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
|
/**************************************************************************/
/* */
/* OCaml */
/* */
/* Xavier Leroy, projet Cristal, INRIA Rocquencourt */
/* */
/* Copyright 1996 Institut National de Recherche en Informatique et */
/* en Automatique. */
/* */
/* All rights reserved. This file is distributed under the terms of */
/* the GNU Lesser General Public License version 2.1, with the */
/* special exception on linking described in the file LICENSE. */
/* */
/**************************************************************************/
#define CAML_INTERNALS
/* The PDA automaton for parsers generated by camlyacc */
#include <stdio.h>
#include <string.h>
#include "caml/config.h"
#include "caml/mlvalues.h"
#include "caml/memory.h"
#include "caml/alloc.h"
#define ERRCODE 256
struct parser_tables { /* Mirrors parse_tables in ../stdlib/parsing.mli */
value actions;
value transl_const;
value transl_block;
char * lhs;
char * len;
char * defred;
char * dgoto;
char * sindex;
char * rindex;
char * gindex;
value tablesize;
char * table;
char * check;
value error_function;
char * names_const;
char * names_block;
};
struct parser_env { /* Mirrors parser_env in ../stdlib/parsing.ml */
value s_stack;
value v_stack;
value symb_start_stack;
value symb_end_stack;
value stacksize;
value stackbase;
value curr_char;
value lval;
value symb_start;
value symb_end;
value asp;
value rule_len;
value rule_number;
value sp;
value state;
value errflag;
};
#if defined(ARCH_BIG_ENDIAN) || SIZEOF_SHORT != 2
#define Short(tbl,n) \
(*((unsigned char *)((tbl) + (n) * 2)) + \
(*((signed char *)((tbl) + (n) * 2 + 1)) << 8))
#else
#define Short(tbl,n) (((short *)(tbl))[n])
#endif
int caml_parser_trace = 0;
/* Input codes */
/* Mirrors parser_input in ../stdlib/parsing.ml */
#define START 0
#define TOKEN_READ 1
#define STACKS_GROWN_1 2
#define STACKS_GROWN_2 3
#define SEMANTIC_ACTION_COMPUTED 4
#define ERROR_DETECTED 5
/* Output codes */
/* Mirrors parser_output in ../stdlib/parsing.ml */
#define READ_TOKEN Val_int(0)
#define RAISE_PARSE_ERROR Val_int(1)
#define GROW_STACKS_1 Val_int(2)
#define GROW_STACKS_2 Val_int(3)
#define COMPUTE_SEMANTIC_ACTION Val_int(4)
#define CALL_ERROR_FUNCTION Val_int(5)
/* To preserve local variables when communicating with the ML code */
#define SAVE \
env->sp = Val_int(sp), \
env->state = Val_int(state), \
env->errflag = Val_int(errflag)
#define RESTORE \
sp = Int_val(env->sp), \
state = Int_val(env->state), \
errflag = Int_val(env->errflag)
/* Auxiliary for printing token just read */
static char * token_name(char * names, int number)
{
for (/*nothing*/; number > 0; number--) {
if (names[0] == 0) return "<unknown token>";
names += strlen(names) + 1;
}
return names;
}
static void print_token(struct parser_tables *tables, int state, value tok)
{
value v;
if (Is_long(tok)) {
fprintf(stderr, "State %d: read token %s\n",
state, token_name(tables->names_const, Int_val(tok)));
} else {
fprintf(stderr, "State %d: read token %s(",
state, token_name(tables->names_block, Tag_val(tok)));
v = Field(tok, 0);
if (Is_long(v))
fprintf(stderr, "%" ARCH_INTNAT_PRINTF_FORMAT "d", Long_val(v));
else if (Tag_val(v) == String_tag)
fprintf(stderr, "%s", String_val(v));
else if (Tag_val(v) == Double_tag)
fprintf(stderr, "%g", Double_val(v));
else
fprintf(stderr, "_");
fprintf(stderr, ")\n");
}
}
/* The pushdown automata */
CAMLprim value caml_parse_engine(struct parser_tables *tables,
struct parser_env *env, value cmd, value arg)
{
int state;
mlsize_t sp, asp;
int errflag;
int n, n1, n2, m, state1;
switch(Int_val(cmd)) {
case START:
state = 0;
sp = Int_val(env->sp);
errflag = 0;
loop:
n = Short(tables->defred, state);
if (n != 0) goto reduce;
if (Int_val(env->curr_char) >= 0) goto testshift;
SAVE;
return READ_TOKEN;
