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postcss / postcss-selector-parser

A CSS selector parser, integrates with postcss but does not require it.
MIT License
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invalid/non stable ast for combinator with comment #189

Open alexander-akait opened 5 years ago

alexander-akait commented 5 years ago

Input:

h2 /*test*/ h4 { } /* Here we don't have `comment` node in ast (store comment in `raws`) */
h2/*test*/h4 { } /* Comment in ast */

It is do impossible analyzes comments, also adopt new version to stylelint and prettier. For me it is bug, but fixing this change ast.

alexander-akait commented 5 years ago

/cc @ai what do you think about this

ai commented 5 years ago

Why it will change AST?

alexander-akait commented 5 years ago

@ai new comment node appears in ast(before it was in raws), just want to clarify should we release this as patch or major?

ai commented 5 years ago

Technically it should be major

alexander-akait commented 5 years ago

Same problem for [ /*t*/ title /*t*/ = /*t*/ "Something" /*t*/ ], comments should be part of ast not raw

alexander-akait commented 5 years ago

/cc @ai i ahve some questions about spaces too Example:

[   href   =   "test"   i   ] { }
  ^      ^   ^        ^   ^

What node(s) should store spaces in this case (inside raws?)? Because now logic in parser is very misleading and I can't understand whether we do it right or not. We have attribute, value, insensitive values.

ai commented 5 years ago

To be honest, I am not sure that I know the best answer.

But I think in selector parser we should work with spaces in a different way, compare to PostCSS core. In main CSS syntax, whitespaces don’t mean anything. In selector, whitespace can have a lot of meanings.

So, I think it could be better to have a special token for spaces.

alexander-akait commented 5 years ago

@ai yep, we already have special token for space, my questions about where we should store meta information about space (raws). Let's see on example above:

ai commented 5 years ago

Why do we need a raws for whitespaces when we have space token?

alexander-akait commented 5 years ago

@ai hm can you provide example/PoC of ast with space token (based on example above)? We need this spaces for linting/printing in stylelint and prettier

ai commented 5 years ago

a b > { type: "word", value: "a" }, { type: "space", value: " " }, { type: "word", value: "b" }

alexander-akait commented 5 years ago

@ai in example above space is descendant selector, we already provide combinator as separate node, but in my example spaces mean nothing so we omit them from ast

ai commented 5 years ago

I am not sure that we should omit them from AST.

alexander-akait commented 5 years ago

@ai I do not see their meaning as they really do not carry here any semantic load, also we do this right now, we can plan this on next major, but will be great solve problems with spaces using raws for next release

ai commented 5 years ago

Yeap. This discussion is on you. Sorry, that I can't help right now.

alexander-akait commented 5 years ago

@ai Maybe not related to issue, but what is blocker integrate selector parser in postcss? Non standard syntax? Or nobody send a PR?

ai commented 5 years ago

@evilebottnawi I am afraid that we will freeze API which will not be the best.

alexander-akait commented 5 years ago

@ai we can afraid this forever :smile: To be honestly ast of postcss is not enough for prettier/stylelint nowadays (prettier breaks code in many cases and i recommended don't use this for css/scss/less/etc). I think we should start integration selector/value/media parsers otherwise we will need do fork postcss and continue development :disappointed:

alexander-akait commented 5 years ago

Also we can release this under flag/option and as experimental (adding information to readme about non stable)

We have big tests code base in stylelint and prettier and webpack so i think we catch all problems very fast

ai commented 5 years ago

RIght now our main focus is visitor API https://github.com/postcss/postcss/pull/1245

alexander-akait commented 5 years ago

Great feature :+1: Already look on this.

@ai Is there any sense send a PR or better fork postcss and starting own development for prettier? Because i don't want to waste my time on something what will be never merged.

ai commented 5 years ago

@evilebottnawi I have a better plan. Let’s release new AST in postcss-selector-parser and if nobody will complain about it, we can move it to PostCSS

alexander-akait commented 5 years ago

@ai okay :+1: i will ping you before release or when i have some questions