libguile/macros.c

   1 /* Copyright (C) 1995,1996,1997,1998,2000,2001,2002,2003, 2006, 2008, 2009 Free Software Foundation, Inc.
   2  *
   3  * This library is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU Lesser General Public License
   5  * as published by the Free Software Foundation; either version 3 of
   6  * the License, or (at your option) any later version.
   7  *
   8  * This library is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * Lesser General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public
  14  * License along with this library; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  16  * 02110-1301 USA
  17  */
  18
  19
  20 \f
  21 #ifdef HAVE_CONFIG_H
  22 # include <config.h>
  23 #endif
  24
  25 #define SCM_BUILDING_DEPRECATED_CODE
  26
  27 #include "libguile/_scm.h"
  28 #include "libguile/alist.h" /* for SCM_EXTEND_ENV (well...) */
  29 #include "libguile/eval.h"
  30 #include "libguile/ports.h"
  31 #include "libguile/print.h"
  32 #include "libguile/root.h"
  33 #include "libguile/smob.h"
  34 #include "libguile/deprecation.h"
  35
  36 #include "libguile/validate.h"
  37 #include "libguile/programs.h"
  38 #include "libguile/macros.h"
  39
  40 #include "libguile/private-options.h"
  41
  42 scm_t_bits scm_tc16_macro;
  43
  44
  45 static int
  46 macro_print (SCM macro, SCM port, scm_print_state *pstate)
  47 {
  48   SCM code = SCM_MACRO_CODE (macro);
  49
  50   scm_puts ("#<", port);
  51
  52   if (SCM_MACRO_TYPE (macro) < 4 && SCM_MACRO_IS_EXTENDED (macro))
  53     scm_puts ("extended-", port);
  54
  55   /* FIXME: doesn't catch boot closures; but do we care? */
  56   if (!SCM_PROGRAM_P (code))
  57     scm_puts ("primitive-", port);
  58
  59   if (SCM_MACRO_TYPE (macro) == 0)
  60     scm_puts ("syntax", port);
  61 #if SCM_ENABLE_DEPRECATED == 1
  62   if (SCM_MACRO_TYPE (macro) == 1)
  63     scm_puts ("macro", port);
  64 #endif
  65   if (SCM_MACRO_TYPE (macro) == 2)
  66     scm_puts ("macro!", port);
  67   if (SCM_MACRO_TYPE (macro) == 3)
  68     scm_puts ("builtin-macro!", port);
  69   if (SCM_MACRO_TYPE (macro) == 4)
  70     scm_puts ("syncase-macro", port);
  71
  72   scm_putc (' ', port);
  73   scm_iprin1 (scm_macro_name (macro), port, pstate);
  74
  75   if (SCM_MACRO_IS_EXTENDED (macro))
  76     {
  77       scm_putc (' ', port);
  78       scm_write (SCM_SMOB_OBJECT_2 (macro), port);
  79       scm_putc (' ', port);
  80       scm_write (SCM_SMOB_OBJECT_3 (macro), port);
  81     }
  82
  83   scm_putc ('>', port);
  84
  85   return 1;
  86 }
  87
  88 static SCM
  89 makmac (SCM code, scm_t_bits flags)
  90 {
  91   SCM z;
  92   SCM_NEWSMOB (z, scm_tc16_macro, SCM_UNPACK (code));
  93   SCM_SET_SMOB_FLAGS (z, flags);
  94   return z;
  95 }
  96
  97 /* Return a mmacro that is known to be one of guile's built in macros. */
  98 SCM
  99 scm_i_makbimacro (SCM code)
 100 #define FUNC_NAME "scm_i_makbimacro"
 101 {
 102   SCM_VALIDATE_PROC (1, code);
 103   return makmac (code, 3);
 104 }
 105 #undef FUNC_NAME
 106
 107
 108 SCM_DEFINE (scm_makmmacro, "procedure->memoizing-macro", 1, 0, 0,
 109            (SCM code),
 110             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 111             "appears as the first symbol in an expression, evaluates the\n"
 112             "result of applying @var{code} to the expression and the\n"
 113             "environment.\n\n"
 114             "@code{procedure->memoizing-macro} is the same as\n"
 115             "@code{procedure->macro}, except that the expression returned by\n"
 116             "@var{code} replaces the original macro expression in the memoized\n"
 117             "form of the containing code.")
