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
   5  * License as published by the Free Software Foundation; either
   6  * version 2.1 of the License, or (at your option) any later version.
   7  *
   8  * This library is distributed in the hope that it will be useful,
   9  * but 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 02110-1301 USA
  16  */
  17
  18
  19 \f
  20 #ifdef HAVE_CONFIG_H
  21 # include <config.h>
  22 #endif
  23
  24 #include "libguile/_scm.h"
  25 #include "libguile/alist.h" /* for SCM_EXTEND_ENV (well...) */
  26 #include "libguile/eval.h"
  27 #include "libguile/ports.h"
  28 #include "libguile/print.h"
  29 #include "libguile/root.h"
  30 #include "libguile/smob.h"
  31 #include "libguile/deprecation.h"
  32
  33 #include "libguile/validate.h"
  34 #include "libguile/programs.h"
  35 #include "libguile/macros.h"
  36
  37 #include "libguile/private-options.h"
  38
  39 scm_t_bits scm_tc16_macro;
  40
  41
  42 static int
  43 macro_print (SCM macro, SCM port, scm_print_state *pstate)
  44 {
  45   SCM code = SCM_MACRO_CODE (macro);
  46   if (!SCM_CLOSUREP (code)
  47       || scm_is_false (scm_procedure_p (SCM_PRINT_CLOSURE))
  48       || scm_is_false (scm_printer_apply (SCM_PRINT_CLOSURE,
  49                                         macro, port, pstate)))
  50     {
  51       scm_puts ("#<", port);
  52
  53       if (SCM_MACRO_TYPE (macro) < 4 && SCM_MACRO_IS_EXTENDED (macro))
  54         scm_puts ("extended-", port);
  55
  56       if (!SCM_CLOSUREP (code) && !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_CLOSUREP (code) && SCM_PRINT_SOURCE_P)
  76         {
  77           SCM formals = SCM_CLOSURE_FORMALS (code);
  78           SCM env = SCM_ENV (code);
  79           SCM xenv = SCM_EXTEND_ENV (formals, SCM_EOL, env);
  80           SCM src = scm_i_unmemocopy_body (SCM_CODE (code), xenv);
  81           scm_putc (' ', port);
  82           scm_iprin1 (src, port, pstate);
  83         }
  84
  85       if (SCM_MACRO_IS_EXTENDED (macro))
  86         {
  87           scm_putc (' ', port);
  88           scm_write (SCM_SMOB_OBJECT_2 (macro), port);
  89           scm_putc (' ', port);
  90           scm_write (SCM_SMOB_OBJECT_3 (macro), port);
  91         }
  92
  93       scm_putc ('>', port);
  94     }
  95
  96   return 1;
  97 }
  98
  99 static SCM
 100 macro_mark (SCM macro)
 101 {
 102   if (SCM_MACRO_IS_EXTENDED (macro))
 103     { scm_gc_mark (SCM_SMOB_OBJECT_2 (macro));
 104       scm_gc_mark (SCM_SMOB_OBJECT_3 (macro));
 105     }
 106   return SCM_SMOB_OBJECT (macro);
 107 }
 108
 109 static SCM
 110 makmac (SCM code, scm_t_bits flags)
 111 {
 112   SCM z;
 113   SCM_NEWSMOB (z, scm_tc16_macro, SCM_UNPACK (code));
 114   SCM_SET_SMOB_FLAGS (z, flags);
 115   return z;
 116 }
 117
 118 /* Return a mmacro that is known to be one of guile's built in macros. */
 119 SCM
 120 scm_i_makbimacro (SCM code)
 121 #define FUNC_NAME "scm_i_makbimacro"
 122 {
 123   SCM_VALIDATE_PROC (1, code);
 124   return makmac (code, 3);
 125 }
 126 #undef FUNC_NAME
 127
 128
 129 SCM_DEFINE (scm_makmmacro, "procedure->memoizing-macro", 1, 0, 0,
 130            (SCM code),
 131             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 132             "appears as the first symbol in an expression, evaluates the\n"
 133             "result of applying @var{code} to the expression and the\n"
 134             "environment.\n\n"
 135             "@code{procedure->memoizing-macro} is the same as\n"
 136             "@code{procedure->macro}, except that the expression returned by\n"
 137             "@var{code} replaces the original macro expression in the memoized\n"
 138             "form of the containing code.")
