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_SET_SUBRF(x, v) (SCM_SET_CELL_WORD_1 ((x), (v)))
  37 #define SCM_DSUBRF(x) ((double (*)()) SCM_CELL_WORD_1 (x))
  38 #define SCM_SUBR_PROPS(x) (SCM_SUBR_META_INFO (x) [1])
  39 #define SCM_SUBR_GENERIC(x) ((SCM *) SCM_CELL_WORD_2 (x))
  40 #define SCM_SET_SUBR_GENERIC(x, g) (*((SCM *) SCM_CELL_WORD_2 (x)) = (g))
  41 #define SCM_SET_SUBR_GENERIC_LOC(x, g) (SCM_SET_CELL_WORD_2 (x, (scm_t_bits) g))
  42
  43 #define SCM_CCLO_LENGTH(x) (SCM_CELL_WORD_0 (x) >> 8)
  44 #define SCM_MAKE_CCLO_TAG(v)  (((v) << 8) + scm_tc7_cclo)
  45 #define SCM_SET_CCLO_LENGTH(x, v) (SCM_SET_CELL_WORD_0 ((x), SCM_MAKE_CCLO_TAG(v)))
  46 #define SCM_CCLO_BASE(x) ((scm_t_bits *) SCM_CELL_WORD_1 (x))
  47 #define SCM_SET_CCLO_BASE(x, v) (SCM_SET_CELL_WORD_1 ((x), (v)))
  48
  49 #define SCM_CCLO_REF(x, i) (SCM_PACK (SCM_CCLO_BASE (x) [i]))
  50 #define SCM_CCLO_SET(x, i, v) (SCM_CCLO_BASE (x) [i] = SCM_UNPACK (v))
  51
  52 #define SCM_CCLO_SUBR(x) (SCM_CCLO_REF ((x), 0))
  53 #define SCM_SET_CCLO_SUBR(x, v) (SCM_CCLO_SET ((x), 0, (v)))
  54
  55 /* Closures
  56  */
  57
  58 #define SCM_CLOSUREP(x) (!SCM_IMP(x) && (SCM_TYP3 (x) == scm_tc3_closure))
  59 #define SCM_CLOSCAR(x) SCM_PACK (SCM_CELL_WORD_0 (x) - scm_tc3_closure)
  60 #define SCM_CODE(x) SCM_CAR (SCM_CLOSCAR (x))
  61 #define SCM_CLOSURE_FORMALS(x) SCM_CAR (SCM_CODE (x))
  62 #define SCM_CLOSURE_BODY(x) SCM_CDR (SCM_CODE (x))
  63 #define SCM_PROCPROPS(x) SCM_CDR (SCM_CLOSCAR (x))
  64 #define SCM_SETPROCPROPS(x, p) SCM_SETCDR (SCM_CLOSCAR (x), p)
  65 #define SCM_SETCODE(x, e) (SCM_SET_CELL_WORD_0 (x, SCM_UNPACK (scm_cons ((e), SCM_EOL)) \
  66                            + scm_tc3_closure))
  67 #define SCM_ENV(x) SCM_CELL_OBJECT_1 (x)
  68 #define SCM_SETENV(x, e) SCM_SET_CELL_OBJECT_1 ((x), (e))
  69 #define SCM_TOP_LEVEL(ENV)  (scm_is_null (ENV) || (scm_is_true (scm_procedure_p (SCM_CAR (ENV)))))
  70
  71 /* Procedure-with-setter
  72
  73    Four representations for procedure-with-setters were
  74    considered before selecting this one:
  75
  76    1. A closure where the CODE and ENV slots are used to represent
  77    the getter and a new SETTER slot is used for the setter.  The
  78    original getter is stored as a `getter' procedure property.  For
  79    closure getters, the CODE and ENV slots contains a copy of the
  80    getter's CODE and ENV slots.  For subr getters, the CODE contains
  81    a call to the subr.
  82
  83    2. A compiled closure with a call to the getter in the cclo
  84    procedure.  The getter and setter are stored in slots 1 and 2.
  85
  86    3. An entity (i.e. a struct with an associated procedure) with a
  87    call to the getter in the entity procedure and the setter stored
  88    in slot 0.  The original getter is stored in slot 1.
  89
  90    4. A new primitive procedure type supported in the evaluator.  The
  91    getter and setter are stored in a GETTER and SETTER slot.  A call
  92    to this procedure type results in a retrieval of the getter and a
  93    jump back to the correct eval dispatcher.
  94
  95    Representation 4 was selected because of efficiency and
  96    simplicity.
  97
  98    Rep 1 has the advantage that there is zero penalty for closure
  99    getters, but primitive getters will get considerable overhead
 100    because the procedure-with-getter will be a closure which calls
 101    the getter.
 102
 103    Rep 3 has the advantage that a GOOPS accessor can be a subclass of
 104    <procedure-with-setter>, but together with rep 2 it suffers from a
 105    three level dispatch for non-GOOPS getters:
 106
 107      cclo/struct --> dispatch proc --> getter
 108
 109    This is because the dispatch procedure must take an extra initial
 110    argument (cclo for rep 2, struct for rep 3).
 111
 112    Rep 4 has the single disadvantage that it uses up one tc7 type
 113    code, but the plan for uniform vectors will very likely free tc7
 114    codes, so this is probably no big problem.  Also note that the
 115    GETTER and SETTER slots can live directly on the heap, using the
 116    new four-word cells.  */
 117
 118 #define SCM_PROCEDURE_WITH_SETTER_P(obj) (!SCM_IMP(obj) && (SCM_TYP7 (obj) == scm_tc7_pws))
 119 #define SCM_PROCEDURE(obj) SCM_CELL_OBJECT_1 (obj)
 120 #define SCM_SETTER(obj) SCM_CELL_OBJECT_2 (obj)
 121
 122
 123 \f
 124
 125 SCM_API void scm_free_subr_entry (SCM subr);
 126 SCM_API SCM scm_c_make_subr (const char *name, long type, SCM (*fcn)());
 127 SCM_API SCM scm_c_make_subr_with_generic (const char *name, long type,
 128                                           SCM (*fcn)(), SCM *gf);
 129 SCM_API SCM scm_c_define_subr (const char *name, long type, SCM (*fcn)());
 130 SCM_API SCM scm_c_define_subr_with_generic (const char *name, long type,
 131                                             SCM (*fcn)(), SCM *gf);
 132 SCM_API SCM scm_makcclo (SCM proc, size_t len);
 133 SCM_API SCM scm_procedure_p (SCM obj);
 134 SCM_API SCM scm_closure_p (SCM obj);
 135 SCM_API SCM scm_thunk_p (SCM obj);
 136 SCM_API int scm_subr_p (SCM obj);
 137 SCM_API SCM scm_procedure_documentation (SCM proc);
 138 SCM_API SCM scm_procedure_with_setter_p (SCM obj);
 139 SCM_API SCM scm_make_procedure_with_setter (SCM procedure, SCM setter);
 140 SCM_API SCM scm_procedure (SCM proc);
 141 SCM_API SCM scm_setter (SCM proc);
 142 SCM_INTERNAL void scm_init_procs (void);
 143
 144 #ifdef GUILE_DEBUG
 145 SCM_API SCM scm_make_cclo (SCM proc, SCM len);
 146 #endif /*GUILE_DEBUG*/
 147
 148 #endif  /* SCM_PROCS_H */
 149
 150 /*
 151   Local Variables:
 152   c-file-style: "gnu"
 153   End:
 154 */