Kronuz · LivingInSyn · May 24, 2021 · May 24, 2021 · May 24, 2021 · May 24, 2021
diff --git a/esprima/messages.py b/esprima/messages.py
@@ -54,6 +54,7 @@ class Messages:
     InvalidLHSInForLoop = "Invalid left-hand side in for-loop"
     InvalidModuleSpecifier = "Unexpected token"
     InvalidRegExp = "Invalid regular expression"
+    InvalidTaggedTemplateOnOptionalChain = 'Invalid tagged template on optional chain'
     LetInLexicalBinding = "let is disallowed as a lexically bound name"
     MissingFromClause = "Unexpected token"
     MultipleDefaultsInSwitch = "More than one default clause in switch statement"

diff --git a/esprima/nodes.py b/esprima/nodes.py
@@ -138,10 +138,11 @@ def __init__(self, label):
 
 
 class CallExpression(Node):
-    def __init__(self, callee, args):
+    def __init__(self, callee, args, optional):
         self.type = Syntax.CallExpression
         self.callee = callee
         self.arguments = args
+        self.optional = optional
 
 
 class CatchClause(Node):
@@ -150,6 +151,11 @@ def __init__(self, param, body):
         self.param = param
         self.body = body
 
+class ChainExpression(Node):
+    def __init__(self, expression):
+        self.type = Syntax.ChainExpression
+        self.expression = expression
+
 
 class ClassBody(Node):
     def __init__(self, body):
@@ -174,11 +180,12 @@ def __init__(self, id, superClass, body):
 
 
 class ComputedMemberExpression(Node):
-    def __init__(self, object, property):
+    def __init__(self, object, property, optional):
         self.type = Syntax.MemberExpression
         self.computed = True
         self.object = object
         self.property = property
+        self.optional = optional
 
 
 class ConditionalExpression(Node):
@@ -472,11 +479,12 @@ def __init__(self, argument):
 
 
 class StaticMemberExpression(Node):
-    def __init__(self, object, property):
+    def __init__(self, object, property, optional):
         self.type = Syntax.MemberExpression
         self.computed = False
         self.object = object
         self.property = property
+        self.optional = optional
 
 
 class Super(Node):

diff --git a/esprima/parser.py b/esprima/parser.py
@@ -1095,15 +1095,15 @@ def parseLeftHandSideExpressionAllowCall(self):
         else:
             expr = self.inheritCoverGrammar(self.parseNewExpression if self.matchKeyword('new') else self.parsePrimaryExpression)
 
+        hasOptional = False
         while True:
-            if self.match('.'):
-                self.context.isBindingElement = False
-                self.context.isAssignmentTarget = True
-                self.expect('.')
-                property = self.parseIdentifierName()
-                expr = self.finalize(self.startNode(startToken), Node.StaticMemberExpression(expr, property))
+            optional = False
+            if self.match('?.'):
+                optional = True
+                hasOptional = True
+                self.expect('?.')
 
-            elif self.match('('):
+            if self.match('('):
                 asyncArrow = maybeAsync and (startToken.lineNumber == self.lookahead.lineNumber)
                 self.context.isBindingElement = False
                 self.context.isAssignmentTarget = False
@@ -1113,27 +1113,43 @@ def parseLeftHandSideExpressionAllowCall(self):
                     args = self.parseArguments()
                 if expr.type is Syntax.Import and len(args) != 1:
                     self.tolerateError(Messages.BadImportCallArity)
-                expr = self.finalize(self.startNode(startToken), Node.CallExpression(expr, args))
+                expr = self.finalize(self.startNode(startToken), Node.CallExpression(expr, args, optional))
                 if asyncArrow and self.match('=>'):
                     for arg in args:
                         self.reinterpretExpressionAsPattern(arg)
                     expr = Node.AsyncArrowParameterPlaceHolder(args)
             elif self.match('['):
                 self.context.isBindingElement = False
-                self.context.isAssignmentTarget = True
+                self.context.isAssignmentTarget = not optional
                 self.expect('[')
                 property = self.isolateCoverGrammar(self.parseExpression)
                 self.expect(']')
-                expr = self.finalize(self.startNode(startToken), Node.ComputedMemberExpression(expr, property))
+                expr = self.finalize(self.startNode(startToken), Node.ComputedMemberExpression(expr, property, optional))
 
             elif self.lookahead.type is Token.Template and self.lookahead.head:
+                # Optional template literal is not included in the spec.
+                # https://github.com/tc39/proposal-optional-chaining/issues/54
+                if optional:
+                    self.throwUnexpectedToken(self.lookahead)
+                if hasOptional:
+                    self.throwError(Messages.InvalidTaggedTemplateOnOptionalChain)
                 quasi = self.parseTemplateLiteral()
                 expr = self.finalize(self.startNode(startToken), Node.TaggedTemplateExpression(expr, quasi))
 
