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/macros.h"
  35
  36 #include "libguile/private-options.h"
  37
  38 scm_t_bits scm_tc16_macro;
  39
  40
  41 static int
  42 macro_print (SCM macro, SCM port, scm_print_state *pstate)
  43 {
  44   SCM code = SCM_MACRO_CODE (macro);
  45   if (!SCM_CLOSUREP (code)
  46       || scm_is_false (scm_procedure_p (SCM_PRINT_CLOSURE))
  47       || scm_is_false (scm_printer_apply (SCM_PRINT_CLOSURE,
  48                                         macro, port, pstate)))
  49     {
  50       if (!SCM_CLOSUREP (code))
  51         scm_puts ("#<primitive-", port);
  52       else
  53         scm_puts ("#<", port);
  54
  55       if (SCM_MACRO_TYPE (macro) == 0)
  56         scm_puts ("syntax", port);
  57 #if SCM_ENABLE_DEPRECATED == 1
  58       if (SCM_MACRO_TYPE (macro) == 1)
  59         scm_puts ("macro", port);
  60 #endif
  61       if (SCM_MACRO_TYPE (macro) == 2)
  62         scm_puts ("macro!", port);
  63       if (SCM_MACRO_TYPE (macro) == 3)
  64         scm_puts ("builtin-macro!", port);
  65
  66       scm_putc (' ', port);
  67       scm_iprin1 (scm_macro_name (macro), port, pstate);
  68
  69       if (SCM_CLOSUREP (code) && SCM_PRINT_SOURCE_P)
  70         {
  71           SCM formals = SCM_CLOSURE_FORMALS (code);
  72           SCM env = SCM_ENV (code);
  73           SCM xenv = SCM_EXTEND_ENV (formals, SCM_EOL, env);
  74           SCM src = scm_i_unmemocopy_body (SCM_CODE (code), xenv);
  75           scm_putc (' ', port);
  76           scm_iprin1 (src, port, pstate);
  77         }
  78
  79       scm_putc ('>', port);
  80     }
  81
  82   return 1;
  83 }
  84
  85 static SCM
  86 makmac (SCM code, scm_t_bits flags)
  87 {
  88   SCM z;
  89   SCM_NEWSMOB (z, scm_tc16_macro, SCM_UNPACK (code));
  90   SCM_SET_SMOB_FLAGS (z, flags);
  91   return z;
  92 }
  93
  94 /* Return a mmacro that is known to be one of guile's built in macros. */
  95 SCM
  96 scm_i_makbimacro (SCM code)
  97 #define FUNC_NAME "scm_i_makbimacro"
  98 {
  99   SCM_VALIDATE_PROC (1, code);
 100   return makmac (code, 3);
 101 }
 102 #undef FUNC_NAME
 103
 104
 105 SCM_DEFINE (scm_makmmacro, "procedure->memoizing-macro", 1, 0, 0,
 106            (SCM code),
 107             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 108             "appears as the first symbol in an expression, evaluates the\n"
 109             "result of applying @var{code} to the expression and the\n"
 110             "environment.\n\n"
 111             "@code{procedure->memoizing-macro} is the same as\n"
 112             "@code{procedure->macro}, except that the expression returned by\n"
 113             "@var{code} replaces the original macro expression in the memoized\n"
 114             "form of the containing code.")
 115 #define FUNC_NAME s_scm_makmmacro
 116 {
 117   SCM_VALIDATE_PROC (1, code);
 118   return makmac (code, 2);
 119 }
 120 #undef FUNC_NAME
 121
 122
 123 SCM_DEFINE (scm_makacro, "procedure->syntax", 1, 0, 0,
 124             (SCM code),
 125             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 126             "appears as the first symbol in an expression, returns the\n"
 127             "result of applying @var{code} to the expression and the\n"
 128             "environment.")
