Warn when the `style` attribute is missing a semicolon `;`

[carson-katri]

A common mistake is writing a style attribute with spaces as delimiters instead of semicolons ;:

<Element style="padding() background(.red)" />

This should log a warning, ideally pointing to the position where the semicolon should be inserted. A message similar to this could be used:

Missing semicolon between modifiers in `style` attribute:

<Element style="padding() background(.red)" />
                         ^ add a `;` semicolon after `padding()`

home_live.swiftui.neex:1:25

Alternatively, spaces could be allowed as a delimiter as well or instead of semicolons.

[bcardarella]

I just compared to web and in Chrome I don't see any support for whitespace deliminator between style rules so I'd like to not support that in ours.

But I agree some warning would be nice. @NduatiK I think we'd need to support that in the parser itself as currently I'm just doing String.split(style, ";")

[NduatiK]

Let's clarify:

• you want a warning when the parser finds rules that are only delimited by whitespaces
• the warning should only happen inside style attributes
• warnings should be configurable from the caller, enabled on styles, disabled everywhere else (sheets)

@bcardarella, did I get that right?

[bcardarella]

so currently I split the value of the style attr on ; and just iterate through each rule one by one and send it to the parser. What I think we should do instead is send the entire string to the parser. The current RULES parser is splitting on newline, but we should probably introduce the optional ; to deliminate between rules:

padding(); background(.red)

should be the same as:

padding(); background(.red);

and

padding()
background(.red)

and

padding();
background(.red);

Does that make sense?

[NduatiK]

Makes sense.
One more clarification, would a missing semicolon be expected on sheets and produce a warning?

[bcardarella]

are you asking if the following:

padding();
fooBar()
barBaz();

where the 2nd rule has no semicolor?

[NduatiK]

Yes, should the SHEET sigil produce a warning if the 2nd rule's semicolon is missing?

I'd like to know if warnings should always be produced or if it should be configurable.

[bcardarella]

That's a good question, are semicolons required for multiline in css or not? I forget what the current state of that is. If it is then we should probably just follow that but it may need to be a v0.4 thing and accept the breaking change

[cmnstmntmn]

Going to link this issue liveview-native/liveview-client-swiftui#1421, since they might use the same parser internally.