1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
|
import {types as tt} from "./tokentype"
import {Parser} from "./state"
import {has} from "./util"
const pp = Parser.prototype
// Convert existing expression atom to assignable pattern
// if possible.
pp.toAssignable = function(node, isBinding) {
if (this.options.ecmaVersion >= 6 && node) {
switch (node.type) {
case "Identifier":
case "ObjectPattern":
case "ArrayPattern":
break
case "ObjectExpression":
node.type = "ObjectPattern"
for (let i = 0; i < node.properties.length; i++) {
let prop = node.properties[i]
if (prop.kind !== "init") this.raise(prop.key.start, "Object pattern can't contain getter or setter")
this.toAssignable(prop.value, isBinding)
}
break
case "ArrayExpression":
node.type = "ArrayPattern"
this.toAssignableList(node.elements, isBinding)
break
case "AssignmentExpression":
if (node.operator === "=") {
node.type = "AssignmentPattern"
delete node.operator
// falls through to AssignmentPattern
} else {
this.raise(node.left.end, "Only '=' operator can be used for specifying default value.")
break
}
case "AssignmentPattern":
if (node.right.type === "YieldExpression")
this.raise(node.right.start, "Yield expression cannot be a default value")
break
case "ParenthesizedExpression":
node.expression = this.toAssignable(node.expression, isBinding)
break
case "MemberExpression":
if (!isBinding) break
default:
this.raise(node.start, "Assigning to rvalue")
}
}
return node
}
// Convert list of expression atoms to binding list.
pp.toAssignableList = function(exprList, isBinding) {
let end = exprList.length
if (end) {
let last = exprList[end - 1]
if (last && last.type == "RestElement") {
--end
} else if (last && last.type == "SpreadElement") {
last.type = "RestElement"
let arg = last.argument
this.toAssignable(arg, isBinding)
if (arg.type !== "Identifier" && arg.type !== "MemberExpression" && arg.type !== "ArrayPattern")
this.unexpected(arg.start)
--end
}
if (isBinding && last && last.type === "RestElement" && last.argument.type !== "Identifier")
this.unexpected(last.argument.start)
}
for (let i = 0; i < end; i++) {
let elt = exprList[i]
if (elt) this.toAssignable(elt, isBinding)
}
return exprList
}
// Parses spread element.
pp.parseSpread = function(refDestructuringErrors) {
let node = this.startNode()
this.next()
node.argument = this.parseMaybeAssign(false, refDestructuringErrors)
return this.finishNode(node, "SpreadElement")
}
pp.parseRest = function(allowNonIdent) {
let node = this.startNode()
this.next()
// RestElement inside of a function parameter must be an identifier
if (allowNonIdent) node.argument = this.type === tt.name ? this.parseIdent() : this.unexpected()
else node.argument = this.type === tt.name || this.type === tt.bracketL ? this.parseBindingAtom() : this.unexpected()
return this.finishNode(node, "RestElement")
}
// Parses lvalue (assignable) atom.
pp.parseBindingAtom = function() {
if (this.options.ecmaVersion < 6) return this.parseIdent()
switch (this.type) {
case tt.name:
return this.parseIdent()
case tt.bracketL:
let node = this.startNode()
this.next()
node.elements = this.parseBindingList(tt.bracketR, true, true)
return this.finishNode(node, "ArrayPattern")
case tt.braceL:
return this.parseObj(true)
default:
this.unexpected()
}
}
pp.parseBindingList = function(close, allowEmpty, allowTrailingComma, allowNonIdent) {
let elts = [], first = true
while (!this.eat(close)) {
if (first) first = false
else this.expect(tt.comma)
if (allowEmpty && this.type === tt.comma) {
elts.push(null)
} else if (allowTrailingComma && this.afterTrailingComma(close)) {
break
} else if (this.type === tt.ellipsis) {
let rest = this.parseRest(allowNonIdent)
this.parseBindingListItem(rest)
elts.push(rest)
if (this.type === tt.comma) this.raise(this.start, "Comma is not permitted after the rest element")
this.expect(close)
break
} else {
let elem = this.parseMaybeDefault(this.start, this.startLoc)
this.parseBindingListItem(elem)
elts.push(elem)
}
}
return elts
}
pp.parseBindingListItem = function(param) {
return param
}
// Parses assignment pattern around given atom if possible.
pp.parseMaybeDefault = function(startPos, startLoc, left) {
left = left || this.parseBindingAtom()
if (this.options.ecmaVersion < 6 || !this.eat(tt.eq)) return left
let node = this.startNodeAt(startPos, startLoc)
node.left = left
node.right = this.parseMaybeAssign()
return this.finishNode(node, "AssignmentPattern")
}
// Verify that a node is an lval — something that can be assigned
// to.
pp.checkLVal = function(expr, isBinding, checkClashes) {
switch (expr.type) {
case "Identifier":
if (this.strict && this.reservedWordsStrictBind.test(expr.name))
this.raiseRecoverable(expr.start, (isBinding ? "Binding " : "Assigning to ") + expr.name + " in strict mode")
if (checkClashes) {
if (has(checkClashes, expr.name))
this.raiseRecoverable(expr.start, "Argument name clash")
checkClashes[expr.name] = true
}
break
case "MemberExpression":
if (isBinding) this.raiseRecoverable(expr.start, (isBinding ? "Binding" : "Assigning to") + " member expression")
break
case "ObjectPattern":
for (let i = 0; i < expr.properties.length; i++)
this.checkLVal(expr.properties[i].value, isBinding, checkClashes)
break
case "ArrayPattern":
for (let i = 0; i < expr.elements.length; i++) {
let elem = expr.elements[i]
if (elem) this.checkLVal(elem, isBinding, checkClashes)
}
break
case "AssignmentPattern":
this.checkLVal(expr.left, isBinding, checkClashes)
break
case "RestElement":
this.checkLVal(expr.argument, isBinding, checkClashes)
break
case "ParenthesizedExpression":
this.checkLVal(expr.expression, isBinding, checkClashes)
break
default:
this.raise(expr.start, (isBinding ? "Binding" : "Assigning to") + " rvalue")
}
}
|
