-
Notifications
You must be signed in to change notification settings - Fork 0
/
parse.go
208 lines (189 loc) · 4.03 KB
/
parse.go
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
package tcl
import (
"bytes"
. "fmt"
"strings"
)
var _ = strings.Index
func White(ch uint8) bool {
return ch == ' ' || ch == '\t' || ch == '\r' || ch == '\n'
}
func WhiteOrSemi(ch uint8) bool {
return ch == ' ' || ch == '\t' || ch == '\r' || ch == '\n' || ch == ';'
}
func (fr *Frame) EvalSeqWithErrorLocation(seq *PSeq) (result T) {
EvalSeqWithErrorLocationCounter.Incr()
defer func() {
if r := recover(); r != nil {
if re, ok := r.(error); ok {
r = re.Error() // Convert error to string.
}
if rs, ok := r.(string); ok {
// TODO: Require debug level for the Eval arg.
src := seq.Src
if len(src) > 100 {
src = src[:100] + "..."
}
r = rs + Sprintf("\n\tin Eval\n\t\t%q", src)
}
panic(r)
}
}()
return seq.Eval(fr)
}
func (fr *Frame) Eval(a T) (result T) {
return a.EvalSeq(fr)
}
func (fr *Frame) EvalString(a string) (result T) {
return MkString(a).EvalSeq(fr)
}
func consumeBackslashEscaped(s string, i int) (byte, int) {
switch s[i+1] {
case 'a':
return '\a', i + 2
case 'b':
return '\b', i + 2
case 'f':
return '\f', i + 2
case 'n':
return '\n', i + 2
case 'r':
return '\r', i + 2
case 't':
return '\t', i + 2
case 'v':
return '\v', i + 2
case 'x':
panic("Hexadecimal Backslash Escapes not supported (yet)")
}
if s[i+1] < '0' || s[i+1] > '7' {
return s[i+1], i + 2 // Default for all other cases is the escaped char.
}
if s[i+2] < '0' || s[i+2] > '7' {
panic(Sprintf("Second character after backslash is not octal %q.", s[i:i+3]))
}
if s[i+3] < '0' || s[i+3] > '7' {
panic(Sprintf("Third character after backslash is not octal %q.", s[i:i+4]))
}
a := s[i+1] - '0'
b := s[i+2] - '0'
c := s[i+3] - '0'
return byte(a*64 + b*8 + c), i + 4
}
type SubstFlags int
const (
NoDollar SubstFlags = 1 << iota
NoSquare
NoBackslash
)
func (fr *Frame) SubstString(s string, flags SubstFlags) string {
SubstStringCounter.Incr()
lex := NewLex(s)
lex.Pos = 0 // Rewind after the builtin Advance()
lex.Next = 0 // Rewind after the builtin Advance()
buf := bytes.NewBuffer(nil)
for lex.Next < lex.Len {
var c byte = lex.Str[lex.Next]
if c == '[' && (flags&NoSquare) == 0 {
lex.Pos = lex.Next // Refocus on the open square.
lex.Next = lex.Pos + 1
lex.Tok = '['
part := Parse2Square(lex)
MustTok(Token(']'), lex.Tok)
str := part.Eval(fr).String()
buf.WriteString(str)
} else if c == '$' && (flags&NoDollar) == 0 {
lex.Pos = lex.Next // Refocus on the dollar.
lex.Next = lex.Pos + 1
lex.Tok = '$'
part := Parse2Dollar(lex)
str := part.Eval(fr).String()
buf.WriteString(str)
} else if c == '\\' && (flags&NoBackslash) == 0 {
c = lex.StretchBackslashEscaped()
buf.WriteByte(c)
} else {
lex.Stretch1()
buf.WriteByte(c)
}
}
return buf.String()
}
func ParseListOrRecover(s string) (recs []T, err interface{}) {
defer func() {
err = recover()
}()
recs = ParseList(s)
return
}
func ParseList(s string) []T {
ParseListCounter.Incr()
n := len(s)
i := 0
z := make([]T, 0, 4)
for i < n {
var c uint8
// skip space
for i < n {
c = s[i]
if !White(s[i]) {
break
}
i++
}
if i == n {
break
}
buf := bytes.NewBuffer(nil)
// found non-white
if c == '{' {
i++
c = s[i]
b := 1
for i < n {
c = s[i]
switch c {
case '{':
b++
case '}':
b--
case '\\':
c, i = consumeBackslashEscaped(s, i)
i -= 1
}
if b == 0 {
break
}
buf.WriteByte(c)
i++
}
if c != '}' {
panic("ParseList: missing end brace:" + Repr(c))
}
i++
} else {
for i < n {
c = s[i]
if White(s[i]) {
break
}
if c == '\\' {
c, i = consumeBackslashEscaped(s, i)
i -= 1
}
buf.WriteByte(c)
i++
}
}
z = append(z, MkString(buf.String()))
}
return z
}
var SubstStringCounter Counter
var ParseListCounter Counter
var EvalSeqWithErrorLocationCounter Counter
func init() {
SubstStringCounter.Register("SubstString")
ParseListCounter.Register("ParseList")
EvalSeqWithErrorLocationCounter.Register("EvalSeqWithErrorLocation")
}