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ce212434 GH |
1 | /* Copyright (C) 2000 Free Software Foundation, Inc. |
2 | * | |
3 | * This program is free software; you can redistribute it and/or modify | |
4 | * it under the terms of the GNU General Public License as published by | |
5 | * the Free Software Foundation; either version 2, or (at your option) | |
6 | * any later version. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | * GNU General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License | |
14 | * along with this software; see the file COPYING. If not, write to | |
15 | * the Free Software Foundation, Inc., 59 Temple Place, Suite 330, | |
16 | * Boston, MA 02111-1307 USA | |
17 | * | |
18 | * As a special exception, the Free Software Foundation gives permission | |
19 | * for additional uses of the text contained in its release of GUILE. | |
20 | * | |
21 | * The exception is that, if you link the GUILE library with other files | |
22 | * to produce an executable, this does not by itself cause the | |
23 | * resulting executable to be covered by the GNU General Public License. | |
24 | * Your use of that executable is in no way restricted on account of | |
25 | * linking the GUILE library code into it. | |
26 | * | |
27 | * This exception does not however invalidate any other reasons why | |
28 | * the executable file might be covered by the GNU General Public License. | |
29 | * | |
30 | * This exception applies only to the code released by the | |
31 | * Free Software Foundation under the name GUILE. If you copy | |
32 | * code from other Free Software Foundation releases into a copy of | |
33 | * GUILE, as the General Public License permits, the exception does | |
34 | * not apply to the code that you add in this way. To avoid misleading | |
35 | * anyone as to the status of such modified files, you must delete | |
36 | * this exception notice from them. | |
37 | * | |
38 | * If you write modifications of your own for GUILE, it is your choice | |
39 | * whether to permit this exception to apply to your modifications. | |
40 | * If you do not wish that, delete this exception notice. */ | |
41 | ||
42 | #include "libguile/_scm.h" | |
43 | #include "libguile/eval.h" | |
44 | #include "libguile/feature.h" | |
45 | #include "libguile/gc.h" | |
46 | #include "libguile/numbers.h" | |
47 | #include "libguile/ports.h" | |
48 | #include "libguile/root.h" | |
49 | #include "libguile/strings.h" | |
50 | #include "libguile/struct.h" | |
51 | #include "libguile/validate.h" | |
52 | ||
53 | #include "libguile/values.h" | |
54 | ||
55 | static SCM values_vtable; | |
56 | ||
57 | #define SCM_VALUESP(x) (SCM_STRUCTP (x)\ | |
58 | && SCM_EQ_P (scm_struct_vtable (x), values_vtable)) | |
59 | ||
60 | static SCM | |
61 | print_values (SCM obj, SCM pwps) | |
62 | { | |
63 | SCM values = scm_struct_ref (obj, SCM_INUM0); | |
64 | SCM port = SCM_PORT_WITH_PS_PORT (pwps); | |
65 | scm_print_state *ps = SCM_PRINT_STATE (SCM_PORT_WITH_PS_PS (pwps)); | |
66 | ||
67 | while (SCM_CONSP (values)) | |
68 | { | |
69 | scm_iprin1 (SCM_CAR (values), port, ps); | |
70 | values = SCM_CDR (values); | |
71 | if (SCM_CONSP (values)) | |
72 | scm_newline (port); | |
73 | } | |
74 | return SCM_UNSPECIFIED; | |
75 | } | |
76 | ||
77 | SCM_DEFINE (scm_values, "values", 0, 0, 1, | |
78 | (SCM args), | |
79 | "Delivers all of its arguments to its continuation. Except for\n" | |
647e35e2 MG |
80 | "continuations created by the @code{call-with-values} procedure,\n" |
81 | "all continuations take exactly one value. The effect of\n" | |
82 | "passing no value or more than one value to continuations that\n" | |
83 | "were not created by @code{call-with-values} is unspecified.") | |
ce212434 GH |
84 | #define FUNC_NAME s_scm_values |
85 | { | |
86 | long n; | |
87 | SCM result; | |
88 | ||
89 | SCM_VALIDATE_LIST_COPYLEN (1, args, n); | |
90 | if (n == 1) | |
91 | result = SCM_CAR (args); | |
92 | else | |
93 | { | |
94 | result = scm_make_struct (values_vtable, SCM_INUM0, | |
95 | scm_cons (args, SCM_EOL)); | |
96 | } | |
97 | ||
98 | return result; | |
99 | } | |
100 | #undef FUNC_NAME | |
101 | ||
102 | SCM_DEFINE (scm_call_with_values, "call-with-values", 2, 0, 0, | |
103 | (SCM producer, SCM consumer), | |
104 | "Calls its @var{producer} argument with no values and a\n" | |
105 | "continuation that, when passed some values, calls the\n" | |
106 | "@var{consumer} procedure with those values as arguments. The\n" | |
107 | "continuation for the call to @var{consumer} is the continuation\n" | |
647e35e2 | 108 | "of the call to @code{call-with-values}.\n\n" |
ce212434 GH |
109 | "@example\n" |
110 | "(call-with-values (lambda () (values 4 5))\n" | |
111 | " (lambda (a b) b))\n" | |
112 | " ==> 5\n\n" | |
113 | "@end example\n" | |
114 | "@example\n" | |
115 | "(call-with-values * -) ==> -1\n" | |
116 | "@end example") | |
117 | #define FUNC_NAME s_scm_call_with_values | |
118 | { | |
119 | SCM product; | |
120 | ||
121 | SCM_VALIDATE_PROC (1, producer); | |
122 | SCM_VALIDATE_PROC (2, consumer); | |
123 | ||
124 | product = scm_apply (producer, SCM_EOL, SCM_EOL); | |
125 | if (SCM_VALUESP (product)) | |
126 | product = scm_struct_ref (product, SCM_INUM0); | |
127 | else | |
128 | product = scm_cons (product, SCM_EOL); | |
129 | return scm_apply (consumer, product, SCM_EOL); | |
130 | } | |
131 | #undef FUNC_NAME | |
132 | ||
133 | void | |
134 | scm_init_values (void) | |
135 | { | |
136 | SCM print = scm_make_subr ("%print-values", scm_tc7_subr_2, print_values); | |
137 | ||
138 | values_vtable | |
139 | = scm_permanent_object (scm_make_vtable_vtable (scm_makfrom0str ("pr"), | |
140 | SCM_INUM0, SCM_EOL)); | |
141 | SCM_SET_STRUCT_PRINTER (values_vtable, print); | |
142 | ||
143 | scm_add_feature ("values"); | |
144 | ||
145 | #ifndef SCM_MAGIC_SNARFER | |
146 | #include "libguile/values.x" | |
147 | #endif | |
148 | } | |
149 | ||
150 | /* | |
151 | Local Variables: | |
152 | c-file-style: "gnu" | |
153 | End: | |
154 | */ |