[Indented syntax improvements] Dart implementation #2467

jamesnw · 2024-12-16T18:55:05Z

Blocked until proposal is accepted.

sass-spec [Indented syntax improvements] Specs sass-spec#2041

[skip sass-embedded]

…d-syntax-improvements

…vidually

…d-syntax-improvements

jamesnw · 2024-12-16T19:23:03Z

@nex3 This is ready for review. Here are some questions I wanted to flag as you review. Thanks!

allowNewlines is set to true in some cases, like in parser* functions or in scss.dart, where the value is non-impactful. Should this usage be differentiated somehow for clarity?
There are some places, like in _atRootQuery, where allowNewlines is true because it is inside parentheses. I opted to not use the _inParentheses variable except for one place where the consumption did rely on it, in _supportsCondition. Would it be more idiomatic to use _inParentheses, even if the consumption is in the same function?
In the + include syntax, I am not supporting whitespace after the + as it can be part of a selector. This differs from the = mixin syntax- should they be the same?
I added paren/bracket context to almostAnyValue, with the only change being that they must be matched. That means the error for a:has(d[)] will be changed from "Expected identifer" to "Expected ]". Since almostAnyValue is used for more than selectors, should I make this functionality opt-in, dependent on a parameter? Based on the places where this is used, I don't foresee issues with bracket matching, but want to verify.

…d-syntax-improvements

nex3

@nex3 This is ready for review. Here are some questions I wanted to flag as you review. Thanks!

allowNewlines is set to true in some cases, like in parser* functions or in scss.dart, where the value is non-impactful. Should this usage be differentiated somehow for clarity?

For classes where it's universally non-impactful, I'd define a local _whitespace() function that takes no arguments with a comment explaining that the value isn't relevant.

There are some places, like in _atRootQuery, where allowNewlines is true because it is inside parentheses. I opted to not use the _inParentheses variable except for one place where the consumption did rely on it, in _supportsCondition. Would it be more idiomatic to use _inParentheses, even if the consumption is in the same function?

I think how it is now is better.

In the + include syntax, I am not supporting whitespace after the + as it can be part of a selector. This differs from the = mixin syntax- should they be the same?

There's already an odd inconsistency here where whitespace is allowed after = but not after +, so I think it's fine to expand that to allowing newlines as well. It's possible that we should deprecate that, but it's not in-scope for this change.

I added paren/bracket context to almostAnyValue, with the only change being that they must be matched. That means the error for a:has(d[)] will be changed from "Expected identifer" to "Expected ]". Since almostAnyValue is used for more than selectors, should I make this functionality opt-in, dependent on a parameter? Based on the places where this is used, I don't foresee issues with bracket matching, but want to verify.

It's fine to change this error. Arguably the bracket error is clearer anyway.

nex3 · 2024-12-20T23:22:22Z

lib/src/parse/keyframe_selector.dart

@@ -15,7 +15,7 @@ class KeyframeSelectorParser extends Parser {
    return wrapSpanFormatException(() {
      var selectors = <String>[];
      do {
-        whitespace();
+        whitespace(allowNewlines: false);


There's no need to pass : false here, since this is neither a super nor subclass of SassParser.

nex3 · 2024-12-20T23:28:17Z

lib/src/parse/parser.dart

@@ -67,23 +67,29 @@ class Parser {
    if (!scanner.scanChar($dollar)) return false;
    if (!lookingAtIdentifier()) return false;
    identifier();
-    whitespace();
+    whitespace(allowNewlines: false);


It doesn't matter because this is only called from a static method, but in theory if this were used in the indented syntax I think we would want to allow newlines here because $foo\n isn't a complete Sass statement.

nex3 · 2024-12-20T23:28:46Z

lib/src/parse/parser.dart

    return scanner.scanChar($colon);
  }

  // ## Tokens

  /// Consumes whitespace, including any comments.
+  ///
+  /// If [allowNewlines] is true, the indented syntax will consume newlines as
+  /// whitespace, in positions when a statement can not end.


Nit:

Suggested change

/// whitespace, in positions when a statement can not end.

/// whitespace in positions when a statement can't end.

Also below.

nex3 · 2024-12-20T23:35:57Z

lib/src/parse/sass.dart

+  bool atEndOfStatement() {
+    var next = scanner.peekChar();
+    return next.isNewline ||
+        next == null ||


I think it would be less confusing to put next == null first, even if next.isNewline handles nulls gracefully.

nex3 · 2024-12-20T23:36:27Z

lib/src/parse/sass.dart

+    var next = scanner.peekChar();
+    return next.isNewline ||
+        next == null ||
+        (next == $semicolon && scanner.peekChar(1).isNewline);


I think we should treat ; even without a newline as the end of a statement, and just let the parser throw an error when it encounters more text afterwards.

nex3 · 2024-12-23T23:31:08Z

lib/src/parse/stylesheet.dart

+          allowNewlines: allowNewlines ||
+              bracketList ||
+              _inParentheses ||
+              wasInExpression);


Why does this trigger on wasInExpression?

nex3 · 2024-12-23T23:41:44Z

lib/src/parse/stylesheet.dart

+          brackets.add(opposite(bracket));
+
+        case $rparen || $rbracket:
+          if (brackets.isEmpty) break loop;


Given that we're now explicitly parsing matching brackets here, it's probably best to throw a meaningful error here.

