Normalize :: syntax (#5048)

* normalize :: syntax

* fixes from code review

lib/coffeescript/grammar.js

@@ -603,6 +603,11 @@
       function() {
         return new Access(new PropertyName('prototype'));
       }),
+      o('?::',
+      function() {
+        return new Access(new PropertyName('prototype'),
+      'soak');
+      }),
       o('Index')
     ],
     // Indexing into an object or array using bracket notation.

lib/coffeescript/lexer.js

@@ -1634,7 +1634,7 @@
   // Other regexes.
   HERECOMMENT_ILLEGAL = /\*\//;
 
-  LINE_CONTINUER = /^\s*(?:,|\??\.(?![.\d])|::)/;
+  LINE_CONTINUER = /^\s*(?:,|\??\.(?![.\d])|\??::)/;
 
   STRING_INVALID_ESCAPE = /((?:^|[^\\])(?:\\\\)*)\\(?:(0[0-7]|[1-7])|(x(?![\da-fA-F]{2}).{0,2})|(u\{(?![\da-fA-F]{1,}\})[^}]*\}?)|(u(?!\{|[\da-fA-F]{4}).{0,4}))/; // Make sure the escape isn’t escaped.
   // octal escape

src/grammar.coffee

@@ -371,6 +371,7 @@ grammar =
     o ':: Property',                            -> [LOC(1)(new Access new PropertyName('prototype')), LOC(2)(new Access $2)]
     o '?:: Property',                           -> [LOC(1)(new Access new PropertyName('prototype'), 'soak'), LOC(2)(new Access $2)]
     o '::',                                     -> new Access new PropertyName 'prototype'
+    o '?::',                                    -> new Access new PropertyName('prototype'), 'soak'
     o 'Index'
   ]
 

src/lexer.coffee

@@ -1293,7 +1293,7 @@ POSSIBLY_DIVISION   = /// ^ /=?\s ///
 # Other regexes.
 HERECOMMENT_ILLEGAL = /\*\//
 
-LINE_CONTINUER      = /// ^ \s* (?: , | \??\.(?![.\d]) | :: ) ///
+LINE_CONTINUER      = /// ^ \s* (?: , | \??\.(?![.\d]) | \??:: ) ///
 
 STRING_INVALID_ESCAPE = ///
   ( (?:^|[^\\]) (?:\\\\)* )        # Make sure the escape isn’t escaped.

test/formatting.coffee

@@ -70,6 +70,12 @@ test "`?.` and `::` should continue lines", ->
     ::
     ?.foo
   )
+
+  ok not (
+    Date
+    ?::
+    ?.foo
+  )
   #eq Object::toString, Date?.
   #prototype
   #::

test/operators.coffee

@@ -303,7 +303,16 @@ test "#2567: Optimization of negated existential produces correct result", ->
 
 test "#2508: Existential access of the prototype", ->
   eq NonExistent?::nothing, undefined
+  eq(
+    NonExistent
+    ?::nothing
+    undefined
+  )
   ok Object?::toString
+  ok(
+    Object
+    ?::toString
+  )
 
 test "floor division operator", ->
   eq 2, 7 // 3