 139 #define FUNC_NAME s_scm_makmmacro
 140 {
 141   SCM_VALIDATE_PROC (1, code);
 142   return makmac (code, 2);
 143 }
 144 #undef FUNC_NAME
 145
 146
 147 SCM_DEFINE (scm_makacro, "procedure->syntax", 1, 0, 0,
 148             (SCM code),
 149             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 150             "appears as the first symbol in an expression, returns the\n"
 151             "result of applying @var{code} to the expression and the\n"
 152             "environment.")
 153 #define FUNC_NAME s_scm_makacro
 154 {
 155   SCM_VALIDATE_PROC (1, code);
 156   return makmac (code, 0);
 157 }
 158 #undef FUNC_NAME
 159
 160
 161 #if SCM_ENABLE_DEPRECATED == 1
 162
 163 SCM_DEFINE (scm_makmacro, "procedure->macro", 1, 0, 0,
 164            (SCM code),
 165             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 166             "appears as the first symbol in an expression, evaluates the\n"
 167             "result of applying @var{code} to the expression and the\n"
 168             "environment.  For example:\n"
 169             "\n"
 170             "@lisp\n"
 171             "(define trace\n"
 172             "  (procedure->macro\n"
 173             "   (lambda (x env) `(set! ,(cadr x) (tracef ,(cadr x) ',(cadr x))))))\n\n"
 174             "(trace @i{foo}) @equiv{} (set! @i{foo} (tracef @i{foo} '@i{foo})).\n"
 175             "@end lisp")
 176 #define FUNC_NAME s_scm_makmacro
 177 {
 178   scm_c_issue_deprecation_warning
 179     ("The function procedure->macro is deprecated, and so are"
 180      " non-memoizing macros in general.  Use memoizing macros"
 181      " or r5rs macros instead.");
 182
 183   SCM_VALIDATE_PROC (1, code);
 184   return makmac (code, 1);
 185 }
 186 #undef FUNC_NAME
 187
 188 #endif
 189
 190 SCM_DEFINE (scm_make_syncase_macro, "make-syncase-macro", 2, 0, 0,
 191             (SCM type, SCM binding),
 192             "Return a @dfn{macro} that requires expansion by syntax-case.\n"
 193             "While users should not call this function, it is useful to know\n"
 194             "that syntax-case macros are represented as Guile primitive macros.")
 195 #define FUNC_NAME s_scm_make_syncase_macro
 196 {
 197   SCM z;
 198   SCM_VALIDATE_SYMBOL (1, type);
 199
 200   SCM_NEWSMOB3 (z, scm_tc16_macro, SCM_UNPACK (binding), SCM_UNPACK (type),
 201                 SCM_UNPACK (binding));
 202   SCM_SET_SMOB_FLAGS (z, 4 | SCM_F_MACRO_EXTENDED);
 203   return z;
 204 }
 205 #undef FUNC_NAME
 206
 207 SCM_DEFINE (scm_make_extended_syncase_macro, "make-extended-syncase-macro", 3, 0, 0,
 208             (SCM m, SCM type, SCM binding),
 209             "Extend a core macro @var{m} with a syntax-case binding.")
 210 #define FUNC_NAME s_scm_make_extended_syncase_macro
 211 {
 212   SCM z;
 213   SCM_VALIDATE_SMOB (1, m, macro);
 214   SCM_VALIDATE_SYMBOL (2, type);
 215
 216   SCM_NEWSMOB3 (z, scm_tc16_macro, SCM_SMOB_DATA (m), SCM_UNPACK (type),
 217                 SCM_UNPACK (binding));
 218   SCM_SET_SMOB_FLAGS (z, SCM_SMOB_FLAGS (m) | SCM_F_MACRO_EXTENDED);
 219   return z;
 220 }
 221 #undef FUNC_NAME
 222
 223
 224
 225 SCM_DEFINE (scm_macro_p, "macro?", 1, 0, 0,
 226             (SCM obj),
 227             "Return @code{#t} if @var{obj} is a regular macro, a memoizing macro or a\n"
 228             "syntax transformer.")
 229 #define FUNC_NAME s_scm_macro_p
 230 {
 231   return scm_from_bool (SCM_SMOB_PREDICATE (scm_tc16_macro, obj));
 232 }
 233 #undef FUNC_NAME
 234
 235
 236 SCM_SYMBOL (scm_sym_syntax, "syntax");
 237 #if SCM_ENABLE_DEPRECATED == 1
 238 SCM_SYMBOL (scm_sym_macro, "macro");
 239 #endif
 240 SCM_SYMBOL (scm_sym_mmacro, "macro!");
 241 SCM_SYMBOL (scm_sym_bimacro, "builtin-macro!");
 242 SCM_SYMBOL (scm_sym_syncase_macro, "syncase-macro");
 243
 244 SCM_DEFINE (scm_macro_type, "macro-type", 1, 0, 0,
 245             (SCM m),
 246             "Return one of the symbols @code{syntax}, @code{macro},\n"
 247             "@code{macro!}, or @code{syntax-case}, depending on whether\n"
 248             "@var{m} is a syntax transformer, a regular macro, a memoizing\n"
 249             "macro, or a syntax-case macro, respectively.  If @var{m} is\n"
 250             "not a macro, @code{#f} is returned.")
