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 #include "libguile/_scm.h"
  26 #include "libguile/alist.h" /* for SCM_EXTEND_ENV (well...) */
  27 #include "libguile/eval.h"
  28 #include "libguile/ports.h"
  29 #include "libguile/print.h"
  30 #include "libguile/root.h"
  31 #include "libguile/smob.h"
  32 #include "libguile/deprecation.h"
  33
  34 #include "libguile/validate.h"
  35 #include "libguile/programs.h"
  36 #include "libguile/macros.h"
  37
  38 #include "libguile/private-options.h"
  39
  40 scm_t_bits scm_tc16_macro;
  41
  42
  43 static int
  44 macro_print (SCM macro, SCM port, scm_print_state *pstate)
  45 {
  46   SCM code = SCM_MACRO_CODE (macro);
  47   if (!SCM_CLOSUREP (code)
  48       || scm_is_false (scm_procedure_p (SCM_PRINT_CLOSURE))
  49       || scm_is_false (scm_printer_apply (SCM_PRINT_CLOSURE,
  50                                         macro, port, pstate)))
  51     {
  52       scm_puts ("#<", port);
  53
  54       if (SCM_MACRO_TYPE (macro) < 4 && SCM_MACRO_IS_EXTENDED (macro))
  55         scm_puts ("extended-", port);
  56
  57       if (!SCM_CLOSUREP (code) && !SCM_PROGRAM_P (code))
  58         scm_puts ("primitive-", port);
  59
  60       if (SCM_MACRO_TYPE (macro) == 0)
  61         scm_puts ("syntax", port);
  62 #if SCM_ENABLE_DEPRECATED == 1
  63       if (SCM_MACRO_TYPE (macro) == 1)
  64         scm_puts ("macro", port);
  65 #endif
  66       if (SCM_MACRO_TYPE (macro) == 2)
  67         scm_puts ("macro!", port);
  68       if (SCM_MACRO_TYPE (macro) == 3)
  69         scm_puts ("builtin-macro!", port);
  70       if (SCM_MACRO_TYPE (macro) == 4)
  71         scm_puts ("syncase-macro", port);
  72
  73       scm_putc (' ', port);
  74       scm_iprin1 (scm_macro_name (macro), port, pstate);
  75
  76       if (SCM_CLOSUREP (code) && SCM_PRINT_SOURCE_P)
  77         {
  78           SCM formals = SCM_CLOSURE_FORMALS (code);
  79           SCM env = SCM_ENV (code);
  80           SCM xenv = SCM_EXTEND_ENV (formals, SCM_EOL, env);
  81           SCM src = scm_i_unmemocopy_body (SCM_CODE (code), xenv);
  82           scm_putc (' ', port);
  83           scm_iprin1 (src, port, pstate);
  84         }
  85
  86       if (SCM_MACRO_IS_EXTENDED (macro))
  87         {
  88           scm_putc (' ', port);
  89           scm_write (SCM_SMOB_OBJECT_2 (macro), port);
  90           scm_putc (' ', port);
  91           scm_write (SCM_SMOB_OBJECT_3 (macro), port);
  92         }
  93
  94       scm_putc ('>', port);
  95     }
  96
  97   return 1;
  98 }
  99
 100 static SCM
 101 makmac (SCM code, scm_t_bits flags)
 102 {
 103   SCM z;
 104   SCM_NEWSMOB (z, scm_tc16_macro, SCM_UNPACK (code));
 105   SCM_SET_SMOB_FLAGS (z, flags);
 106   return z;
 107 }
 108
 109 /* Return a mmacro that is known to be one of guile's built in macros. */
 110 SCM
 111 scm_i_makbimacro (SCM code)
 112 #define FUNC_NAME "scm_i_makbimacro"
 113 {
 114   SCM_VALIDATE_PROC (1, code);
 115   return makmac (code, 3);
 116 }
 117 #undef FUNC_NAME
 118
 119
 120 SCM_DEFINE (scm_makmmacro, "procedure->memoizing-macro", 1, 0, 0,
 121            (SCM code),
 122             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 123             "appears as the first symbol in an expression, evaluates the\n"
 124             "result of applying @var{code} to the expression and the\n"
 125             "environment.\n\n"
 126             "@code{procedure->memoizing-macro} is the same as\n"
 127             "@code{procedure->macro}, except that the expression returned by\n"
 128             "@var{code} replaces the original macro expression in the memoized\n"
 129             "form of the containing code.")
