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
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
|
//go:generate maleeni compile -l lexspec.json -o clexspec.json
package spec
import (
_ "embed"
"encoding/json"
"fmt"
"io"
"strconv"
"strings"
mldriver "github.com/nihei9/maleeni/driver"
mlspec "github.com/nihei9/maleeni/spec"
verr "github.com/nihei9/vartan/error"
)
type tokenKind string
const (
tokenKindKWFragment = tokenKind("fragment")
tokenKindID = tokenKind("id")
tokenKindTerminalPattern = tokenKind("terminal pattern")
tokenKindStringLiteral = tokenKind("string")
tokenKindColon = tokenKind(":")
tokenKindOr = tokenKind("|")
tokenKindSemicolon = tokenKind(";")
tokenKindDirectiveMarker = tokenKind("#")
tokenKindTreeNodeOpen = tokenKind("#(")
tokenKindTreeNodeClose = tokenKind(")")
tokenKindPosition = tokenKind("$")
tokenKindExpantion = tokenKind("...")
tokenKindMetaDataMarker = tokenKind("%")
tokenKindNewline = tokenKind("newline")
tokenKindEOF = tokenKind("eof")
tokenKindInvalid = tokenKind("invalid")
)
type Position struct {
Row int
Col int
}
func newPosition(row, col int) Position {
return Position{
Row: row,
Col: col,
}
}
type token struct {
kind tokenKind
text string
num int
pos Position
}
func newSymbolToken(kind tokenKind, pos Position) *token {
return &token{
kind: kind,
pos: pos,
}
}
func newIDToken(text string, pos Position) *token {
return &token{
kind: tokenKindID,
text: text,
pos: pos,
}
}
func newTerminalPatternToken(text string, pos Position) *token {
return &token{
kind: tokenKindTerminalPattern,
text: text,
pos: pos,
}
}
func newStringLiteralToken(text string, pos Position) *token {
return &token{
kind: tokenKindStringLiteral,
text: text,
pos: pos,
}
}
func newPositionToken(num int, pos Position) *token {
return &token{
kind: tokenKindPosition,
num: num,
pos: pos,
}
}
func newEOFToken() *token {
return &token{
kind: tokenKindEOF,
}
}
func newInvalidToken(text string, pos Position) *token {
return &token{
kind: tokenKindInvalid,
text: text,
pos: pos,
}
}
type lexer struct {
s *mlspec.CompiledLexSpec
d *mldriver.Lexer
buf *token
}
//go:embed clexspec.json
var lexspec []byte
func newLexer(src io.Reader) (*lexer, error) {
s := &mlspec.CompiledLexSpec{}
err := json.Unmarshal(lexspec, s)
if err != nil {
return nil, err
}
d, err := mldriver.NewLexer(s, src)
if err != nil {
return nil, err
}
return &lexer{
s: s,
d: d,
}, nil
}
func (l *lexer) next() (*token, error) {
if l.buf != nil {
tok := l.buf
l.buf = nil
return tok, nil
}
var newline *token
for {
tok, err := l.lexAndSkipWSs()
if err != nil {
return nil, err
}
if tok.kind == tokenKindNewline {
newline = tok
continue
}
if newline != nil {
l.buf = tok
return newline, nil
}
return tok, nil
}
}
func (l *lexer) lexAndSkipWSs() (*token, error) {
var tok *mldriver.Token
for {
var err error
tok, err = l.d.Next()
if err != nil {
return nil, err
}
if tok.Invalid {
return newInvalidToken(tok.Text(), newPosition(tok.Row+1, tok.Col+1)), nil
}
if tok.EOF {
return newEOFToken(), nil
}
switch tok.KindName {
case "white_space":
continue
case "line_comment":
continue
}
break
}
switch tok.KindName {
case "newline":
return newSymbolToken(tokenKindNewline, newPosition(tok.Row+1, tok.Col+1)), nil
case "kw_fragment":
return newSymbolToken(tokenKindKWFragment, newPosition(tok.Row+1, tok.Col+1)), nil
case "identifier":
if strings.HasPrefix(tok.Text(), "_") {
return nil, &verr.SpecError{
Cause: synErrAutoGenID,
Detail: tok.Text(),
Row: tok.Row + 1,
Col: tok.Col + 1,
}
}
return newIDToken(tok.Text(), newPosition(tok.Row+1, tok.Col+1)), nil
case "terminal_open":
var b strings.Builder
for {
tok, err := l.d.Next()
if err != nil {
return nil, err
}
if tok.EOF {
return nil, &verr.SpecError{
Cause: synErrUnclosedTerminal,
Row: tok.Row + 1,
Col: tok.Col + 1,
}
}
switch tok.KindName {
case "pattern":
// The escape sequences in a pattern string are interpreted by the lexer, except for the \".
