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
|
/*
* Copyright © 2016 Keith Packard <keithp@keithp.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program 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
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
#include "ao_scheme.h"
int
lambda_size(void *addr)
{
(void) addr;
return sizeof (struct ao_scheme_lambda);
}
void
lambda_mark(void *addr)
{
struct ao_scheme_lambda *lambda = addr;
ao_scheme_poly_mark(lambda->code, 0);
ao_scheme_poly_mark(lambda->frame, 0);
}
void
lambda_move(void *addr)
{
struct ao_scheme_lambda *lambda = addr;
ao_scheme_poly_move(&lambda->code, 0);
ao_scheme_poly_move(&lambda->frame, 0);
}
const struct ao_scheme_type ao_scheme_lambda_type = {
.size = lambda_size,
.mark = lambda_mark,
.move = lambda_move,
.name = "lambda",
};
void
ao_scheme_lambda_write(ao_poly poly)
{
struct ao_scheme_lambda *lambda = ao_scheme_poly_lambda(poly);
struct ao_scheme_cons *cons = ao_scheme_poly_cons(lambda->code);
printf("(");
printf("%s", ao_scheme_args_name(lambda->args));
while (cons) {
printf(" ");
ao_scheme_poly_write(cons->car);
cons = ao_scheme_poly_cons(cons->cdr);
}
printf(")");
}
ao_poly
ao_scheme_lambda_alloc(struct ao_scheme_cons *code, int args)
{
struct ao_scheme_lambda *lambda;
ao_poly formal;
struct ao_scheme_cons *cons;
formal = ao_scheme_arg(code, 0);
while (formal != AO_SCHEME_NIL) {
switch (ao_scheme_poly_type(formal)) {
case AO_SCHEME_CONS:
cons = ao_scheme_poly_cons(formal);
if (ao_scheme_poly_type(cons->car) != AO_SCHEME_ATOM)
return ao_scheme_error(AO_SCHEME_INVALID, "formal %p is not atom", cons->car);
formal = cons->cdr;
break;
case AO_SCHEME_ATOM:
formal = AO_SCHEME_NIL;
break;
default:
return ao_scheme_error(AO_SCHEME_INVALID, "formal %p is not atom", formal);
}
}
ao_scheme_cons_stash(0, code);
lambda = ao_scheme_alloc(sizeof (struct ao_scheme_lambda));
code = ao_scheme_cons_fetch(0);
if (!lambda)
return AO_SCHEME_NIL;
lambda->type = AO_SCHEME_LAMBDA;
lambda->args = args;
lambda->code = ao_scheme_cons_poly(code);
lambda->frame = ao_scheme_frame_mark(ao_scheme_frame_current);
DBGI("build frame: "); DBG_POLY(lambda->frame); DBG("\n");
DBG_STACK();
return ao_scheme_lambda_poly(lambda);
}
ao_poly
ao_scheme_do_lambda(struct ao_scheme_cons *cons)
{
return ao_scheme_lambda_alloc(cons, AO_SCHEME_FUNC_LAMBDA);
}
ao_poly
ao_scheme_do_nlambda(struct ao_scheme_cons *cons)
{
return ao_scheme_lambda_alloc(cons, AO_SCHEME_FUNC_NLAMBDA);
}
ao_poly
ao_scheme_do_macro(struct ao_scheme_cons *cons)
{
return ao_scheme_lambda_alloc(cons, AO_SCHEME_FUNC_MACRO);
}
ao_poly
ao_scheme_lambda_eval(void)
{
struct ao_scheme_lambda *lambda = ao_scheme_poly_lambda(ao_scheme_v);
struct ao_scheme_cons *cons = ao_scheme_poly_cons(ao_scheme_stack->values);
struct ao_scheme_cons *code = ao_scheme_poly_cons(lambda->code);
ao_poly formals;
struct ao_scheme_frame *next_frame;
int args_wanted;
ao_poly varargs = AO_SCHEME_NIL;
int args_provided;
int f;
struct ao_scheme_cons *vals;
DBGI("lambda "); DBG_POLY(ao_scheme_lambda_poly(lambda)); DBG("\n");
args_wanted = 0;
for (formals = ao_scheme_arg(code, 0);
ao_scheme_is_pair(formals);
formals = ao_scheme_poly_cons(formals)->cdr)
++args_wanted;
if (formals != AO_SCHEME_NIL) {
if (ao_scheme_poly_type(formals) != AO_SCHEME_ATOM)
return ao_scheme_error(AO_SCHEME_INVALID, "bad lambda form");
varargs = formals;
}
/* Create a frame to hold the variables
*/
args_provided = ao_scheme_cons_length(cons) - 1;
if (varargs == AO_SCHEME_NIL) {
if (args_wanted != args_provided)
return ao_scheme_error(AO_SCHEME_INVALID, "need %d args, got %d", args_wanted, args_provided);
} else {
if (args_provided < args_wanted)
return ao_scheme_error(AO_SCHEME_INVALID, "need at least %d args, got %d", args_wanted, args_provided);
}
ao_scheme_poly_stash(1, varargs);
next_frame = ao_scheme_frame_new(args_wanted + (varargs != AO_SCHEME_NIL));
varargs = ao_scheme_poly_fetch(1);
if (!next_frame)
return AO_SCHEME_NIL;
/* Re-fetch all of the values in case something moved */
lambda = ao_scheme_poly_lambda(ao_scheme_v);
cons = ao_scheme_poly_cons(ao_scheme_stack->values);
code = ao_scheme_poly_cons(lambda->code);
formals = ao_scheme_arg(code, 0);
vals = ao_scheme_poly_cons(cons->cdr);
next_frame->prev = lambda->frame;
ao_scheme_frame_current = next_frame;
ao_scheme_stack->frame = ao_scheme_frame_poly(ao_scheme_frame_current);
for (f = 0; f < args_wanted; f++) {
struct ao_scheme_cons *arg = ao_scheme_poly_cons(formals);
DBGI("bind "); DBG_POLY(arg->car); DBG(" = "); DBG_POLY(vals->car); DBG("\n");
ao_scheme_frame_bind(next_frame, f, arg->car, vals->car);
formals = arg->cdr;
vals = ao_scheme_poly_cons(vals->cdr);
}
if (varargs) {
DBGI("bind "); DBG_POLY(varargs); DBG(" = "); DBG_POLY(ao_scheme_cons_poly(vals)); DBG("\n");
/*
* Bind the rest of the arguments to the final parameter
*/
ao_scheme_frame_bind(next_frame, f, varargs, ao_scheme_cons_poly(vals));
} else {
/*
* Mark the cons cells from the actuals as freed for immediate re-use, unless
* the actuals point into the source function (nlambdas and macros), or if the
* stack containing them was copied as a part of a continuation
*/
if (lambda->args == AO_SCHEME_FUNC_LAMBDA && !ao_scheme_stack_marked(ao_scheme_stack)) {
ao_scheme_stack->values = AO_SCHEME_NIL;
ao_scheme_cons_free(cons);
}
}
DBGI("eval frame: "); DBG_POLY(ao_scheme_frame_poly(next_frame)); DBG("\n");
DBG_STACK();
DBGI("eval code: "); DBG_POLY(code->cdr); DBG("\n");
return code->cdr;
}
|