 118 #define FUNC_NAME s_scm_makmmacro
 119 {
 120   SCM_VALIDATE_PROC (1, code);
 121   return makmac (code, 2);
 122 }
 123 #undef FUNC_NAME
 124
 125
 126 SCM_DEFINE (scm_makacro, "procedure->syntax", 1, 0, 0,
 127             (SCM code),
 128             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 129             "appears as the first symbol in an expression, returns the\n"
 130             "result of applying @var{code} to the expression and the\n"
 131             "environment.")
 132 #define FUNC_NAME s_scm_makacro
 133 {
 134   SCM_VALIDATE_PROC (1, code);
 135   return makmac (code, 0);
 136 }
 137 #undef FUNC_NAME
 138
 139
 140 #if SCM_ENABLE_DEPRECATED == 1
 141
 142 SCM_DEFINE (scm_makmacro, "procedure->macro", 1, 0, 0,
 143            (SCM code),
 144             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 145             "appears as the first symbol in an expression, evaluates the\n"
 146             "result of applying @var{code} to the expression and the\n"
 147             "environment.  For example:\n"
 148             "\n"
 149             "@lisp\n"
 150             "(define trace\n"
 151             "  (procedure->macro\n"
 152             "   (lambda (x env) `(set! ,(cadr x) (tracef ,(cadr x) ',(cadr x))))))\n\n"
 153             "(trace @i{foo}) @equiv{} (set! @i{foo} (tracef @i{foo} '@i{foo})).\n"
 154             "@end lisp")
 155 #define FUNC_NAME s_scm_makmacro
 156 {
 157   scm_c_issue_deprecation_warning
 158     ("The function procedure->macro is deprecated, and so are"
 159      " non-memoizing macros in general.  Use memoizing macros"
 160      " or r5rs macros instead.");
 161
 162   SCM_VALIDATE_PROC (1, code);
 163   return makmac (code, 1);
 164 }
 165 #undef FUNC_NAME
 166
 167 #endif
 168
 169 SCM_DEFINE (scm_make_syncase_macro, "make-syncase-macro", 2, 0, 0,
 170             (SCM type, SCM binding),
 171             "Return a @dfn{macro} that requires expansion by syntax-case.\n"
 172             "While users should not call this function, it is useful to know\n"
 173             "that syntax-case macros are represented as Guile primitive macros.")
 174 #define FUNC_NAME s_scm_make_syncase_macro
 175 {
 176   SCM z;
 177   SCM_VALIDATE_SYMBOL (1, type);
 178
 179   SCM_NEWSMOB3 (z, scm_tc16_macro, SCM_UNPACK (binding), SCM_UNPACK (type),
 180                 SCM_UNPACK (binding));
 181   SCM_SET_SMOB_FLAGS (z, 4 | SCM_F_MACRO_EXTENDED);
 182   return z;
 183 }
 184 #undef FUNC_NAME
 185
 186 SCM_DEFINE (scm_make_extended_syncase_macro, "make-extended-syncase-macro", 3, 0, 0,
 187             (SCM m, SCM type, SCM binding),
 188             "Extend a core macro @var{m} with a syntax-case binding.")
 189 #define FUNC_NAME s_scm_make_extended_syncase_macro
 190 {
 191   SCM z;
 192   SCM_VALIDATE_SMOB (1, m, macro);
 193   SCM_VALIDATE_SYMBOL (2, type);
 194
 195   SCM_NEWSMOB3 (z, scm_tc16_macro, SCM_SMOB_DATA (m), SCM_UNPACK (type),
 196                 SCM_UNPACK (binding));
 197   SCM_SET_SMOB_FLAGS (z, SCM_SMOB_FLAGS (m) | SCM_F_MACRO_EXTENDED);
 198   return z;
 199 }
 200 #undef FUNC_NAME
 201
 202
 203
 204 SCM_DEFINE (scm_macro_p, "macro?", 1, 0, 0,
 205             (SCM obj),
 206             "Return @code{#t} if @var{obj} is a regular macro, a memoizing macro, a\n"
 207             "syntax transformer, or a syntax-case macro.")
 208 #define FUNC_NAME s_scm_macro_p
 209 {
 210   return scm_from_bool (SCM_SMOB_PREDICATE (scm_tc16_macro, obj));
 211 }
 212 #undef FUNC_NAME
 213
 214
 215 SCM_SYMBOL (scm_sym_syntax, "syntax");
 216 #if SCM_ENABLE_DEPRECATED == 1
 217 SCM_SYMBOL (scm_sym_macro, "macro");
 218 #endif
 219 SCM_SYMBOL (scm_sym_mmacro, "macro!");
 220 SCM_SYMBOL (scm_sym_bimacro, "builtin-macro!");
 221 SCM_SYMBOL (scm_sym_syncase_macro, "syncase-macro");
 222
 223 SCM_DEFINE (scm_macro_type, "macro-type", 1, 0, 0,
 224             (SCM m),
 225             "Return one of the symbols @code{syntax}, @code{macro},\n"
 226             "@code{macro!}, or @code{syntax-case}, depending on whether\n"
 227             "@var{m} is a syntax transformer, a regular macro, a memoizing\n"
 228             "macro, or a syntax-case macro, respectively.  If @var{m} is\n"
 229             "not a macro, @code{#f} is returned.")