Note that this is technically a breaking change whether or not we throw an error here: [foo#{"]:is(bar"}) {x: y} is currently valid, but will become an error here. I think it's vanishingly unlikely that anyone is doing that, though, so it should be fine to break, but we should add a "potentially breaking bug fix" note in the changelog about it.

nex3 · 2024-12-23T23:45:19Z

lib/src/parse/stylesheet.dart

@@ -2943,7 +2999,7 @@ abstract class StylesheetParser extends Parser {
        case $space || $tab:
          buffer.writeCharCode(scanner.readChar());

-        case $lf || $cr || $ff when indented:
+        case $lf || $cr || $ff when indented && !allowNewlines:


Shouldn't this also allow newlines when brackets isn't empty?

nex3 · 2024-12-23T23:46:31Z

lib/src/parse/stylesheet.dart

      var right = _supportsConditionInParens();
      condition = SupportsOperation(
          condition, right, operator, scanner.spanFrom(start));
-      whitespace();
+      whitespace(allowNewlines: false);


Should this be : inParentheses?

nex3 · 2024-12-23T23:47:24Z

lib/src/parse/stylesheet.dart

    var start = scanner.state;
    if (scanIdentifier("not")) {
-      whitespace();
+      whitespace(allowNewlines: true);


I think we should only allow newlines here when inParentheses is true, since we want to eventually treat @supports like any other at-rule. Same below.

jamesnw added 30 commits November 1, 2024 14:59

Support optional semicolons at the end of indented lines

2c4a054

Merge branch 'main' of https://github.com/sass/dart-sass into indente…

94f8c11

…d-syntax-improvements

Add comment, update error message

4d0e43c

Handle each

dc12326

Allow whitespace in @for, handle initial whitespace for at-rules indi…

332ca09

…vidually

@content, @extend newlines

3715ee4

@input newlines

8594fe5

Whitespace for @mixin, @include

512304b

Whitespace in @media, @-moz-document, @supports

c09e506

Whitespace in @use and @forward

1fa6ccf

Whitespace in @function and @return

9e49c3b

Whitespace in @if

939d2fa

Whitespace in @while

d050c01

Whitespace in @at-root

e8cf0fb

Merge branch 'main' into indented-syntax-improvements

b6c801a

Whitespace in arguments and @charset

0aaa63a

+ and = syntax whitespace

cfa30ee

Whitespace in variable declarations

e6442d4

Move initial whitespace inside each at rule

0d81850

Whitespace in lists and maps

2a3c160

Handle whitespace in important and unaries

65ec459

Whitespace in interpolation, unblock expressionUntilComma issues

7de5da3

Consume whitespace in sub-stylesheet parsers

85d14a9

Merge branch 'main' of https://github.com/sass/dart-sass into indente…

dac97ed

…d-syntax-improvements

Consume whitespace in parse/css. Meaningless, as it extends scss

61304e6

Whitespace in @supports

d7ee188

Whitespace in @media

976e38a

Handle whitespace in arg invocations

a7f439c

Whitespace in parsers

14dbd8d

Allow newlines in comments

c552cdd

jamesnw added 10 commits December 13, 2024 10:42

Newlines in selector parse

adc94db

Require whitespace argument

114cfa6

Allow whitespace inside url parens

7e58b2d

Cleanup

78bd20f

Merge branch 'main' of https://github.com/sass/dart-sass into indente…

afdd5ec

…d-syntax-improvements

Handle newlines in parentheses in supports conditions

13c42b2

Allow newlines in brackets and parens in selectors

61b4137

Documentation, review

0843edd

More docs

5e880e3

Rename consumeNewlines to allowNewlines

1ec13e5

jamesnw mentioned this pull request Dec 16, 2024

[Indented syntax improvements] Specs sass/sass-spec#2041

Open

1 task

jamesnw mentioned this pull request Dec 17, 2024

Indented syntax improvements oddbird/dart-sass#2

Closed

jamesnw added 2 commits December 17, 2024 12:11

Fix bug in semicolons in sass

5e3db80

Merge branch 'main' of https://github.com/sass/dart-sass into indente…

08747a9

…d-syntax-improvements

jamesnw mentioned this pull request Dec 17, 2024

Bump dart_style from 2.3.7 to 3.0.0 #2459

Merged

Merge branch 'main' of https://github.com/sass/dart-sass into indente…

38e05bf

…d-syntax-improvements

nex3 requested changes Dec 23, 2024

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[Indented syntax improvements] Dart implementation #2467

[Indented syntax improvements] Dart implementation #2467

jamesnw commented Dec 16, 2024 •

edited

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	/// whitespace, in positions when a statement can not end.
	/// whitespace in positions when a statement can't end.

[Indented syntax improvements] Dart implementation #2467

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[Indented syntax improvements] Dart implementation #2467

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jamesnw commented Dec 16, 2024 • edited Loading

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jamesnw commented Dec 16, 2024 •

edited

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