RE: Bug in grammar for paths

Albeit it's a bit tricky to parse it with Javascript it's not impossible.
If you search for an example implementation just take a look into
pathArrays of svg.js.


Am 30.04.2017 00:16 schrieb "David Dailey" <ddailey@zoominternet.net>:

> Hi Amelia, all,
>
>
>
> Yeah, the output from Illustrator, for example, tends to be gnarly and not
> easily parsed by JavaScript. It would have been nice if the syntax had been
> a bit easier, since a static collection of paths is not always the end
> result, nor the most accessible (for search engines, screen readers, and
> communities downstream).
>
>
>
> Cheers
>
> D
>
>
>
> *From:* Amelia Bellamy-Royds [mailto:amelia.bellamy.royds@gmail.com]
> *Sent:* Saturday, April 29, 2017 3:15 PM
> *To:* Jirka Kosek
> *Cc:* Paul LeBeau; www-svg
> *Subject:* Re: Bug in grammar for paths
>
>
>
> These quirks of the path grammar are used by SVG minimizers/optimizers, so
> they can't be changed now.  Content relies on the fact that 4-3.1.3e2.4 is
> four separate numbers (equivalent to 4, -3.1, 0.3e2, 0.4).
>
>
>
> Yes, it does require a more complex parser.  You can't just split the
> string on separators, you need to scan through it character by character,
> matching the sequence as defined, using a greedy algorithm.  A number is as
> many characters as make sense in a number, in order, and no more.
>
>
>
> Jirka Kosek wrote:
>
> Seems that grammar is only illustrational because there are other issues
> with it -- for example grammar accepts only integers not decimal numbers.
>
>
>
> This was an error from when SVG 2 was edited to add the Bearing command
> and convert from BNF to EBNF.  There is an open issue, I didn't realize
> that it never got fixed:  https://github.com/w3c/svgwg/issues/286
>
>
>
> The SVG 1.1 definition of a "number" is correct (
> https://www.w3.org/TR/SVG11/paths.html#PathDataBNF). Decimals and
> scientific notation are allowed.
>
>
>
> If anyone wants to make a pull request on SVG 2 to fix it, that would be
> appreciated. We can at least change it in the Editor's Draft, although I
> don't know when the TR spec will be re-published.
>
>
>
> ~ABR
>