- From: Guillaume via GitHub <sysbot+gh@w3.org>
- Date: Wed, 19 Mar 2025 15:22:32 +0000
- To: public-css-archive@w3.org
cdoublev has just created a new issue for https://github.com/w3c/csswg-drafts:
== [css-syntax-3] Should forgiving grammars allow bad tokens? ==
In [#11315](https://github.com/w3c/csswg-drafts/issues/11315#issuecomment-2567598772), I touched on bad tokens in declaration values defined with forgiving grammars. Browsers handle them differently.
Bad tokens are `<bad-string-token>`, `<bad-url-token>`, and orphan `)`, `]`, `}`. Per a non-normative note in CSS Syntax, they are always parse errors but are preserved in the token stream to define fine-grained error-handling in some places like the prelude of `@media`.
Indeed, some rule preludes are defined with forgiving grammars.
At the top level, `@media } {}` is interpreted as `@media not all {}`. Nested, it is invalid and ignored: `style { @media } {}`. Is this difference a problem?
Browsers also interpret `:is(}) {}` differently.
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I do not see the usefulness of allowing bad tokens in forgiving grammars. Would it be a problem to make them invalid in forgiving grammars?
Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/11966 using your GitHub account
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Received on Wednesday, 19 March 2025 15:22:33 UTC