 130 #define FUNC_NAME s_scm_makmmacro
 131 {
 132   SCM_VALIDATE_PROC (1, code);
 133   return makmac (code, 2);
 134 }
 135 #undef FUNC_NAME
 136
 137
 138 SCM_DEFINE (scm_makacro, "procedure->syntax", 1, 0, 0,
 139             (SCM code),
 140             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 141             "appears as the first symbol in an expression, returns the\n"
 142             "result of applying @var{code} to the expression and the\n"
 143             "environment.")
 144 #define FUNC_NAME s_scm_makacro
 145 {
 146   SCM_VALIDATE_PROC (1, code);
 147   return makmac (code, 0);
 148 }
 149 #undef FUNC_NAME
 150
 151
 152 #if SCM_ENABLE_DEPRECATED == 1
 153
 154 SCM_DEFINE (scm_makmacro, "procedure->macro", 1, 0, 0,
 155            (SCM code),
 156             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 157             "appears as the first symbol in an expression, evaluates the\n"
 158             "result of applying @var{code} to the expression and the\n"
 159             "environment.  For example:\n"
 160             "\n"
 161             "@lisp\n"
 162             "(define trace\n"
 163             "  (procedure->macro\n"
 164             "   (lambda (x env) `(set! ,(cadr x) (tracef ,(cadr x) ',(cadr x))))))\n\n"
 165             "(trace @i{foo}) @equiv{} (set! @i{foo} (tracef @i{foo} '@i{foo})).\n"
 166             "@end lisp")
 167 #define FUNC_NAME s_scm_makmacro
 168 {
 169   scm_c_issue_deprecation_warning
 170     ("The function procedure->macro is deprecated, and so are"
 171      " non-memoizing macros in general.  Use memoizing macros"
 172      " or r5rs macros instead.");
 173
 174   SCM_VALIDATE_PROC (1, code);
 175   return makmac (code, 1);
 176 }
 177 #undef FUNC_NAME
 178
 179 #endif
 180
 181 SCM_DEFINE (scm_make_syncase_macro, "make-syncase-macro", 2, 0, 0,
 182             (SCM type, SCM binding),
 183             "Return a @dfn{macro} that requires expansion by syntax-case.\n"
 184             "While users should not call this function, it is useful to know\n"
 185             "that syntax-case macros are represented as Guile primitive macros.")
 186 #define FUNC_NAME s_scm_make_syncase_macro
 187 {
 188   SCM z;
 189   SCM_VALIDATE_SYMBOL (1, type);
 190
 191   SCM_NEWSMOB3 (z, scm_tc16_macro, SCM_UNPACK (binding), SCM_UNPACK (type),
 192                 SCM_UNPACK (binding));
 193   SCM_SET_SMOB_FLAGS (z, 4 | SCM_F_MACRO_EXTENDED);
 194   return z;
 195 }
 196 #undef FUNC_NAME
 197
 198 SCM_DEFINE (scm_make_extended_syncase_macro, "make-extended-syncase-macro", 3, 0, 0,
 199             (SCM m, SCM type, SCM binding),
 200             "Extend a core macro @var{m} with a syntax-case binding.")
 201 #define FUNC_NAME s_scm_make_extended_syncase_macro
 202 {
 203   SCM z;
 204   SCM_VALIDATE_SMOB (1, m, macro);
 205   SCM_VALIDATE_SYMBOL (2, type);
 206
 207   SCM_NEWSMOB3 (z, scm_tc16_macro, SCM_SMOB_DATA (m), SCM_UNPACK (type),
 208                 SCM_UNPACK (binding));
 209   SCM_SET_SMOB_FLAGS (z, SCM_SMOB_FLAGS (m) | SCM_F_MACRO_EXTENDED);
 210   return z;
 211 }
 212 #undef FUNC_NAME
 213
 214
 215
 216 SCM_DEFINE (scm_macro_p, "macro?", 1, 0, 0,
 217             (SCM obj),
 218             "Return @code{#t} if @var{obj} is a regular macro, a memoizing macro, a\n"
 219             "syntax transformer, or a syntax-case macro.")
 220 #define FUNC_NAME s_scm_macro_p
 221 {
 222   return scm_from_bool (SCM_SMOB_PREDICATE (scm_tc16_macro, obj));
 223 }
 224 #undef FUNC_NAME
 225
 226
 227 SCM_SYMBOL (scm_sym_syntax, "syntax");
 228 #if SCM_ENABLE_DEPRECATED == 1
 229 SCM_SYMBOL (scm_sym_macro, "macro");
 230 #endif
 231 SCM_SYMBOL (scm_sym_mmacro, "macro!");
 232 SCM_SYMBOL (scm_sym_bimacro, "builtin-macro!");
 233 SCM_SYMBOL (scm_sym_syncase_macro, "syncase-macro");
 234
 235 SCM_DEFINE (scm_macro_type, "macro-type", 1, 0, 0,
 236             (SCM m),
 237             "Return one of the symbols @code{syntax}, @code{macro},\n"
 238             "@code{macro!}, or @code{syntax-case}, depending on whether\n"
 239             "@var{m} is a syntax transformer, a regular macro, a memoizing\n"
 240             "macro, or a syntax-case macro, respectively.  If @var{m} is\n"
 241             "not a macro, @code{#f} is returned.")
