blob: af83e15d48aeaf730b2935a923b2d3c4a7ccf647 (
plain)
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
|
(***********************************************************************)
(* *)
(* Caml Special Light *)
(* *)
(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
(* *)
(* Copyright 1995 Institut National de Recherche en Informatique et *)
(* Automatique. Distributed only by permission. *)
(* *)
(***********************************************************************)
(* $Id$ *)
(* The parsing engine *)
open Lexing
(* Internal interface to the parsing engine *)
type parser_env =
{ mutable s_stack : int array; (* States *)
mutable v_stack : Obj.t array; (* Semantic attributes *)
mutable symb_start_stack : int array; (* Start positions *)
mutable symb_end_stack : int array; (* End positions *)
mutable stacksize : int; (* Size of the stacks *)
mutable stackbase : int; (* Base sp for current parse *)
mutable curr_char : int; (* Last token read *)
mutable lval : Obj.t; (* Its semantic attribute *)
mutable symb_start : int; (* Start pos. of the current symbol*)
mutable symb_end : int; (* End pos. of the current symbol *)
mutable asp : int; (* The stack pointer for attributes *)
mutable rule_len : int; (* Number of rhs items in the rule *)
mutable rule_number : int; (* Rule number to reduce by *)
mutable sp : int; (* Saved sp for parse_engine *)
mutable state : int; (* Saved state for parse_engine *)
mutable errflag : int } (* Saved error flag for parse_engine *)
type parse_tables =
{ actions : (parser_env -> Obj.t) array;
transl_const : int array;
transl_block : int array;
lhs : string;
len : string;
defred : string;
dgoto : string;
sindex : string;
rindex : string;
gindex : string;
tablesize : int;
table : string;
check : string;
error_function : string -> unit }
exception YYexit of Obj.t
exception Parse_error
type parser_input =
Start
| Token_read
| Stacks_grown_1
| Stacks_grown_2
| Semantic_action_computed
| Error_detected
type parser_output =
Read_token
| Raise_parse_error
| Grow_stacks_1
| Grow_stacks_2
| Compute_semantic_action
| Call_error_function
external parse_engine :
parse_tables -> parser_env -> parser_input -> Obj.t -> parser_output
= "parse_engine"
let env =
{ s_stack = Array.create 100 0;
v_stack = Array.create 100 (Obj.repr ());
symb_start_stack = Array.create 100 0;
symb_end_stack = Array.create 100 0;
stacksize = 100;
stackbase = 0;
curr_char = 0;
lval = Obj.repr ();
symb_start = 0;
symb_end = 0;
asp = 0;
rule_len = 0;
rule_number = 0;
sp = 0;
state = 0;
errflag = 0 }
let grow_stacks() =
let oldsize = env.stacksize in
let newsize = oldsize * 2 in
let new_s = Array.create newsize 0
and new_v = Array.create newsize (Obj.repr ())
and new_start = Array.create newsize 0
and new_end = Array.create newsize 0 in
Array.blit env.s_stack 0 new_s 0 oldsize;
env.s_stack <- new_s;
Array.blit env.v_stack 0 new_v 0 oldsize;
env.v_stack <- new_v;
Array.blit env.symb_start_stack 0 new_start 0 oldsize;
env.symb_start_stack <- new_start;
Array.blit env.symb_end_stack 0 new_end 0 oldsize;
env.symb_end_stack <- new_end;
env.stacksize <- newsize
let clear_parser() =
Array.fill env.v_stack 0 env.stacksize (Obj.repr ());
env.lval <- Obj.repr ()
let current_lookahead_fun = ref (fun (x: Obj.t) -> false)
let yyparse tables start lexer lexbuf =
let rec loop cmd arg =
match parse_engine tables env cmd arg with
Read_token ->
let t = Obj.repr(lexer lexbuf) in
env.symb_start <- lexbuf.lex_abs_pos + lexbuf.lex_start_pos;
env.symb_end <- lexbuf.lex_abs_pos + lexbuf.lex_curr_pos;
loop Token_read t
| Raise_parse_error ->
raise Parse_error
| Compute_semantic_action ->
let (action, value) =
try
(Semantic_action_computed, tables.actions.(env.rule_number) env)
with Parse_error ->
(Error_detected, Obj.repr ()) in
loop action value
| Grow_stacks_1 ->
grow_stacks(); loop Stacks_grown_1 (Obj.repr ())
| Grow_stacks_2 ->
grow_stacks(); loop Stacks_grown_2 (Obj.repr ())
| Call_error_function ->
tables.error_function "syntax error";
loop Error_detected (Obj.repr ()) in
let init_asp = env.asp
and init_sp = env.sp
and init_state = env.state
and init_curr_char = env.curr_char in
env.stackbase <- env.sp + 1;
env.curr_char <- start;
try
loop Start (Obj.repr ())
with exn ->
let curr_char = env.curr_char in
env.asp <- init_asp;
env.sp <- init_sp;
env.state <- init_state;
env.curr_char <- init_curr_char;
match exn with
YYexit v ->
Obj.magic v
| _ ->
current_lookahead_fun :=
(fun tok ->
if Obj.is_block tok
then tables.transl_block.(Obj.tag tok) = curr_char
else tables.transl_const.(Obj.magic tok) = curr_char);
raise exn
let peek_val env n =
Obj.magic env.v_stack.(env.asp - n)
let symbol_start () =
env.symb_start_stack.(env.asp - env.rule_len + 1)
let symbol_end () =
env.symb_end_stack.(env.asp)
let rhs_start n =
env.symb_start_stack.(env.asp - (env.rule_len - n))
let rhs_end n =
env.symb_end_stack.(env.asp - (env.rule_len - n))
let is_current_lookahead tok =
(!current_lookahead_fun)(Obj.repr tok)
let parse_error (msg: string) =
raise Parse_error
|
