Add new ScopeDescriptor object

src/config.coffee

@@ -9,6 +9,7 @@ pathWatcher = require 'pathwatcher'
 {deprecate} = require 'grim'
 
 ScopedPropertyStore = require 'scoped-property-store'
+ScopeDescriptor = require './scope-descriptor'
 
 # Essential: Used to access all of Atom's configuration details.
 #
@@ -335,7 +336,7 @@ class Config
   #   # do stuff with value
   # ```
   #
-  # * `scopeDescriptor` (optional) {Array} of {String}s describing a path from
+  # * `scopeDescriptor` (optional) {ScopeDescriptor} describing a path from
   #   the root of the syntax tree to a token. Get one by calling
   #   {editor.getLastCursor().getScopeDescriptor()}. See {::get} for examples.
   #   See [the scopes docs](https://atom.io/docs/latest/advanced/scopes-and-scope-descriptors)
@@ -373,7 +374,7 @@ class Config
   # Essential: Add a listener for changes to a given key path. If `keyPath` is
   # not specified, your callback will be called on changes to any key.
   #
-  # * `scopeDescriptor` (optional) {Array} of {String}s describing a path from
+  # * `scopeDescriptor` (optional) {ScopeDescriptor} describing a path from
   #   the root of the syntax tree to a token. Get one by calling
   #   {editor.getLastCursor().getScopeDescriptor()}. See {::get} for examples.
   #   See [the scopes docs](https://atom.io/docs/latest/advanced/scopes-and-scope-descriptors)
@@ -444,7 +445,7 @@ class Config
   # atom.config.get(scopeDescriptor, 'editor.tabLength') # => 2
   # ```
   #
-  # * `scopeDescriptor` (optional) {Array} of {String}s describing a path from
+  # * `scopeDescriptor` (optional) {ScopeDescriptor} describing a path from
   #   the root of the syntax tree to a token. Get one by calling
   #   {editor.getLastCursor().getScopeDescriptor()}
   #   See [the scopes docs](https://atom.io/docs/latest/advanced/scopes-and-scope-descriptors)
@@ -877,8 +878,8 @@ class Config
     @emitter.emit 'did-change'
 
   getRawScopedValue: (scopeDescriptor, keyPath) ->
-    scopeChain = @scopeChainForScopeDescriptor(scopeDescriptor)
-    @scopedSettingsStore.getPropertyValue(scopeChain, keyPath)
+    scopeDescriptor = ScopeDescriptor.create(scopeDescriptor)
+    @scopedSettingsStore.getPropertyValue(scopeDescriptor.getScopeChain(), keyPath)
 
   observeScopedKeyPath: (scopeDescriptor, keyPath, callback) ->
     oldValue = @get(scopeDescriptor, keyPath)
@@ -905,19 +906,8 @@ class Config
   # * language mode uses it for one thing.
   # * autocomplete uses it for editor.completions
   settingsForScopeDescriptor: (scopeDescriptor, keyPath) ->
-    scopeChain = scopeDescriptor
-      .map (scope) ->
-        scope = ".#{scope}" unless scope[0] is '.'
-        scope
-      .join(' ')
-    @scopedSettingsStore.getProperties(scopeChain, keyPath)
-
-  scopeChainForScopeDescriptor: (scopeDescriptor) ->
-    scopeDescriptor
-      .map (scope) ->
-        scope = ".#{scope}" unless scope[0] is '.'
-        scope
-      .join(' ')
+    scopeDescriptor = ScopeDescriptor.create(scopeDescriptor)
+    @scopedSettingsStore.getProperties(scopeDescriptor.getScopeChain(), keyPath)
 
 # Base schema enforcers. These will coerce raw input into the specified type,
 # and will throw an error when the value cannot be coerced. Throwing the error

src/scope-descriptor.coffee

@@ -0,0 +1,23 @@
+
+# Extended:
+module.exports =
+class ScopeDescriptor
+  @create: (descriptor) ->
+    if descriptor instanceof ScopeDescriptor
+      descriptor
+    else
+      new ScopeDescriptor({descriptor})
+
+  ###
+  Section: Construction and Destruction
+  ###
+
+  # Public:
+  constructor: ({@descriptor}) ->
+
+  getScopeChain: ->
+    @descriptor
+      .map (scope) ->
+        scope = ".#{scope}" unless scope[0] is '.'
+        scope
+      .join(' ')