+            elif self.match('.') or optional:
+                self.context.isBindingElement = False
+                self.context.isAssignmentTarget = not optional
+                if not optional:
+                    self.expect('.')
+                property = self.parseIdentifierName()
+                expr = self.finalize(self.startNode(startToken), Node.StaticMemberExpression(expr, property, optional))
+
             else:
                 break
 
         self.context.allowIn = previousAllowIn
+        if hasOptional:
+            return Node.ChainExpression(expr)
 
         return expr
 
@@ -1155,29 +1171,46 @@ def parseLeftHandSideExpression(self):
         else:
             expr = self.inheritCoverGrammar(self.parseNewExpression if self.matchKeyword('new') else self.parsePrimaryExpression)
 
+        hasOptional = False
         while True:
+            optional = False
+            if self.match('?.'):
+                optional = True
+                hasOptional = True
+                self.expect('?.')
+
             if self.match('['):
                 self.context.isBindingElement = False
-                self.context.isAssignmentTarget = True
+                self.context.isAssignmentTarget = not optional
                 self.expect('[')
                 property = self.isolateCoverGrammar(self.parseExpression)
                 self.expect(']')
-                expr = self.finalize(node, Node.ComputedMemberExpression(expr, property))
-
-            elif self.match('.'):
-                self.context.isBindingElement = False
-                self.context.isAssignmentTarget = True
-                self.expect('.')
-                property = self.parseIdentifierName()
-                expr = self.finalize(node, Node.StaticMemberExpression(expr, property))
+                expr = self.finalize(node, Node.ComputedMemberExpression(expr, property, optional))
 
             elif self.lookahead.type is Token.Template and self.lookahead.head:
+                # Optional template literal is not included in the spec.
+                # https://github.com/tc39/proposal-optional-chaining/issues/54
+                if optional:
+                    self.throwUnexpectedToken(self.lookahead)
+                if hasOptional:
+                    self.throwError(Messages.InvalidTaggedTemplateOnOptionalChain)
                 quasi = self.parseTemplateLiteral()
                 expr = self.finalize(node, Node.TaggedTemplateExpression(expr, quasi))
 
+            elif self.match('.') or optional:
+                self.context.isBindingElement = False
+                self.context.isAssignmentTarget = not optional
+                if not optional:
+                    self.expect('.')
+                property = self.parseIdentifierName()
+                expr = self.finalize(node, Node.StaticMemberExpression(expr, property, optional))
+
             else:
                 break
 
+        if hasOptional:
+            return Node.ChainExpression(expr)
+
         return expr
 
     # https://tc39.github.io/ecma262/#sec-update-expressions

diff --git a/esprima/scanner.py b/esprima/scanner.py
@@ -563,14 +563,24 @@ def scanPunctuator(self):
             if self.curlyStack:
                 self.curlyStack.pop()
 
+        elif str == '?':
+            self.index += 1
+            if self.source[self.index] == '?':
+                self.index += 1
+                str = '??'
+            if self.source[self.index] == '.' and not self.source[self.index + 1].isdigit():
+                # "?." in "foo?.3:0" should not be treated as optional chaining.
+                # See https://github.com/tc39/proposal-optional-chaining#notes
+                self.index += 1
+                str = '?.'
+
         elif str in (
             ')',
             ';',
             ',',
             '[',
             ']',
             ':',
-            '?',
             '~',
         ):
             self.index += 1

diff --git a/esprima/syntax.py b/esprima/syntax.py
@@ -36,6 +36,7 @@ class Syntax:
     BreakStatement = "BreakStatement"
     CallExpression = "CallExpression"
     CatchClause = "CatchClause"
+    ChainExpression = 'ChainExpression'
     ClassBody = "ClassBody"
     ClassDeclaration = "ClassDeclaration"
     ClassExpression = "ClassExpression"

diff --git a/test/fixtures/ES6/arrow-function/migrated_0018.tree.json b/test/fixtures/ES6/arrow-function/migrated_0018.tree.json
@@ -65,6 +65,7 @@
                         }
                     }
                 ],
+                "optional": false,
                 "range": [
                     0,
                     13

diff --git a/test/fixtures/ES6/arrow-function/migrated_0019.tree.json b/test/fixtures/ES6/arrow-function/migrated_0019.tree.json
@@ -102,6 +102,7 @@
                         }
                     }
                 ],
+                "optional": false,
                 "range": [
                     0,
                     17

diff --git a/test/fixtures/ES6/destructuring-assignment/array-pattern/member-expr-in-rest.tree.json b/test/fixtures/ES6/destructuring-assignment/array-pattern/member-expr-in-rest.tree.json
@@ -120,7 +120,8 @@
                                     "type": "Literal",
                                     "value": 0,
                                     "raw": "0"
-                                }
+                                },
+                                "optional": false
                             }
                         }
                     ]

