libguile/macros.c

   1 /* Copyright (C) 1995,1996,1997,1998,2000,2001,2002,2003, 2006, 2008 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 macro_mark (SCM macro)
 102 {
 103   if (SCM_MACRO_IS_EXTENDED (macro))
 104     { scm_gc_mark (SCM_SMOB_OBJECT_2 (macro));
 105       scm_gc_mark (SCM_SMOB_OBJECT_3 (macro));
 106     }
 107   return SCM_SMOB_OBJECT (macro);
 108 }
 109
 110 static SCM
 111 makmac (SCM code, scm_t_bits flags)
 112 {
 113   SCM z;
 114   SCM_NEWSMOB (z, scm_tc16_macro, SCM_UNPACK (code));
 115   SCM_SET_SMOB_FLAGS (z, flags);
 116   return z;
 117 }
 118
 119 /* Return a mmacro that is known to be one of guile's built in macros. */
 120 SCM
 121 scm_i_makbimacro (SCM code)
 122 #define FUNC_NAME "scm_i_makbimacro"
 123 {
 124   SCM_VALIDATE_PROC (1, code);
 125   return makmac (code, 3);
 126 }
 127 #undef FUNC_NAME
 128
 129
 130 SCM_DEFINE (scm_makmmacro, "procedure->memoizing-macro", 1, 0, 0,
 131            (SCM code),
 132             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 133             "appears as the first symbol in an expression, evaluates the\n"
 134             "result of applying @var{code} to the expression and the\n"
 135             "environment.\n\n"
 136             "@code{procedure->memoizing-macro} is the same as\n"
 137             "@code{procedure->macro}, except that the expression returned by\n"
 138             "@var{code} replaces the original macro expression in the memoized\n"
 139             "form of the containing code.")
 140 #define FUNC_NAME s_scm_makmmacro
 141 {
 142   SCM_VALIDATE_PROC (1, code);
 143   return makmac (code, 2);
 144 }
 145 #undef FUNC_NAME
 146
 147
 148 SCM_DEFINE (scm_makacro, "procedure->syntax", 1, 0, 0,
 149             (SCM code),
 150             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 151             "appears as the first symbol in an expression, returns the\n"
 152             "result of applying @var{code} to the expression and the\n"
 153             "environment.")
 154 #define FUNC_NAME s_scm_makacro
 155 {
 156   SCM_VALIDATE_PROC (1, code);
 157   return makmac (code, 0);
 158 }
 159 #undef FUNC_NAME
 160
 161
 162 #if SCM_ENABLE_DEPRECATED == 1
 163
 164 SCM_DEFINE (scm_makmacro, "procedure->macro", 1, 0, 0,
 165            (SCM code),
 166             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 167             "appears as the first symbol in an expression, evaluates the\n"
 168             "result of applying @var{code} to the expression and the\n"
 169             "environment.  For example:\n"
 170             "\n"
 171             "@lisp\n"
 172             "(define trace\n"
 173             "  (procedure->macro\n"
 174             "   (lambda (x env) `(set! ,(cadr x) (tracef ,(cadr x) ',(cadr x))))))\n\n"
 175             "(trace @i{foo}) @equiv{} (set! @i{foo} (tracef @i{foo} '@i{foo})).\n"
 176             "@end lisp")
 177 #define FUNC_NAME s_scm_makmacro
 178 {
 179   scm_c_issue_deprecation_warning
 180     ("The function procedure->macro is deprecated, and so are"
 181      " non-memoizing macros in general.  Use memoizing macros"
 182      " or r5rs macros instead.");
 183
 184   SCM_VALIDATE_PROC (1, code);
 185   return makmac (code, 1);
 186 }
 187 #undef FUNC_NAME
 188
 189 #endif
 190
 191 SCM_DEFINE (scm_make_syncase_macro, "make-syncase-macro", 2, 0, 0,
 192             (SCM type, SCM binding),
 193             "Return a @dfn{macro} that requires expansion by syntax-case.\n"
 194             "While users should not call this function, it is useful to know\n"
 195             "that syntax-case macros are represented as Guile primitive macros.")
 196 #define FUNC_NAME s_scm_make_syncase_macro
 197 {
 198   SCM z;
 199   SCM_VALIDATE_SYMBOL (1, type);
 200
 201   SCM_NEWSMOB3 (z, scm_tc16_macro, SCM_UNPACK (binding), SCM_UNPACK (type),
 202                 SCM_UNPACK (binding));
 203   SCM_SET_SMOB_FLAGS (z, 4 | SCM_F_MACRO_EXTENDED);
 204   return z;
 205 }
 206 #undef FUNC_NAME
 207
 208 SCM_DEFINE (scm_make_extended_syncase_macro, "make-extended-syncase-macro", 3, 0, 0,
 209             (SCM m, SCM type, SCM binding),
 210             "Extend a core macro @var{m} with a syntax-case binding.")
 211 #define FUNC_NAME s_scm_make_extended_syncase_macro
 212 {
 213   SCM z;
 214   SCM_VALIDATE_SMOB (1, m, macro);
 215   SCM_VALIDATE_SYMBOL (2, type);
 216
 217   SCM_NEWSMOB3 (z, scm_tc16_macro, SCM_SMOB_DATA (m), SCM_UNPACK (type),
 218                 SCM_UNPACK (binding));
 219   SCM_SET_SMOB_FLAGS (z, SCM_SMOB_FLAGS (m) | SCM_F_MACRO_EXTENDED);
 220   return z;
 221 }
 222 #undef FUNC_NAME
 223
 224
 225
 226 SCM_DEFINE (scm_macro_p, "macro?", 1, 0, 0,
 227             (SCM obj),
 228             "Return @code{#t} if @var{obj} is a regular macro, a memoizing macro, a\n"
 229             "syntax transformer, or a syntax-case macro.")
