libguile/procs.h

   1 /* classes: h_files */
   2
   3 #ifndef SCM_PROCS_H
   4 #define SCM_PROCS_H
   5
   6 /* Copyright (C) 1995,1996,1998,1999,2000,2001, 2006, 2008, 2009 Free Software Foundation, Inc.
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 \f
  24
  25 #include "libguile/__scm.h"
  26
  27 \f
  28
  29
  30 /* Subrs
  31  */
  32
  33 #define SCM_SUBR_META_INFO(x)  ((SCM *) SCM_CELL_WORD_3 (x))
  34 #define SCM_SNAME(x) (SCM_SUBR_META_INFO (x) [0])
  35 #define SCM_SUBRF(x) ((SCM (*)()) SCM_CELL_WORD_1 (x))
  36 #define SCM_DSUBRF(x) ((double (*)()) SCM_CELL_WORD_1 (x))
  37 #define SCM_SUBR_PROPS(x) (SCM_SUBR_META_INFO (x) [1])
  38 #define SCM_SUBR_GENERIC(x) ((SCM *) SCM_CELL_WORD_2 (x))
  39 #define SCM_SET_SUBR_GENERIC(x, g) (*((SCM *) SCM_CELL_WORD_2 (x)) = (g))
  40 #define SCM_SET_SUBR_GENERIC_LOC(x, g) (SCM_SET_CELL_WORD_2 (x, (scm_t_bits) g))
  41
  42 #define SCM_CCLO_LENGTH(x) (SCM_CELL_WORD_0 (x) >> 8)
  43 #define SCM_MAKE_CCLO_TAG(v)  (((v) << 8) + scm_tc7_cclo)
  44 #define SCM_SET_CCLO_LENGTH(x, v) (SCM_SET_CELL_WORD_0 ((x), SCM_MAKE_CCLO_TAG(v)))
  45 #define SCM_CCLO_BASE(x) ((scm_t_bits *) SCM_CELL_WORD_1 (x))
  46 #define SCM_SET_CCLO_BASE(x, v) (SCM_SET_CELL_WORD_1 ((x), (v)))
  47
  48 #define SCM_CCLO_REF(x, i) (SCM_PACK (SCM_CCLO_BASE (x) [i]))
  49 #define SCM_CCLO_SET(x, i, v) (SCM_CCLO_BASE (x) [i] = SCM_UNPACK (v))
  50
  51 #define SCM_CCLO_SUBR(x) (SCM_CCLO_REF ((x), 0))
  52 #define SCM_SET_CCLO_SUBR(x, v) (SCM_CCLO_SET ((x), 0, (v)))
  53
  54 /* Return the subr type corresponding to the given arity.  If the arity
  55    doesn't match that of a subr (e.g., too many arguments), then -1 is
  56    returned.  This has to be in sync with `create_gsubr ()'.  */
  57 #define SCM_SUBR_ARITY_TO_TYPE(req, opt, rest)  \
  58   ((rest) == 0                                  \
  59    ? ((opt) == 0                                \
  60       ? ((req) == 0                             \
  61          ? scm_tc7_subr_0                       \
  62          : ((req) == 1                          \
  63             ? scm_tc7_subr_1                    \
  64             : ((req) == 2                       \
  65                ? scm_tc7_subr_2                 \
  66                : ((req) == 3                    \
  67                   ? scm_tc7_subr_3              \
  68                   : -1))))                      \
  69       : ((opt) == 1                             \
  70          ? ((req) == 0                          \
  71             ? scm_tc7_subr_1o                   \
  72             : ((req) == 1                       \
  73                ? scm_tc7_subr_2o                \
  74                : -1))                           \
  75          : -1))                                 \
  76    : ((rest) == 1                               \
  77       ? ((opt) == 0                             \
  78          ? ((req) == 0                          \
  79             ? scm_tc7_lsubr                     \
  80             : ((req) == 2                       \
  81                ? scm_tc7_lsubr_2                \
  82                : -1))                           \
  83          : -1)                                  \
  84       : -1))
  85
  86
  87 \f
  88 /* Closures
  89  */
  90
  91 #define SCM_CLOSUREP(x) (!SCM_IMP(x) && (SCM_TYP3 (x) == scm_tc3_closure))
  92 #define SCM_CLOSCAR(x) SCM_PACK (SCM_CELL_WORD_0 (x) - scm_tc3_closure)
  93 #define SCM_CODE(x) SCM_CAR (SCM_CLOSCAR (x))
  94 #define SCM_CLOSURE_FORMALS(x) SCM_CAR (SCM_CODE (x))
  95 #define SCM_CLOSURE_BODY(x) SCM_CDR (SCM_CODE (x))
  96 #define SCM_PROCPROPS(x) SCM_CDR (SCM_CLOSCAR (x))
  97 #define SCM_SETPROCPROPS(x, p) SCM_SETCDR (SCM_CLOSCAR (x), p)
  98 #define SCM_ENV(x) SCM_CELL_OBJECT_1 (x)
  99 #define SCM_TOP_LEVEL(ENV)  (scm_is_null (ENV) || (scm_is_true (scm_procedure_p (SCM_CAR (ENV)))))
 100
 101 /* Procedure-with-setter
 102
 103    Four representations for procedure-with-setters were
 104    considered before selecting this one:
 105
 106    1. A closure where the CODE and ENV slots are used to represent
 107    the getter and a new SETTER slot is used for the setter.  The
 108    original getter is stored as a `getter' procedure property.  For
 109    closure getters, the CODE and ENV slots contains a copy of the
 110    getter's CODE and ENV slots.  For subr getters, the CODE contains
 111    a call to the subr.
