From 5299bb0f97e32bbe9f8c76d709bc9c19c46a328b Mon Sep 17 00:00:00 2001
From: Linus Eriksson <Ben3eeE@users.noreply.github.com>
Date: Thu, 18 Oct 2018 18:13:00 +0200
Subject: [PATCH] Simplify syntaxTreeScopeDescriptorForPosition

---
 src/tree-sitter-language-mode.js | 52 +++++++++-----------------------
 1 file changed, 15 insertions(+), 37 deletions(-)

diff --git a/src/tree-sitter-language-mode.js b/src/tree-sitter-language-mode.js
index 5422a0714..fc87f16ac 100644
--- a/src/tree-sitter-language-mode.js
+++ b/src/tree-sitter-language-mode.js
@@ -430,42 +430,27 @@ class TreeSitterLanguageMode {
   }
 
   syntaxTreeScopeDescriptorForPosition (point) {
-    if (!this.tree) return this.rootScopeDescriptor
+    const nodes = []
     point = Point.fromObject(point)
-
-    const iterators = []
     this._forEachTreeWithRange(new Range(point, point), tree => {
-      const rootStartIndex = tree.rootNode.startIndex
       let node = tree.rootNode.descendantForPosition(point)
-
-      // Don't include anonymous token types like '(' because they prevent scope chains
-      // from being parsed as CSS selectors by the `slick` parser. Other css selector
-      // parsers like `postcss-selector-parser` do allow arbitrary quoted strings in
-      // selectors.
-      if (!node.isNamed) node = node.parent
-      iterators.push({node, rootStartIndex})
+      while (node) {
+        nodes.push(node)
+        node = node.parent
+      }
     })
 
-    iterators.sort(compareScopeDescriptorIterators)
-    const scopes = []
+    // The nodes are mostly already sorted from smallest to largest,
+    // but for files with multiple syntax trees (e.g. ERB), each tree's
+    // nodes are separate. Sort the nodes from largest to smallest.
+    nodes.reverse()
+    nodes.sort((a, b) =>
+      a.startIndex - b.startIndex || b.endIndex - a.endIndex
+    )
 
-    for (;;) {
-      const {length} = iterators
-      if (!length) break
-      const iterator = iterators[length - 1]
-      scopes.push(iterator.node.type)
-      iterator.node = iterator.node.parent
-      if (iterator.node) {
-        let i = length - 1
-        while (i > 0 && compareScopeDescriptorIterators(iterator, iterators[i - 1]) < 0) i--
-        if (i < length - 1) iterators.splice(i, 0, iterators.pop())
-      } else {
-        iterators.pop()
-      }
-    }
-
-    scopes.push(this.grammar.scopeName)
-    return new ScopeDescriptor({scopes: scopes.reverse()})
+    const nodeTypes = nodes.map(node => node.type)
+    nodeTypes.unshift(this.grammar.scopeName)
+    return new ScopeDescriptor({scopes: nodeTypes})
   }
 
   scopeDescriptorForPosition (point) {
@@ -1141,13 +1126,6 @@ function nodeIsSmaller (left, right) {
   return left.endIndex - left.startIndex < right.endIndex - right.startIndex
 }
 
-function compareScopeDescriptorIterators (a, b) {
-  return (
-    a.node.startIndex - b.node.startIndex ||
-    a.rootStartIndex - b.rootStartIndex
-  )
-}
-
 function last (array) {
   return array[array.length - 1]
 }