Re: ICU - NumberFormatter::ROUNDING_MODE default ROUND_HALFEVEN

On 8/3/23 13:55, Hans Krentel via internals wrote:

This is a proposal to consider to discuss/change the default value of

     NumberFormatter::ROUNDING_MODE

from current

     NumberFormatter::ROUND_HALFEVEN

to

     NumberFormatter::ROUND_HALFUP

. I got the attention of this from an unrelated user in an online forum (SO) and also checked with MDN which has it as default as well. [1] If I'm not mistaken, ROUND_HALFUP is the rounding with number_format() and the default rounding mode with round(). Feedback from actual ICU caretakers would be good though, because me is entirely from a users perspective, also I know how to change attributes to non default values, this is not a programming question I have. I hope you don't mind the attention to detail. Best -- hakre [1]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/NumberFormat/NumberFormat#roundingmode

The default rounding mode in ICU for the number formatter appears to be "half even," and that's probably why it's the default in PHP. See: - https://unicode-org.github.io/icu/userguide/format_parse/numbers/rounding-modes#half-even - https://unicode-org.github.io/icu-docs/apidoc/released/icu4c/classicu_1_1number_1_1NumberFormatterSettings.html#aceb7d34843e0d44e138fb3f43c98db32 The MDN documentation you linked to describes the JavaScript implementation of ECMA-402, which differs from ICU in a number of ways. One of which is in the default rounding mode for Intl.NumberFormat, which is not the same as ICU's NumberFormatter (even though most ECMA-402 implementations use icu4c internally). Here's where ECMA-402 defines halfExpand as the default for roundingMode (see step 10 under section 15.1.3): https://tc39.es/ecma402/#sec-setnfdigitoptions Since PHP's intl extension follows icu4c and not ECMA-402, I think it makes sense for it to continue to use the same default values as icu4c. Cheers, Ben

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