1 /* Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc.
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)
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.
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
18 * As a special exception, the Free Software Foundation gives permission
19 * for additional uses of the text contained in its release of GUILE.
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.
27 * This exception does not however invalidate any other reasons why
28 * the executable file might be covered by the GNU General Public License.
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.
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. */
42 /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
43 gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
59 prin_var (SCM exp
,SCM port
,scm_print_state
*pstate
)
61 scm_puts ("#<variable ", port
);
62 scm_intprint((int) exp
, 16, port
);
65 val_cell
= SCM_CDR(exp
);
66 if (SCM_CAR (val_cell
) != SCM_UNDEFINED
)
68 scm_puts (" name: ", port
);
69 scm_iprin1 (SCM_CAR (val_cell
), port
, pstate
);
71 scm_puts (" binding: ", port
);
72 scm_iprin1 (SCM_CDR (val_cell
), port
, pstate
);
86 var_equal (SCM var1
, SCM var2
)
88 return scm_equal_p (SCM_CDR (var1
), SCM_CDR (var2
));
91 int scm_tc16_variable
;
94 static SCM anonymous_variable_sym
;
98 make_vcell_variable (SCM vcell
)
100 SCM_RETURN_NEWSMOB (scm_tc16_variable
, vcell
);
103 SCM_DEFINE (scm_make_variable
, "make-variable", 1, 1, 0,
104 (SCM init
, SCM name_hint
),
105 "Return a variable object initialized to value INIT.\n"
106 "If given, uses NAME-HINT as its internal (debugging)\n"
107 "name, otherwise just treat it as an anonymous variable.\n"
108 "Remember, of course, that multiple bindings to the same\n"
109 "variable may exist, so NAME-HINT is just that---a hint.\n")
110 #define FUNC_NAME s_scm_make_variable
114 if (name_hint
== SCM_UNDEFINED
)
115 name_hint
= anonymous_variable_sym
;
117 SCM_NEWCELL(val_cell
);
119 SCM_SETCAR (val_cell
, name_hint
);
120 SCM_SETCDR (val_cell
, init
);
122 return make_vcell_variable (val_cell
);
127 SCM_DEFINE (scm_make_undefined_variable
, "make-undefined-variable", 0, 1, 0,
129 "Return a variable object initialized to an undefined value.\n"
130 "If given, uses NAME-HINT as its internal (debugging)\n"
131 "name, otherwise just treat it as an anonymous variable.\n"
132 "Remember, of course, that multiple bindings to the same\n"
133 "variable may exist, so NAME-HINT is just that---a hint.\n")
134 #define FUNC_NAME s_scm_make_undefined_variable
138 if (name_hint
== SCM_UNDEFINED
)
139 name_hint
= anonymous_variable_sym
;
143 SCM_SETCAR (vcell
, name_hint
);
144 SCM_SETCDR (vcell
, SCM_UNDEFINED
);
146 return make_vcell_variable (vcell
);
151 SCM_DEFINE (scm_variable_p
, "variable?", 1, 0, 0,
153 "Return #t iff OBJ is a variable object, else return #f\n")
154 #define FUNC_NAME s_scm_variable_p
156 return SCM_BOOL(SCM_VARIABLEP (obj
));
161 SCM_DEFINE (scm_variable_ref
, "variable-ref", 1, 0, 0,
163 "Dereference VAR and return its value.\n"
164 "VAR must be a variable object; see `make-variable' and\n"
165 "`make-undefined-variable'")
166 #define FUNC_NAME s_scm_variable_ref
168 SCM_VALIDATE_VARIABLE (1,var
);
169 return SCM_CDR (SCM_CDR (var
));
175 SCM_DEFINE (scm_variable_set_x
, "variable-set!", 2, 0, 0,
177 "Set the value of the variable VAR to VAL.\n"
178 "VAR must be a variable object, VAL can be any value.\n"
179 "Returns an unspecified value.\n")
180 #define FUNC_NAME s_scm_variable_set_x
182 SCM_VALIDATE_VARIABLE (1,var
);
183 SCM_SETCDR (SCM_CDR (var
), val
);
184 return SCM_UNSPECIFIED
;
189 SCM_DEFINE (scm_builtin_variable
, "builtin-variable", 1, 0, 0,
191 "Return the built-in variable with the name NAME.\n"
192 "NAME must be a symbol (not a string).\n"
193 "Then use `variable-ref' to access its value.\n")
194 #define FUNC_NAME s_scm_builtin_variable
199 SCM_VALIDATE_SYMBOL (1,name
);
200 vcell
= scm_sym2vcell (name
, SCM_BOOL_F
, SCM_BOOL_T
);
201 if (vcell
== SCM_BOOL_F
)
204 scm_intern_symbol (scm_symhash_vars
, name
);
205 var_slot
= scm_sym2ovcell (name
, scm_symhash_vars
);
208 if ( SCM_IMP (SCM_CDR (var_slot
))
209 || (SCM_VARVCELL (var_slot
) != vcell
))
210 SCM_SETCDR (var_slot
, make_vcell_variable (vcell
));
213 return SCM_CDR (var_slot
);
218 SCM_DEFINE (scm_variable_bound_p
, "variable-bound?", 1, 0, 0,
220 "Return #t iff VAR is bound to a value.\n"
221 "Throws an error if VAR is not a variable object.\n")
222 #define FUNC_NAME s_scm_variable_bound_p
224 SCM_VALIDATE_VARIABLE (1,var
);
225 return SCM_NEGATE_BOOL(SCM_UNBNDP (SCM_CDR (SCM_VARVCELL (var
))));
235 scm_tc16_variable
= scm_make_smob_type_mfpe ("variable", 0,
236 scm_markvar
, NULL
, prin_var
, var_equal
);
237 anonymous_variable_sym
= SCM_CAR (scm_sysintern ("anonymous-variable", SCM_UNDEFINED
));
238 #include "variable.x"