diff --git a/test/fixtures/ES6/destructuring-assignment/array-pattern/nested-assignment.tree.json b/test/fixtures/ES6/destructuring-assignment/array-pattern/nested-assignment.tree.json
@@ -243,7 +243,8 @@
                                                 "type": "Literal",
                                                 "value": 0,
                                                 "raw": "0"
-                                            }
+                                            },
+                                            "optional": false
                                         }
                                     }
                                 ]

diff --git a/test/fixtures/ES6/destructuring-assignment/object-pattern/nested-cover-grammar.tree.json b/test/fixtures/ES6/destructuring-assignment/object-pattern/nested-cover-grammar.tree.json
@@ -513,7 +513,8 @@
                                                                                                                                                                                                         "type": "Literal",
                                                                                                                                                                                                         "value": 0,
                                                                                                                                                                                                         "raw": "0"
-                                                                                                                                                                                                    }
+                                                                                                                                                                                                    },
+                                                                                                                                                                                                    "optional": false
                                                                                                                                                                                                 }
                                                                                                                                                                                             },
                                                                                                                                                                                             "kind": "init",

diff --git a/.../fixtures/ES6/destructuring-assignment/object-pattern/object-pattern-assignment.tree.json b/.../fixtures/ES6/destructuring-assignment/object-pattern/object-pattern-assignment.tree.json
@@ -458,7 +458,8 @@
                                         "type": "Identifier",
                                         "name": "some_call"
                                     },
-                                    "arguments": []
+                                    "arguments": [],
+                                    "optional": false
                                 },
                                 "property": {
                                     "range": [
@@ -477,7 +478,8 @@
                                     },
                                     "type": "Identifier",
                                     "name": "a"
-                                }
+                                },
+                                "optional": false
                             },
                             "kind": "init",
                             "method": false,
@@ -569,7 +571,8 @@
                                     },
                                     "type": "Identifier",
                                     "name": "a"
-                                }
+                                },
+                                "optional": false
                             },
                             "kind": "init",
                             "method": false,

diff --git a/test/fixtures/ES6/lexical-declaration/let_member.tree.json b/test/fixtures/ES6/lexical-declaration/let_member.tree.json
@@ -100,7 +100,8 @@
                         },
                         "type": "Identifier",
                         "name": "let"
-                    }
+                    },
+                    "optional": false
                 },
                 "right": {
                     "range": [

diff --git a/test/fixtures/ES6/meta-property/new-target-invoke.tree.json b/test/fixtures/ES6/meta-property/new-target-invoke.tree.json
@@ -152,7 +152,8 @@
                                     "name": "target"
                                 }
                             },
-                            "arguments": []
+                            "arguments": [],
+                            "optional": false
                         }
                     }
                 ]

diff --git a/test/fixtures/ES6/meta-property/new-target-precedence.tree.json b/test/fixtures/ES6/meta-property/new-target-precedence.tree.json
@@ -170,7 +170,8 @@
                                 },
                                 "arguments": []
                             },
-                            "arguments": []
+                            "arguments": [],
+                            "optional": false
                         }
                     }
                 ]

diff --git a/test/fixtures/ES6/spread-element/call-multi-spread.tree.json b/test/fixtures/ES6/spread-element/call-multi-spread.tree.json
@@ -157,7 +157,8 @@
                             "name": "z"
                         }
                     }
-                ]
+                ],
+                "optional": false
             }
         }
     ],

diff --git a/test/fixtures/ES6/spread-element/call-spread-default.tree.json b/test/fixtures/ES6/spread-element/call-spread-default.tree.json
@@ -53,6 +53,8 @@
                 },
                 "arguments": [
                     {
+                        "type": "Identifier",
+                        "name": "g",
                         "range": [
                             2,
                             3
@@ -66,9 +68,7 @@
                                 "line": 1,
                                 "column": 3
                             }
-                        },
-                        "type": "Identifier",
-                        "name": "g"
+                        }
                     },
                     {
                         "range": [
@@ -141,7 +141,8 @@
                             }
                         }
                     }
-                ]
+                ],
+                "optional": false
             }
         }
     ],
@@ -342,4 +343,4 @@
             "column": 15
         }
     }
-}
+}
diff --git a/test/fixtures/ES6/spread-element/call-spread-first.tree.json b/test/fixtures/ES6/spread-element/call-spread-first.tree.json
@@ -123,7 +123,8 @@
                         "type": "Identifier",
                         "name": "z"
                     }
-                ]
+                ],
+                "optional": false
             }
         }
     ],

diff --git a/test/fixtures/ES6/spread-element/call-spread-number.tree.json b/test/fixtures/ES6/spread-element/call-spread-number.tree.json
@@ -88,7 +88,8 @@
                             "raw": ".5"
                         }
                     }
-                ]
+                ],
+                "optional": false
             }
         }
     ],
-Original file line number
+Diff line change
@@ Expand Up / @@ -65,6 +65,7 @@ @@
                             }
                         }
                     ],
+                    "optional": false,
                     "range": [
 ,
@@ Expand Down @@