Use minus sign instead of hyphen-minus by default? about d3-format

[mbostock]

(This post was cross-posted to the Observable forum.)

D3 did use the minus sign originally, but people complained about that, too (e.g., #595), primarily because there was an expectation that d3.format would use the same symbol as JavaScript’s number.toString. The minus sign was thus replaced with hyphen-minus in 2.10.0 (da3131c, #756).

I’m somewhat ambivalent. Both are technically correct. I’m aware that hyphen-minus is a compromise from a time where good typesetting was largely impractical for computers. As I commented on the linked issue, I don’t think it’s reasonable to expect d3.format to be compatible with JavaScript’s number coercion, since the goal of d3.format is to format numbers for human consumption instead of machines.

At any rate, we should at least allow you to override the minus sign in the locale, and perhaps it is worth reverting the adoption of hyphen-minus.

[mbostock]

This is now available as an opt-in by specifying the locale’s minus property. And I’m considering making the minus sign the default (again) in the next major version.

[kirkpsmith]

I came here through Altair->vega-lite->vega, asking the same question. Some more details from my post which may help:

When displaying negative numbers, use a minus sign − (unicode 2212) instead of a hyphen -. There could be an option (like this one in matplotlib) to specify either option (but defaulting to the minus sign would be optimal).

In IDLE, you can see the difference between a true minus sign and a hyphen with this:
print(u'f\u2212f\nf\u002Df')
or
print(u'f\u2212f\nf-f')

Reference: Unicode for "hyphens"