// We must interpret the \" before passing them to the lexer because they are delimiters for
// the pattern strings.
fmt.Fprintf(&b, strings.ReplaceAll(tok.Text(), `\"`, `"`))
case "escape_symbol":
return nil, &verr.SpecError{
Cause: synErrIncompletedEscSeq,
Row: tok.Row + 1,
Col: tok.Col + 1,
}
case "terminal_close":
pat := b.String()
if pat == "" {
return nil, &verr.SpecError{
Cause: synErrEmptyPattern,
Row: tok.Row + 1,
Col: tok.Col + 1,
}
}
return newTerminalPatternToken(pat, newPosition(tok.Row+1, tok.Col+1)), nil
}
}
case "string_literal_open":
var b strings.Builder
for {
tok, err := l.d.Next()
if err != nil {
return nil, err
}
if tok.EOF {
return nil, &verr.SpecError{
Cause: synErrUnclosedString,
Row: tok.Row + 1,
Col: tok.Col + 1,
}
}
switch tok.KindName {
case "char_seq":
fmt.Fprintf(&b, tok.Text())
case "escaped_quot":
// Remove '\' character.
fmt.Fprintf(&b, `'`)
case "escaped_back_slash":
// Remove '\' character.
fmt.Fprintf(&b, `\`)
case "escape_symbol":
return nil, &verr.SpecError{
Cause: synErrIncompletedEscSeq,
Row: tok.Row + 1,
Col: tok.Col + 1,
}
case "string_literal_close":
str := b.String()
if str == "" {
return nil, &verr.SpecError{
Cause: synErrEmptyString,
Row: tok.Row + 1,
Col: tok.Col + 1,
}
}
return newStringLiteralToken(str, newPosition(tok.Row+1, tok.Col+1)), nil
}
}
case "colon":
return newSymbolToken(tokenKindColon, newPosition(tok.Row+1, tok.Col+1)), nil
case "or":
return newSymbolToken(tokenKindOr, newPosition(tok.Row+1, tok.Col+1)), nil
case "semicolon":
return newSymbolToken(tokenKindSemicolon, newPosition(tok.Row+1, tok.Col+1)), nil
case "directive_marker":
return newSymbolToken(tokenKindDirectiveMarker, newPosition(tok.Row+1, tok.Col+1)), nil
case "tree_node_open":
return newSymbolToken(tokenKindTreeNodeOpen, newPosition(tok.Row+1, tok.Col+1)), nil
case "tree_node_close":
return newSymbolToken(tokenKindTreeNodeClose, newPosition(tok.Row+1, tok.Col+1)), nil
case "position":
// Remove '$' character and convert to an integer.
num, err := strconv.Atoi(tok.Text()[1:])
if err != nil {
return nil, err
}
if num == 0 {
return nil, &verr.SpecError{
Cause: synErrZeroPos,
Row: tok.Row + 1,
Col: tok.Col + 1,
}
}
return newPositionToken(num, newPosition(tok.Row+1, tok.Col+1)), nil
case "expansion":
return newSymbolToken(tokenKindExpantion, newPosition(tok.Row+1, tok.Col+1)), nil
case "metadata_marker":
return newSymbolToken(tokenKindMetaDataMarker, newPosition(tok.Row+1, tok.Col+1)), nil
default:
return newInvalidToken(tok.Text(), newPosition(tok.Row+1, tok.Col+1)), nil
}
}
|
