From 648dc04c33bc463238495a5ace55dc8ed5f55c74 Mon Sep 17 00:00:00 2001
From: ConnorSkees <39542938+ConnorSkees@users.noreply.github.com>
Date: Mon, 6 Apr 2020 13:13:03 -0400
Subject: [PATCH] initial implementation of @ at-root

---
 src/atrule/mod.rs   | 37 +++++++++++++++++++++++++++++++++++--
 src/lib.rs          |  5 ++++-
 src/output.rs       |  4 ++++
 src/selector/mod.rs |  7 ++-----
 tests/at-root.rs    |  5 +++++
 5 files changed, 50 insertions(+), 8 deletions(-)

diff --git a/src/atrule/mod.rs b/src/atrule/mod.rs
index 6323469..d14fdc0 100644
--- a/src/atrule/mod.rs
+++ b/src/atrule/mod.rs
@@ -9,7 +9,7 @@ use crate::utils::{
     read_until_semicolon_or_closing_curly_brace,
 };
 use crate::value::Value;
-use crate::{Stmt, Token};
+use crate::{RuleSet, Stmt, Token};
 
 pub(crate) use function::Function;
 pub(crate) use if_rule::If;
@@ -40,6 +40,7 @@ pub(crate) enum AtRule {
     Each(Vec<Stmt>),
     While(Vec<Stmt>),
     If(If),
+    AtRoot(Vec<Stmt>),
 }
 
 impl AtRule {
@@ -103,7 +104,39 @@ impl AtRule {
             }
             AtRuleKind::Use => todo!("@use not yet implemented"),
             AtRuleKind::Annotation => todo!("@annotation not yet implemented"),
-            AtRuleKind::AtRoot => todo!("@at-root not yet implemented"),
+            AtRuleKind::AtRoot => {
+                let selector = &Selector::replace(
+                    super_selector.clone(),
+                    Selector::from_tokens(
+                        &mut read_until_open_curly_brace(toks).into_iter().peekable(),
+                        scope,
+                        super_selector,
+                    )?,
+                );
+                toks.next();
+                devour_whitespace(toks);
+                let mut body = read_until_closing_curly_brace(toks);
+                body.push(toks.next().unwrap());
+                devour_whitespace(toks);
+                let mut styles = Vec::new();
+                let raw_stmts = eat_stmts(&mut body.into_iter().peekable(), scope, &selector)?
+                    .into_iter()
+                    .filter_map(|s| match s {
+                        Stmt::Style(..) => {
+                            styles.push(s);
+                            None
+                        }
+                        _ => Some(s),
+                    })
+                    .collect::<Vec<Stmt>>();
+                let mut stmts = vec![Stmt::RuleSet(RuleSet {
+                    selector: selector.clone(),
+                    rules: styles,
+                    super_selector: Selector::new(),
+                })];
+                stmts.extend(raw_stmts);
+                AtRule::AtRoot(stmts)
+            }
             AtRuleKind::Charset => {
                 read_until_semicolon_or_closing_curly_brace(toks);
                 if toks.peek().unwrap().kind == ';' {
diff --git a/src/lib.rs b/src/lib.rs
index d061401..cee1028 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -382,6 +382,7 @@ impl<'a> StyleSheetParser<'a> {
                                     AtRule::If(i) => {
                                         rules.extend(i.eval(&mut Scope::new(), &Selector::new())?);
                                     }
+                                    AtRule::AtRoot(root_rules) => rules.extend(root_rules),
                                     u @ AtRule::Unknown(..) => rules.push(Stmt::AtRule(u)),
                                 }
                             }
@@ -416,6 +417,7 @@ impl<'a> StyleSheetParser<'a> {
                         return Err("@content is only allowed within mixin declarations.".into())
                     }
                     AtRule::Return(..) => return Err("This at-rule is not allowed here.".into()),
+                    AtRule::AtRoot(root_stmts) => stmts.extend(root_stmts),
                     r => stmts.push(Stmt::AtRule(r)),
                 },
                 Expr::Styles(s) => stmts.extend(s.into_iter().map(Box::new).map(Stmt::Style)),
@@ -463,7 +465,7 @@ pub(crate) fn eat_expr<I: Iterator<Item = Token>>(
 ) -> SassResult<Option<Expr>> {
     let mut values = Vec::with_capacity(5);
     while let Some(tok) = toks.peek() {
-        match &tok.kind {
+        match tok.kind {
             ':' => {
                 let tok = toks.next();
                 if devour_whitespace(toks) {
@@ -600,6 +602,7 @@ pub(crate) fn eat_expr<I: Iterator<Item = Token>>(
                             f @ AtRule::While(..) => Ok(Some(Expr::AtRule(f))),
                             f @ AtRule::Each(..) => Ok(Some(Expr::AtRule(f))),
                             u @ AtRule::Unknown(..) => Ok(Some(Expr::AtRule(u))),
+                            u @ AtRule::AtRoot(..) => Ok(Some(Expr::AtRule(u))),
                         };
                     }
                 }
diff --git a/src/output.rs b/src/output.rs
index 997052b..76912a4 100644
--- a/src/output.rs
+++ b/src/output.rs
@@ -89,6 +89,10 @@ impl Css {
                             .get_mut(0)
                             .expect("expected block to exist")
                             .push_comment(s),
+                        Stmt::AtRule(AtRule::AtRoot(stmts)) => stmts
+                            .into_iter()
+                            .map(|r| Ok(vals.extend(self.parse_stmt(r)?)))
+                            .collect::<SassResult<()>>()?,
                         Stmt::AtRule(r) => vals.push(Toplevel::AtRule(r)),
                     };
                 }
diff --git a/src/selector/mod.rs b/src/selector/mod.rs
index 7773951..4c67e59 100644
--- a/src/selector/mod.rs
+++ b/src/selector/mod.rs
@@ -384,13 +384,10 @@ impl Selector {
         }
     }
 
-    fn replace(super_selector: Selector, this: Selector) -> Selector {
-        if super_selector.0.is_empty() {
+    pub fn replace(super_selector: Selector, this: Selector) -> Selector {
+        if super_selector.0.is_empty() || this.0.is_empty() {
             return this;
         }
-        if this.0.is_empty() {
-            return super_selector;
-        }
         let mut parts = Vec::with_capacity(super_selector.0.len());
         for (idx, part) in super_selector.clone().0.into_iter().enumerate() {
             let mut found_inner = false;
diff --git a/tests/at-root.rs b/tests/at-root.rs
index 6d49d3d..3aeb444 100644
--- a/tests/at-root.rs
+++ b/tests/at-root.rs
@@ -28,3 +28,8 @@ test!(
     ".foo {\n  @at-root & {\n    .bar {\n      @at-root & {\n        a: b;\n      }\n    }\n  }\n}\n",
     ".foo .bar {\n  a: b;\n}\n"
 );
+test!(
+    deeply_nested_with_rulesets_and_styles,
+    ".foo {\n  @at-root .bar {\n    a: b;\n    c {\n      d: e;\n      foo {\n        bar: baz;\n      }\n      h: j;\n    }\n    f: g;\n  }\n}\n",
+    ".bar {\n  a: b;\n  f: g;\n}\n.bar c {\n  d: e;\n  h: j;\n}\n.bar c foo {\n  bar: baz;\n}\n"
+);