 112
 113    2. A compiled closure with a call to the getter in the cclo
 114    procedure.  The getter and setter are stored in slots 1 and 2.
 115
 116    3. An entity (i.e. a struct with an associated procedure) with a
 117    call to the getter in the entity procedure and the setter stored
 118    in slot 0.  The original getter is stored in slot 1.
 119
 120    4. A new primitive procedure type supported in the evaluator.  The
 121    getter and setter are stored in a GETTER and SETTER slot.  A call
 122    to this procedure type results in a retrieval of the getter and a
 123    jump back to the correct eval dispatcher.
 124
 125    Representation 4 was selected because of efficiency and
 126    simplicity.
 127
 128    Rep 1 has the advantage that there is zero penalty for closure
 129    getters, but primitive getters will get considerable overhead
 130    because the procedure-with-getter will be a closure which calls
 131    the getter.
 132
 133    Rep 3 has the advantage that a GOOPS accessor can be a subclass of
 134    <procedure-with-setter>, but together with rep 2 it suffers from a
 135    three level dispatch for non-GOOPS getters:
 136
 137      cclo/struct --> dispatch proc --> getter
 138
 139    This is because the dispatch procedure must take an extra initial
 140    argument (cclo for rep 2, struct for rep 3).
 141
 142    Rep 4 has the single disadvantage that it uses up one tc7 type
 143    code, but the plan for uniform vectors will very likely free tc7
 144    codes, so this is probably no big problem.  Also note that the
 145    GETTER and SETTER slots can live directly on the heap, using the
 146    new four-word cells.  */
 147
 148 #define SCM_PROCEDURE_WITH_SETTER_P(obj) (!SCM_IMP(obj) && (SCM_TYP7 (obj) == scm_tc7_pws))
 149 #define SCM_PROCEDURE(obj) SCM_CELL_OBJECT_1 (obj)
 150 #define SCM_SETTER(obj) SCM_CELL_OBJECT_2 (obj)
 151
 152
 153 \f
 154
 155 SCM_API SCM scm_c_make_subr (const char *name, long type, SCM (*fcn)());
 156 SCM_API SCM scm_c_make_subr_with_generic (const char *name, long type,
 157                                           SCM (*fcn)(), SCM *gf);
 158 SCM_API SCM scm_c_define_subr (const char *name, long type, SCM (*fcn)());
 159 SCM_API SCM scm_c_define_subr_with_generic (const char *name, long type,
 160                                             SCM (*fcn)(), SCM *gf);
 161 SCM_API SCM scm_makcclo (SCM proc, size_t len);
 162 SCM_API SCM scm_procedure_p (SCM obj);
 163 SCM_API SCM scm_closure_p (SCM obj);
 164 SCM_API SCM scm_thunk_p (SCM obj);
 165 SCM_API int scm_subr_p (SCM obj);
 166 SCM_API SCM scm_procedure_documentation (SCM proc);
 167 SCM_API SCM scm_procedure_with_setter_p (SCM obj);
 168 SCM_API SCM scm_make_procedure_with_setter (SCM procedure, SCM setter);
 169 SCM_API SCM scm_procedure (SCM proc);
 170 SCM_API SCM scm_setter (SCM proc);
 171 SCM_INTERNAL void scm_init_procs (void);
 172
 173 #ifdef GUILE_DEBUG
 174 SCM_API SCM scm_make_cclo (SCM proc, SCM len);
 175 #endif /*GUILE_DEBUG*/
 176
 177 #endif  /* SCM_PROCS_H */
 178
 179 /*
 180   Local Variables:
 181   c-file-style: "gnu"
 182   End:
 183 */