was originally written by @si-robertson

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I didn't say this request wasn't a duplicate, I said the Dart team should reconsider the request for TAU seeing as it's still being requested almost three years later. I wasn't even aware of issue #14 until this request was merged with it.

If the Dart team is refusing to add this due to possible conflicts with user created libraries then that excuse also blocks any new APIs from being added to Dart in the future, right? What happens if someone has a FileLoader class in their library and the W3C one day decide to add a class with the same name to the standard JavaScript File API, how are the Dart team doing to handle that without breaking existing code.

E, LN10, LOG2E, PI and all the others are also compile-time constants.

[floitschG]

The need for E, LN10, ... is higher than for Tau. While I remember how to get to Tau (= 2PI) I don't remember the values for E, LN10, ...
Furthermore, 2PI doesn't even lose in precision (because it's just a multiplication by two which is a trivial increment of the exponent in binary floating-point representation).

Finally: http://www.thepimanifesto.com/