 129 #define FUNC_NAME s_scm_makacro
 130 {
 131   SCM_VALIDATE_PROC (1, code);
 132   return makmac (code, 0);
 133 }
 134 #undef FUNC_NAME
 135
 136
 137 #if SCM_ENABLE_DEPRECATED == 1
 138
 139 SCM_DEFINE (scm_makmacro, "procedure->macro", 1, 0, 0,
 140            (SCM code),
 141             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 142             "appears as the first symbol in an expression, evaluates the\n"
 143             "result of applying @var{code} to the expression and the\n"
 144             "environment.  For example:\n"
 145             "\n"
 146             "@lisp\n"
 147             "(define trace\n"
 148             "  (procedure->macro\n"
 149             "   (lambda (x env) `(set! ,(cadr x) (tracef ,(cadr x) ',(cadr x))))))\n\n"
 150             "(trace @i{foo}) @equiv{} (set! @i{foo} (tracef @i{foo} '@i{foo})).\n"
 151             "@end lisp")
 152 #define FUNC_NAME s_scm_makmacro
 153 {
 154   scm_c_issue_deprecation_warning
 155     ("The function procedure->macro is deprecated, and so are"
 156      " non-memoizing macros in general.  Use memoizing macros"
 157      " or r5rs macros instead.");
 158
 159   SCM_VALIDATE_PROC (1, code);
 160   return makmac (code, 1);
 161 }
 162 #undef FUNC_NAME
 163
 164 #endif
 165
 166
 167 SCM_DEFINE (scm_macro_p, "macro?", 1, 0, 0,
 168             (SCM obj),
 169             "Return @code{#t} if @var{obj} is a regular macro, a memoizing macro or a\n"
 170             "syntax transformer.")
 171 #define FUNC_NAME s_scm_macro_p
 172 {
 173   return scm_from_bool (SCM_SMOB_PREDICATE (scm_tc16_macro, obj));
 174 }
 175 #undef FUNC_NAME
 176
 177
 178 SCM_SYMBOL (scm_sym_syntax, "syntax");
 179 #if SCM_ENABLE_DEPRECATED == 1
 180 SCM_SYMBOL (scm_sym_macro, "macro");
 181 #endif
 182 SCM_SYMBOL (scm_sym_mmacro, "macro!");
 183 SCM_SYMBOL (scm_sym_bimacro, "builtin-macro!");
 184
 185 SCM_DEFINE (scm_macro_type, "macro-type", 1, 0, 0,
 186             (SCM m),
 187             "Return one of the symbols @code{syntax}, @code{macro} or\n"
 188             "@code{macro!}, depending on whether @var{m} is a syntax\n"
 189             "transformer, a regular macro, or a memoizing macro,\n"
 190             "respectively.  If @var{m} is not a macro, @code{#f} is\n"
 191             "returned.")
 192 #define FUNC_NAME s_scm_macro_type
 193 {
 194   if (!SCM_SMOB_PREDICATE (scm_tc16_macro, m))
 195     return SCM_BOOL_F;
 196   switch (SCM_MACRO_TYPE (m))
 197     {
 198     case 0: return scm_sym_syntax;
 199 #if SCM_ENABLE_DEPRECATED == 1
 200     case 1: return scm_sym_macro;
 201 #endif
 202     case 2: return scm_sym_mmacro;
 203     case 3: return scm_sym_bimacro;
 204     default: scm_wrong_type_arg (FUNC_NAME, 1, m);
 205     }
 206 }
 207 #undef FUNC_NAME
 208
 209
 210 SCM_DEFINE (scm_macro_name, "macro-name", 1, 0, 0,
 211             (SCM m),
 212             "Return the name of the macro @var{m}.")
 213 #define FUNC_NAME s_scm_macro_name
 214 {
 215   SCM_VALIDATE_SMOB (1, m, macro);
 216   return scm_procedure_name (SCM_PACK (SCM_SMOB_DATA (m)));
 217 }
 218 #undef FUNC_NAME
 219
 220
 221 SCM_DEFINE (scm_macro_transformer, "macro-transformer", 1, 0, 0,
 222             (SCM m),
 223             "Return the transformer of the macro @var{m}.")
 224 #define FUNC_NAME s_scm_macro_transformer
 225 {
 226   SCM_VALIDATE_SMOB (1, m, macro);
 227   return ((SCM_CLOSUREP (SCM_PACK (SCM_SMOB_DATA (m)))) ?
 228           SCM_PACK(SCM_SMOB_DATA (m)) : SCM_BOOL_F);
 229 }
 230 #undef FUNC_NAME
 231
 232 SCM
 233 scm_make_synt (const char *name, SCM (*macroizer) (), SCM (*fcn)() )
 234 {
 235   SCM var = scm_c_define (name, SCM_UNDEFINED);
 236   SCM transformer = scm_c_make_subr (name, scm_tc7_subr_2, fcn);
 237   SCM_VARIABLE_SET (var, macroizer (transformer));
 238   return SCM_UNSPECIFIED;
 239 }
 240
 241 void
 242 scm_init_macros ()
 243 {
 244   scm_tc16_macro = scm_make_smob_type ("macro", 0);
 245   scm_set_smob_mark (scm_tc16_macro, scm_markcdr);
 246   scm_set_smob_print (scm_tc16_macro, macro_print);
 247 #include "libguile/macros.x"
 248 }
 249
 250 /*
 251   Local Variables:
 252   c-file-style: "gnu"
 253   End:
 254 */