 230 #define FUNC_NAME s_scm_macro_type
 231 {
 232   if (!SCM_SMOB_PREDICATE (scm_tc16_macro, m))
 233     return SCM_BOOL_F;
 234   switch (SCM_MACRO_TYPE (m))
 235     {
 236     case 0: return scm_sym_syntax;
 237 #if SCM_ENABLE_DEPRECATED == 1
 238     case 1: return scm_sym_macro;
 239 #endif
 240     case 2: return scm_sym_mmacro;
 241     case 3: return scm_sym_bimacro;
 242     case 4: return scm_sym_syncase_macro;
 243     default: scm_wrong_type_arg (FUNC_NAME, 1, m);
 244     }
 245 }
 246 #undef FUNC_NAME
 247
 248
 249 SCM_DEFINE (scm_macro_name, "macro-name", 1, 0, 0,
 250             (SCM m),
 251             "Return the name of the macro @var{m}.")
 252 #define FUNC_NAME s_scm_macro_name
 253 {
 254   SCM_VALIDATE_SMOB (1, m, macro);
 255   if (scm_is_true (scm_procedure_p (SCM_SMOB_OBJECT (m))))
 256     return scm_procedure_name (SCM_SMOB_OBJECT (m));
 257   return SCM_BOOL_F;
 258 }
 259 #undef FUNC_NAME
 260
 261
 262 SCM_DEFINE (scm_macro_transformer, "macro-transformer", 1, 0, 0,
 263             (SCM m),
 264             "Return the transformer of the macro @var{m}.")
 265 #define FUNC_NAME s_scm_macro_transformer
 266 {
 267   SCM data;
 268
 269   SCM_VALIDATE_SMOB (1, m, macro);
 270   data = SCM_PACK (SCM_SMOB_DATA (m));
 271
 272   if (scm_is_true (scm_procedure_p (data)))
 273     return data;
 274   else
 275     return SCM_BOOL_F;
 276 }
 277 #undef FUNC_NAME
 278
 279 SCM_DEFINE (scm_syncase_macro_type, "syncase-macro-type", 1, 0, 0,
 280             (SCM m),
 281             "Return the type of the macro @var{m}.")
 282 #define FUNC_NAME s_scm_syncase_macro_type
 283 {
 284   SCM_VALIDATE_SMOB (1, m, macro);
 285
 286   if (SCM_MACRO_IS_EXTENDED (m))
 287     return SCM_SMOB_OBJECT_2 (m);
 288   else
 289     return SCM_BOOL_F;
 290 }
 291 #undef FUNC_NAME
 292
 293 SCM_DEFINE (scm_syncase_macro_binding, "syncase-macro-binding", 1, 0, 0,
 294             (SCM m),
 295             "Return the binding of the macro @var{m}.")
 296 #define FUNC_NAME s_scm_syncase_macro_binding
 297 {
 298   SCM_VALIDATE_SMOB (1, m, macro);
 299
 300   if (SCM_MACRO_IS_EXTENDED (m))
 301     return SCM_SMOB_OBJECT_3 (m);
 302   else
 303     return SCM_BOOL_F;
 304 }
 305 #undef FUNC_NAME
 306
 307 SCM
 308 scm_make_synt (const char *name, SCM (*macroizer) (), SCM (*fcn)() )
 309 {
 310   SCM var = scm_c_define (name, SCM_UNDEFINED);
 311   SCM transformer = scm_c_make_gsubr (name, 2, 0, 0, fcn);
 312   SCM_VARIABLE_SET (var, macroizer (transformer));
 313   return SCM_UNSPECIFIED;
 314 }
 315
 316 void
 317 scm_init_macros ()
 318 {
 319   scm_tc16_macro = scm_make_smob_type ("macro", 0);
 320   scm_set_smob_print (scm_tc16_macro, macro_print);
 321 #include "libguile/macros.x"
 322 }
 323
 324 /*
 325   Local Variables:
 326   c-file-style: "gnu"
 327   End:
 328 */