sprintf formatting regression

Question

sprintf formatting regression

ray007 opened this issue 6 years ago · comments

Have you checked the guidelines in our Contributing document?

Description

After upgrading to the current version of sprintf.js, a formatter I'm using in my code does not work anymore.
The format string %.*f now results in "f" instead of a number with the precision taken from the argument list.

Rafał Kukawski · Answer 1 · Mon Mar 12 2018 19:45:20 GMT+0800 (China Standard Time)

In last patch I improved compatibility with PHP. The format you've used is not valid (per http://php.net/sprintf).
Previous sprintf implementation differed a lot from PHP's sprintf implementation.

Now a question to @kvz : what strategy should I follow? Keep backward compatibility with older locutus releases in mind or mimic PHP as close as possible?

ray007 · Answer 2 · Mon Mar 12 2018 23:00:46 GMT+0800 (China Standard Time)

Sounds like a bug in the php implementation to me. At least when looking at something like https://en.wikipedia.org/wiki/Printf_format_string#Precision_field

Kevin van Zonneveld · Answer 3 · Tue Mar 13 2018 16:47:58 GMT+0800 (China Standard Time)

As a rule of thumb, I would mimic php's behavior as close as possible (while still being useful in/with pure js projects/objects), and not worry about backwards compatibility. We're not semver, and can bundle a *BREAKING* into the CHANGELOG.md for that function, in that PR.

…

-- Kevin van Zonneveld (kvz.io) Co-founder at Transloadit (transloadit.com) Core-author of tus (tus.io)

On 12 March 2018 at 16:00:48, ray007 ***@***.***) wrote: Sounds like a bug in the php implementation to me. At least when looking at something like [https://en.wikipedia.org/wiki/Printf_format_string#Precision_field](https://en.wikipedia.org/wiki/Printf_format_string#Precision_field) -- You are receiving this because you were mentioned. Reply to this email directly or view it on GitHub: #365 (comment)

ray007 · Answer 4 · Tue Mar 13 2018 19:21:50 GMT+0800 (China Standard Time)

It's not just a breaking change, it's removing a feature.

Rafał Kukawski · Answer 5 · Tue Mar 13 2018 23:19:42 GMT+0800 (China Standard Time)

It's now a tough nut to crack, because restoring the feature means breaking PHP compability.
If we can call it a PHP bug? Not sure, it's maybe on purpose, because PHP's sprintf is not just a wrapper around the C-function. Here is the precision parsing, and here applying the precision. I don't see any logic which is derived from .* format

Rafał Kukawski · Answer 6 · Sat Mar 24 2018 21:30:30 GMT+0800 (China Standard Time)

My plan is to port the C version of sprintf in the C-lang namespace of locutus. Hope this solution suits you.

ray007 · Answer 7 · Mon Mar 26 2018 14:50:26 GMT+0800 (China Standard Time)

Sounds good to me. Thank you.
When you do so, could you please trigger this thread here with another comment?

Rafał Kukawski · Answer 8 · Sun Apr 01 2018 01:21:14 GMT+0800 (China Standard Time)

@ray007 I've prepared a pull request (#368) implementing sprintf.
I tried to be as close as possible to the rules you've linked previously.
The implementation is not yet 100% complete, but I'll extend the function with new patches.
Please check if it works as expected for you.

Rafał Kukawski · Answer 9 · Wed Aug 08 2018 03:26:02 GMT+0800 (China Standard Time)

I will close the issue. In case there are problems with the new implementation, please raise new tickets.

ray007 · Answer 10 · Wed Aug 08 2018 18:08:32 GMT+0800 (China Standard Time)

Thanks.
I haven't yet updated since my target environment is ES5 only, will hopefully find time soon...