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
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
|
/*
Package parser implements a parser for JavaScript.
import (
"github.com/robertkrimen/otto/parser"
)
Parse and return an AST
filename := "" // A filename is optional
src := `
// Sample xyzzy example
(function(){
if (3.14159 > 0) {
console.log("Hello, World.");
return;
}
var xyzzy = NaN;
console.log("Nothing happens.");
return xyzzy;
})();
`
// Parse some JavaScript, yielding a *ast.Program and/or an ErrorList
program, err := parser.ParseFile(nil, filename, src, 0)
Warning
The parser and AST interfaces are still works-in-progress (particularly where
node types are concerned) and may change in the future.
*/
package parser
import (
"bytes"
"errors"
"io"
"io/ioutil"
"github.com/robertkrimen/otto/ast"
"github.com/robertkrimen/otto/file"
"github.com/robertkrimen/otto/token"
)
// A Mode value is a set of flags (or 0). They control optional parser functionality.
type Mode uint
const (
IgnoreRegExpErrors Mode = 1 << iota // Ignore RegExp compatibility errors (allow backtracking)
)
type _parser struct {
str string
length int
base int
chr rune // The current character
chrOffset int // The offset of current character
offset int // The offset after current character (may be greater than 1)
idx file.Idx // The index of token
token token.Token // The token
literal string // The literal of the token, if any
scope *_scope
insertSemicolon bool // If we see a newline, then insert an implicit semicolon
implicitSemicolon bool // An implicit semicolon exists
errors ErrorList
recover struct {
// Scratch when trying to seek to the next statement, etc.
idx file.Idx
count int
}
mode Mode
file *file.File
}
func _newParser(filename, src string, base int) *_parser {
return &_parser{
chr: ' ', // This is set so we can start scanning by skipping whitespace
str: src,
length: len(src),
base: base,
file: file.NewFile(filename, src, base),
}
}
func newParser(filename, src string) *_parser {
return _newParser(filename, src, 1)
}
func ReadSource(filename string, src interface{}) ([]byte, error) {
if src != nil {
switch src := src.(type) {
case string:
return []byte(src), nil
case []byte:
return src, nil
case *bytes.Buffer:
if src != nil {
return src.Bytes(), nil
}
case io.Reader:
var bfr bytes.Buffer
if _, err := io.Copy(&bfr, src); err != nil {
return nil, err
}
return bfr.Bytes(), nil
}
return nil, errors.New("invalid source")
}
return ioutil.ReadFile(filename)
}
// ParseFile parses the source code of a single JavaScript/ECMAScript source file and returns
// the corresponding ast.Program node.
//
// If fileSet == nil, ParseFile parses source without a FileSet.
// If fileSet != nil, ParseFile first adds filename and src to fileSet.
//
// The filename argument is optional and is used for labelling errors, etc.
//
// src may be a string, a byte slice, a bytes.Buffer, or an io.Reader, but it MUST always be in UTF-8.
//
// // Parse some JavaScript, yielding a *ast.Program and/or an ErrorList
// program, err := parser.ParseFile(nil, "", `if (abc > 1) {}`, 0)
//
func ParseFile(fileSet *file.FileSet, filename string, src interface{}, mode Mode) (*ast.Program, error) {
str, err := ReadSource(filename, src)
if err != nil {
return nil, err
}
{
str := string(str)
base := 1
if fileSet != nil {
base = fileSet.AddFile(filename, str)
}
parser := _newParser(filename, str, base)
parser.mode = mode
return parser.parse()
}
}
// ParseFunction parses a given parameter list and body as a function and returns the
// corresponding ast.FunctionLiteral node.
//
// The parameter list, if any, should be a comma-separated list of identifiers.
//
func ParseFunction(parameterList, body string) (*ast.FunctionLiteral, error) {
src := "(function(" + parameterList + ") {\n" + body + "\n})"
parser := _newParser("", src, 1)
program, err := parser.parse()
if err != nil {
return nil, err
}
return program.Body[0].(*ast.ExpressionStatement).Expression.(*ast.FunctionLiteral), nil
}
func (self *_parser) slice(idx0, idx1 file.Idx) string {
from := int(idx0) - self.base
to := int(idx1) - self.base
if from >= 0 && to <= len(self.str) {
return self.str[from:to]
}
return ""
}
func (self *_parser) parse() (*ast.Program, error) {
self.next()
program := self.parseProgram()
if false {
self.errors.Sort()
}
return program, self.errors.Err()
}
func (self *_parser) next() {
self.token, self.literal, self.idx = self.scan()
}
func (self *_parser) optionalSemicolon() {
if self.token == token.SEMICOLON {
self.next()
return
}
if self.implicitSemicolon {
self.implicitSemicolon = false
return
}
if self.token != token.EOF && self.token != token.RIGHT_BRACE {
self.expect(token.SEMICOLON)
}
}
func (self *_parser) semicolon() {
if self.token != token.RIGHT_PARENTHESIS && self.token != token.RIGHT_BRACE {
if self.implicitSemicolon {
self.implicitSemicolon = false
return
}
self.expect(token.SEMICOLON)
}
}
func (self *_parser) idxOf(offset int) file.Idx {
return file.Idx(self.base + offset)
}
func (self *_parser) expect(value token.Token) file.Idx {
idx := self.idx
if self.token != value {
self.errorUnexpectedToken(self.token)
}
self.next()
return idx
}
func lineCount(str string) (int, int) {
line, last := 0, -1
pair := false
for index, chr := range str {
switch chr {
case '\r':
line += 1
last = index
pair = true
continue
case '\n':
if !pair {
line += 1
}
last = index
case '\u2028', '\u2029':
line += 1
last = index + 2
}
pair = false
}
return line, last
}
func (self *_parser) position(idx file.Idx) file.Position {
position := file.Position{}
offset := int(idx) - self.base
str := self.str[:offset]
position.Filename = self.file.Name()
line, last := lineCount(str)
position.Line = 1 + line
if last >= 0 {
position.Column = offset - last
} else {
position.Column = 1 + len(str)
}
return position
}
|