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
|
/*
Copyright (C) 1994 M. Hagiya, W. Schelter, T. Yuasa
This file is part of GNU Common Lisp, herein referred to as GCL
GCL is free software; you can redistribute it and/or modify it under
the terms of the GNU LIBRARY GENERAL PUBLIC LICENSE as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GCL is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
License for more details.
You should have received a copy of the GNU Library General Public License
along with GCL; see the file COPYING. If not, write to the Free Software
Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
catch.c
dynamic non-local exit
*/
#include "include.h"
static void
FFN(Fcatch)(VOL object args)
{
object *top = vs_top;
if (endp(args))
FEtoo_few_argumentsF(args);
eval(MMcar(args));
vs_top = top;
vs_push(vs_base[0]);
frs_push(FRS_CATCH, vs_base[0]);
if (nlj_active)
nlj_active = FALSE;
else
Fprogn(MMcdr(args));
frs_pop();
}
DEFUN_NEW("ERROR-SET",object,fSerror_set,SI
,1,1,NONE,OO,OO,OO,OO,(volatile object x0),
"Evaluates the FORM in the null environment. If the evaluation \
of the FORM has successfully completed, SI:ERROR-SET returns NIL as the first \
value and the result of the evaluation as the rest of the values. If, in the \
course of the evaluation, a non-local jump from the FORM is atempted, \
SI:ERROR-SET traps the jump and returns the corresponding jump tag as its \
value.")
{
object *old_lex = lex_env;
/* 1 args */
vs_push(Cnil);
frs_push(FRS_CATCHALL, Cnil);
if (nlj_active) {
nlj_active = FALSE;
x0 = nlj_tag;
frs_pop();
lex_env = old_lex;
RETURN1(x0);
} else {
lex_env = vs_top;
vs_push(Cnil);
vs_push(Cnil);
vs_push(Cnil);
x0 = Ieval(x0);
}
frs_pop();
lex_env = old_lex;
{int i = fcall.nvalues;
if (i+1>=sizeof(fcall.values)/sizeof(*fcall.values))
FEerror("Too many function call values",0);
while (i > 0)
{ fcall.values[i+1] = fcall.values[i];
i--;}
fcall.nvalues++;
fcall.values[1] = x0;}
return Cnil;
}
static void
FFN(Funwind_protect)(VOL object args)
{
object *top = vs_top;
object *value_top;
if (endp(args))
FEtoo_few_argumentsF(args);
frs_push(FRS_PROTECT, Cnil);
if (nlj_active) {
object tag = nlj_tag;
frame_ptr fr = nlj_fr;
value_top = vs_top;
vs_top = top;
while(vs_base<value_top) {
vs_push(vs_base[0]);
vs_base++;
}
value_top = vs_top;
nlj_active = FALSE;
frs_pop();
Fprogn(MMcdr(args));
vs_base = top;
vs_top = value_top;
if (vs_top == vs_base) vs_base[0] = Cnil;
unwind(fr, tag);
/* never reached */
} else {
eval(MMcar(args));
frs_pop();
value_top = vs_top;
vs_top = top;
while(vs_base<value_top) {
vs_push(vs_base[0]);
vs_base++;
}
value_top = vs_top;
Fprogn(MMcdr(args));
vs_base = top;
vs_top = value_top;
if (vs_top == vs_base) vs_base[0] = Cnil;
}
}
static void
FFN(Fthrow)(object args)
{
object *top = vs_top;
object tag;
frame_ptr fr;
if (endp(args) || endp(MMcdr(args)))
FEtoo_few_argumentsF(args);
if (!endp(MMcddr(args)))
FEtoo_many_argumentsF(args);
eval(MMcar(args));
vs_top = top;
tag = vs_base[0];
vs_push(tag);
fr = frs_sch_catch(tag);
if (fr == NULL)
FEerror("~S is an undefined tag.", 1, tag);
eval(MMcadr(args));
unwind(fr, tag);
/* never reached */
}
void
gcl_init_catch(void)
{
make_special_form("CATCH", Fcatch);
make_special_form("UNWIND-PROTECT", Funwind_protect);
make_special_form("THROW", Fthrow);
}
|