/* The ML code calls the lexer and updates */
/* symb_start and symb_end */
case TOKEN_READ:
RESTORE;
if (Is_block(arg)) {
env->curr_char = Field(tables->transl_block, Tag_val(arg));
caml_modify(&env->lval, Field(arg, 0));
} else {
env->curr_char = Field(tables->transl_const, Int_val(arg));
caml_modify(&env->lval, Val_long(0));
}
if (caml_parser_trace) print_token(tables, state, arg);
testshift:
n1 = Short(tables->sindex, state);
n2 = n1 + Int_val(env->curr_char);
if (n1 != 0 && n2 >= 0 && n2 <= Int_val(tables->tablesize) &&
Short(tables->check, n2) == Int_val(env->curr_char)) goto shift;
n1 = Short(tables->rindex, state);
n2 = n1 + Int_val(env->curr_char);
if (n1 != 0 && n2 >= 0 && n2 <= Int_val(tables->tablesize) &&
Short(tables->check, n2) == Int_val(env->curr_char)) {
n = Short(tables->table, n2);
goto reduce;
}
if (errflag > 0) goto recover;
SAVE;
return CALL_ERROR_FUNCTION;
/* The ML code calls the error function */
case ERROR_DETECTED:
RESTORE;
recover:
if (errflag < 3) {
errflag = 3;
while (1) {
state1 = Int_val(Field(env->s_stack, sp));
n1 = Short(tables->sindex, state1);
n2 = n1 + ERRCODE;
if (n1 != 0 && n2 >= 0 && n2 <= Int_val(tables->tablesize) &&
Short(tables->check, n2) == ERRCODE) {
if (caml_parser_trace)
fprintf(stderr, "Recovering in state %d\n", state1);
goto shift_recover;
} else {
if (caml_parser_trace){
fprintf(stderr, "Discarding state %d\n", state1);
}
if (sp <= Int_val(env->stackbase)) {
if (caml_parser_trace){
fprintf(stderr, "No more states to discard\n");
}
return RAISE_PARSE_ERROR; /* The ML code raises Parse_error */
}
sp--;
}
}
} else {
if (Int_val(env->curr_char) == 0)
return RAISE_PARSE_ERROR; /* The ML code raises Parse_error */
if (caml_parser_trace) fprintf(stderr, "Discarding last token read\n");
env->curr_char = Val_int(-1);
goto loop;
}
shift:
env->curr_char = Val_int(-1);
if (errflag > 0) errflag--;
shift_recover:
if (caml_parser_trace)
fprintf(stderr, "State %d: shift to state %d\n",
state, Short(tables->table, n2));
state = Short(tables->table, n2);
sp++;
if (sp < Long_val(env->stacksize)) goto push;
SAVE;
return GROW_STACKS_1;
/* The ML code resizes the stacks */
case STACKS_GROWN_1:
RESTORE;
push:
Field(env->s_stack, sp) = Val_int(state);
caml_modify(&Field(env->v_stack, sp), env->lval);
Store_field (env->symb_start_stack, sp, env->symb_start);
Store_field (env->symb_end_stack, sp, env->symb_end);
goto loop;
reduce:
if (caml_parser_trace)
fprintf(stderr, "State %d: reduce by rule %d\n", state, n);
m = Short(tables->len, n);
env->asp = Val_int(sp);
env->rule_number = Val_int(n);
env->rule_len = Val_int(m);
sp = sp - m + 1;
m = Short(tables->lhs, n);
state1 = Int_val(Field(env->s_stack, sp - 1));
n1 = Short(tables->gindex, m);
n2 = n1 + state1;
if (n1 != 0 && n2 >= 0 && n2 <= Int_val(tables->tablesize) &&
Short(tables->check, n2) == state1) {
state = Short(tables->table, n2);
} else {
state = Short(tables->dgoto, m);
}
if (sp < Long_val(env->stacksize)) goto semantic_action;
SAVE;
return GROW_STACKS_2;
/* The ML code resizes the stacks */
case STACKS_GROWN_2:
RESTORE;
semantic_action:
SAVE;
return COMPUTE_SEMANTIC_ACTION;
/* The ML code calls the semantic action */
case SEMANTIC_ACTION_COMPUTED:
RESTORE;
Field(env->s_stack, sp) = Val_int(state);
caml_modify(&Field(env->v_stack, sp), arg);
asp = Int_val(env->asp);
Store_field (env->symb_end_stack, sp, Field(env->symb_end_stack, asp));
if (sp > asp) {
/* This is an epsilon production. Take symb_start equal to symb_end. */
Store_field (env->symb_start_stack, sp, Field(env->symb_end_stack, asp));
}
goto loop;
default: /* Should not happen */
CAMLassert(0);
return RAISE_PARSE_ERROR; /* Keeps gcc -Wall happy */
}
}
/* Control printing of debugging info */
CAMLprim value caml_set_parser_trace(value flag)
{
value oldflag = Val_bool(caml_parser_trace);
caml_parser_trace = Bool_val(flag);
return oldflag;
}
|