 230 #define FUNC_NAME s_scm_macro_p
 231 {
 232   return scm_from_bool (SCM_SMOB_PREDICATE (scm_tc16_macro, obj));
 233 }
 234 #undef FUNC_NAME
 235
 236
 237 SCM_SYMBOL (scm_sym_syntax, "syntax");
 238 #if SCM_ENABLE_DEPRECATED == 1
 239 SCM_SYMBOL (scm_sym_macro, "macro");
 240 #endif
 241 SCM_SYMBOL (scm_sym_mmacro, "macro!");
 242 SCM_SYMBOL (scm_sym_bimacro, "builtin-macro!");
 243 SCM_SYMBOL (scm_sym_syncase_macro, "syncase-macro");
 244
 245 SCM_DEFINE (scm_macro_type, "macro-type", 1, 0, 0,
 246             (SCM m),
 247             "Return one of the symbols @code{syntax}, @code{macro},\n"
 248             "@code{macro!}, or @code{syntax-case}, depending on whether\n"
 249             "@var{m} is a syntax transformer, a regular macro, a memoizing\n"
 250             "macro, or a syntax-case macro, respectively.  If @var{m} is\n"
 251             "not a macro, @code{#f} is returned.")
 252 #define FUNC_NAME s_scm_macro_type
 253 {
 254   if (!SCM_SMOB_PREDICATE (scm_tc16_macro, m))
 255     return SCM_BOOL_F;
 256   switch (SCM_MACRO_TYPE (m))
 257     {
 258     case 0: return scm_sym_syntax;
 259 #if SCM_ENABLE_DEPRECATED == 1
 260     case 1: return scm_sym_macro;
 261 #endif
 262     case 2: return scm_sym_mmacro;
 263     case 3: return scm_sym_bimacro;
 264     case 4: return scm_sym_syncase_macro;
 265     default: scm_wrong_type_arg (FUNC_NAME, 1, m);
 266     }
 267 }
 268 #undef FUNC_NAME
 269
 270
 271 SCM_DEFINE (scm_macro_name, "macro-name", 1, 0, 0,
 272             (SCM m),
 273             "Return the name of the macro @var{m}.")
 274 #define FUNC_NAME s_scm_macro_name
 275 {
 276   SCM_VALIDATE_SMOB (1, m, macro);
 277   if (scm_is_true (scm_procedure_p (SCM_SMOB_OBJECT (m))))
 278     return scm_procedure_name (SCM_SMOB_OBJECT (m));
 279   return SCM_BOOL_F;
 280 }
 281 #undef FUNC_NAME
 282
 283
 284 SCM_DEFINE (scm_macro_transformer, "macro-transformer", 1, 0, 0,
 285             (SCM m),
 286             "Return the transformer of the macro @var{m}.")
 287 #define FUNC_NAME s_scm_macro_transformer
 288 {
 289   SCM data;
 290
 291   SCM_VALIDATE_SMOB (1, m, macro);
 292   data = SCM_PACK (SCM_SMOB_DATA (m));
 293
 294   if (SCM_CLOSUREP (data) || SCM_PROGRAM_P (data))
 295     return data;
 296   else
 297     return SCM_BOOL_F;
 298 }
 299 #undef FUNC_NAME
 300
 301 SCM_DEFINE (scm_syncase_macro_type, "syncase-macro-type", 1, 0, 0,
 302             (SCM m),
 303             "Return the type of the macro @var{m}.")
 304 #define FUNC_NAME s_scm_syncase_macro_type
 305 {
 306   SCM_VALIDATE_SMOB (1, m, macro);
 307
 308   if (SCM_MACRO_IS_EXTENDED (m))
 309     return SCM_SMOB_OBJECT_2 (m);
 310   else
 311     return SCM_BOOL_F;
 312 }
 313 #undef FUNC_NAME
 314
 315 SCM_DEFINE (scm_syncase_macro_binding, "syncase-macro-binding", 1, 0, 0,
 316             (SCM m),
 317             "Return the binding of the macro @var{m}.")
 318 #define FUNC_NAME s_scm_syncase_macro_binding
 319 {
 320   SCM_VALIDATE_SMOB (1, m, macro);
 321
 322   if (SCM_MACRO_IS_EXTENDED (m))
 323     return SCM_SMOB_OBJECT_3 (m);
 324   else
 325     return SCM_BOOL_F;
 326 }
 327 #undef FUNC_NAME
 328
 329 SCM
 330 scm_make_synt (const char *name, SCM (*macroizer) (), SCM (*fcn)() )
 331 {
 332   SCM var = scm_c_define (name, SCM_UNDEFINED);
 333   SCM transformer = scm_c_make_subr (name, scm_tc7_subr_2, fcn);
 334   SCM_VARIABLE_SET (var, macroizer (transformer));
 335   return SCM_UNSPECIFIED;
 336 }
 337
 338 void
 339 scm_init_macros ()
 340 {
 341   scm_tc16_macro = scm_make_smob_type ("macro", 0);
 342   scm_set_smob_mark (scm_tc16_macro, macro_mark);
 343   scm_set_smob_print (scm_tc16_macro, macro_print);
 344 #include "libguile/macros.x"
 345 }
 346
 347 /*
 348   Local Variables:
 349   c-file-style: "gnu"
 350   End:
 351 */