RFC Blogpost for indented syntax (sass#1260)

source/blog/044-rfc-indented-syntax.md

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+---
+title: "Request for Comments: Indented Syntax Improvements"
+author: James Stuckey Weber
+date: 2024-12-03 15:30:00 -8
+---
+
+For users of the indented syntax (`.sass`), there has been a long standing
+request for the ability to have line breaks that don't end a statement. Certain
+CSS syntaxes like `grid-template` and `@font-face` `src` declarations are long,
+and line breaks can greatly increase the readability of the styles. 
+
+There have been many suggestions, several attempts, and numerous workarounds to
+address this pain point. We are proposing several new syntax options in the
+indented syntax that add considerable flexibility and look to address this as
+part of the language.
+
+## Multiline statements
+
+We propose allowing statements in the indented syntax to span multiple lines, as
+long as line breaks occur in places where the statement can't end. 
+
+A common way of using this syntax will be wrapping lists with line breaks in
+parentheses. This allows for a grid-template declaration on multiple lines.
+
+```sass
+.grid
+  display: grid
+  grid-template: (
+    "header" min-content
+    "main" 1fr
+  )
+}
+```
+
+As usual, these parentheses will not be included in the output.
+
+```css
+.grid {
+  display: grid;
+  grid-template: "header" min-content "main" 1fr;
+}
+```
+
+Powering this change is the underlying rule that linebreaks only end statements
+where it's valid for a statement to end. Anywhere where a statement can't end, a
+linebreak is ignored. This means that if the parser can't tell whether or not a
+linebreak is intended to end a statement, it will end the statement.
+
+This example demonstrates several places where line breaks will not end
+statements.
+
+```sass
+@each $item in /* A statement can't end after the word "in" in an `@each` statement. */
+    1, 2, 3
+  .item-#{ 
+    $item /* A statement can't end inside the curly braces in an interpolation. */
+  }
+    content: $item * /* A statement can't end after a multiplication operator. */
+        10
+```
+
+
+As a counter example, here are some places in the same stylesheet where
+linebreaks could end statements. These linebreaks will cause compilation errors
+because the _next_ line is not able to be parsed.
+
+> **Important! This code snippet demonstrates what will NOT work.**
+
+```sass
+@each $item in 1, /* A statement can end after a value, even in the middle of a list. */
+     2, 3
+  .item-#{ $item }
+    content: $item /* A statement can end after a value, and does not look ahead for operators. */
+      * 10
+```
+
+## SCSS-in-Sass
+
+We are also proposing a new block-level opt-in to the SCSS format. One 
+workaround for not having multiline statements has been to author some styles in
+separate SCSS files, and this provides an inline alternative.
+
+To opt in to the SCSS format for a block, you simply need
+to wrap the block inside of curly braces. 
+
+```sass
+a
+  color: blue
+
+// Opt in to SCSS format for this rule
+p {
+  padding: 
+    var(--top-padding, 1em)
+    var(--right-padding, 2em)
+    var(--bottom-padding, 1em)
+    var(--left-padding, 1.5em);
+  color: red;
+}
+
+// Back to indented syntax
+strong
+  font:
+    weight: bold
+```
+
+## Semicolons are also allowed
+
+Another proposed change would allow semicolons to optionally be added at the end
+of statements in the indented syntax. Indentation rules still apply, so you
+won't be able to separate multiple statements on the same line, even with a
+semicolon (unless you're in a [SCSS-in-Sass](#scss-in-sass) block).
+
+## No breaking changes
+
+These changes are opt-in, and authors who don't want to use the new syntax do
+not have to. No changes need to be made to existing stylesheets written in the
+indented syntax.
+
+## Next steps
+
+This is still in the proposal phase, and we are open to feedback. Review the
+proposal [on Github], and [open an issue] with any thoughts or concerns you
+may have.
+
+[on Github]: https://github.com/sass/sass/blob/main/proposal/indented-syntax-improvements.md
+[open an issue]: https://github.com/sass/sass/issues/new
+
+In addition to feedback from authors using the indented syntax, we are also
+interested in hearing from maintainers of tooling that supports the indented
+syntax.