 242 #define FUNC_NAME s_scm_macro_type
 243 {
 244   if (!SCM_SMOB_PREDICATE (scm_tc16_macro, m))
 245     return SCM_BOOL_F;
 246   switch (SCM_MACRO_TYPE (m))
 247     {
 248     case 0: return scm_sym_syntax;
 249 #if SCM_ENABLE_DEPRECATED == 1
 250     case 1: return scm_sym_macro;
 251 #endif
 252     case 2: return scm_sym_mmacro;
 253     case 3: return scm_sym_bimacro;
 254     case 4: return scm_sym_syncase_macro;
 255     default: scm_wrong_type_arg (FUNC_NAME, 1, m);
 256     }
 257 }
 258 #undef FUNC_NAME
 259
 260
 261 SCM_DEFINE (scm_macro_name, "macro-name", 1, 0, 0,
 262             (SCM m),
 263             "Return the name of the macro @var{m}.")
 264 #define FUNC_NAME s_scm_macro_name
 265 {
 266   SCM_VALIDATE_SMOB (1, m, macro);
 267   if (scm_is_true (scm_procedure_p (SCM_SMOB_OBJECT (m))))
 268     return scm_procedure_name (SCM_SMOB_OBJECT (m));
 269   return SCM_BOOL_F;
 270 }
 271 #undef FUNC_NAME
 272
 273
 274 SCM_DEFINE (scm_macro_transformer, "macro-transformer", 1, 0, 0,
 275             (SCM m),
 276             "Return the transformer of the macro @var{m}.")
 277 #define FUNC_NAME s_scm_macro_transformer
 278 {
 279   SCM data;
 280
 281   SCM_VALIDATE_SMOB (1, m, macro);
 282   data = SCM_PACK (SCM_SMOB_DATA (m));
 283
 284   if (SCM_CLOSUREP (data) || SCM_PROGRAM_P (data))
 285     return data;
 286   else
 287     return SCM_BOOL_F;
 288 }
 289 #undef FUNC_NAME
 290
 291 SCM_DEFINE (scm_syncase_macro_type, "syncase-macro-type", 1, 0, 0,
 292             (SCM m),
 293             "Return the type of the macro @var{m}.")
 294 #define FUNC_NAME s_scm_syncase_macro_type
 295 {
 296   SCM_VALIDATE_SMOB (1, m, macro);
 297
 298   if (SCM_MACRO_IS_EXTENDED (m))
 299     return SCM_SMOB_OBJECT_2 (m);
 300   else
 301     return SCM_BOOL_F;
 302 }
 303 #undef FUNC_NAME
 304
 305 SCM_DEFINE (scm_syncase_macro_binding, "syncase-macro-binding", 1, 0, 0,
 306             (SCM m),
 307             "Return the binding of the macro @var{m}.")
 308 #define FUNC_NAME s_scm_syncase_macro_binding
 309 {
 310   SCM_VALIDATE_SMOB (1, m, macro);
 311
 312   if (SCM_MACRO_IS_EXTENDED (m))
 313     return SCM_SMOB_OBJECT_3 (m);
 314   else
 315     return SCM_BOOL_F;
 316 }
 317 #undef FUNC_NAME
 318
 319 SCM
 320 scm_make_synt (const char *name, SCM (*macroizer) (), SCM (*fcn)() )
 321 {
 322   SCM var = scm_c_define (name, SCM_UNDEFINED);
 323   SCM transformer = scm_c_make_subr (name, scm_tc7_subr_2, fcn);
 324   SCM_VARIABLE_SET (var, macroizer (transformer));
 325   return SCM_UNSPECIFIED;
 326 }
 327
 328 void
 329 scm_init_macros ()
 330 {
 331   scm_tc16_macro = scm_make_smob_type ("macro", 0);
 332   scm_set_smob_print (scm_tc16_macro, macro_print);
 333 #include "libguile/macros.x"
 334 }
 335
 336 /*
 337   Local Variables:
 338   c-file-style: "gnu"
 339   End:
 340 */