 251 #define FUNC_NAME s_scm_macro_type
 252 {
 253   if (!SCM_SMOB_PREDICATE (scm_tc16_macro, m))
 254     return SCM_BOOL_F;
 255   switch (SCM_MACRO_TYPE (m))
 256     {
 257     case 0: return scm_sym_syntax;
 258 #if SCM_ENABLE_DEPRECATED == 1
 259     case 1: return scm_sym_macro;
 260 #endif
 261     case 2: return scm_sym_mmacro;
 262     case 3: return scm_sym_bimacro;
 263     case 4: return scm_sym_syncase_macro;
 264     default: scm_wrong_type_arg (FUNC_NAME, 1, m);
 265     }
 266 }
 267 #undef FUNC_NAME
 268
 269
 270 SCM_DEFINE (scm_macro_name, "macro-name", 1, 0, 0,
 271             (SCM m),
 272             "Return the name of the macro @var{m}.")
 273 #define FUNC_NAME s_scm_macro_name
 274 {
 275   SCM_VALIDATE_SMOB (1, m, macro);
 276   if (scm_is_true (scm_procedure_p (SCM_SMOB_OBJECT (m))))
 277     return scm_procedure_name (SCM_SMOB_OBJECT (m));
 278   return SCM_BOOL_F;
 279 }
 280 #undef FUNC_NAME
 281
 282
 283 SCM_DEFINE (scm_macro_transformer, "macro-transformer", 1, 0, 0,
 284             (SCM m),
 285             "Return the transformer of the macro @var{m}.")
 286 #define FUNC_NAME s_scm_macro_transformer
 287 {
 288   SCM data;
 289
 290   SCM_VALIDATE_SMOB (1, m, macro);
 291   data = SCM_PACK (SCM_SMOB_DATA (m));
 292
 293   if (SCM_CLOSUREP (data) || SCM_PROGRAM_P (data))
 294     return data;
 295   else
 296     return SCM_BOOL_F;
 297 }
 298 #undef FUNC_NAME
 299
 300 SCM_DEFINE (scm_syncase_macro_type, "syncase-macro-type", 1, 0, 0,
 301             (SCM m),
 302             "Return the type of the macro @var{m}.")
 303 #define FUNC_NAME s_scm_syncase_macro_type
 304 {
 305   SCM_VALIDATE_SMOB (1, m, macro);
 306
 307   if (SCM_MACRO_IS_EXTENDED (m))
 308     return SCM_SMOB_OBJECT_2 (m);
 309   else
 310     return SCM_BOOL_F;
 311 }
 312 #undef FUNC_NAME
 313
 314 SCM_DEFINE (scm_syncase_macro_binding, "syncase-macro-binding", 1, 0, 0,
 315             (SCM m),
 316             "Return the binding of the macro @var{m}.")
 317 #define FUNC_NAME s_scm_syncase_macro_binding
 318 {
 319   SCM_VALIDATE_SMOB (1, m, macro);
 320
 321   if (SCM_MACRO_IS_EXTENDED (m))
 322     return SCM_SMOB_OBJECT_3 (m);
 323   else
 324     return SCM_BOOL_F;
 325 }
 326 #undef FUNC_NAME
 327
 328 SCM
 329 scm_make_synt (const char *name, SCM (*macroizer) (), SCM (*fcn)() )
 330 {
 331   SCM var = scm_c_define (name, SCM_UNDEFINED);
 332   SCM transformer = scm_c_make_subr (name, scm_tc7_subr_2, fcn);
 333   SCM_VARIABLE_SET (var, macroizer (transformer));
 334   return SCM_UNSPECIFIED;
 335 }
 336
 337 void
 338 scm_init_macros ()
 339 {
 340   scm_tc16_macro = scm_make_smob_type ("macro", 0);
 341   scm_set_smob_mark (scm_tc16_macro, macro_mark);
 342   scm_set_smob_print (scm_tc16_macro, macro_print);
 343 #include "libguile/macros.x"
 344 }
 345
 346 /*
 347   Local Variables:
 348   c-file-style: "gnu"
 349   End:
 350 */