libguile/macros.c

   1 /* Copyright (C) 1995,1996,1997,1998,2000,2001,2002,2003 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  16  */
  17
  18
  19 \f
  20
  21 #include "libguile/_scm.h"
  22 #include "libguile/alist.h" /* for SCM_EXTEND_ENV (well...) */
  23 #include "libguile/eval.h"
  24 #include "libguile/ports.h"
  25 #include "libguile/print.h"
  26 #include "libguile/root.h"
  27 #include "libguile/smob.h"
  28 #include "libguile/deprecation.h"
  29
  30 #include "libguile/validate.h"
  31 #include "libguile/macros.h"
  32
  33 scm_t_bits scm_tc16_macro;
  34
  35
  36 static int
  37 macro_print (SCM macro, SCM port, scm_print_state *pstate)
  38 {
  39   SCM code = SCM_MACRO_CODE (macro);
  40   if (!SCM_CLOSUREP (code)
  41       || SCM_FALSEP (scm_procedure_p (SCM_PRINT_CLOSURE))
  42       || SCM_FALSEP (scm_printer_apply (SCM_PRINT_CLOSURE,
  43                                         macro, port, pstate)))
  44     {
  45       if (!SCM_CLOSUREP (code))
  46         scm_puts ("#<primitive-", port);
  47       else
  48         scm_puts ("#<", port);
  49
  50       if (SCM_MACRO_TYPE (macro) == 0)
  51         scm_puts ("syntax", port);
  52 #if SCM_ENABLE_DEPRECATED == 1
  53       if (SCM_MACRO_TYPE (macro) == 1)
  54         scm_puts ("macro", port);
  55 #endif
  56       if (SCM_MACRO_TYPE (macro) == 2)
  57         scm_puts ("macro!", port);
  58       if (SCM_MACRO_TYPE (macro) == 3)
  59         scm_puts ("builtin-macro!", port);
  60
  61       scm_putc (' ', port);
  62       scm_iprin1 (scm_macro_name (macro), port, pstate);
  63
  64       if (SCM_CLOSUREP (code) && SCM_PRINT_SOURCE_P)
  65         {
  66           SCM formals = SCM_CLOSURE_FORMALS (code);
  67           SCM env = SCM_ENV (code);
  68           SCM xenv = SCM_EXTEND_ENV (formals, SCM_EOL, env);
  69           SCM src = scm_unmemocopy (SCM_CODE (code), xenv);
  70           scm_putc (' ', port);
  71           scm_iprin1 (src, port, pstate);
  72         }
  73
  74       scm_putc ('>', port);
  75     }
  76
  77   return 1;
  78 }
  79
  80 static SCM
  81 makmac (SCM code, scm_t_bits flags)
  82 {
  83   SCM z;
  84   SCM_NEWSMOB (z, scm_tc16_macro, SCM_UNPACK (code));
  85   SCM_SET_SMOB_FLAGS (z, flags);
  86   return z;
  87 }
  88
  89 /* Return a mmacro that is known to be one of guile's built in macros. */
  90 SCM
  91 scm_i_makbimacro (SCM code)
  92 #define FUNC_NAME "scm_i_makbimacro"
  93 {
  94   SCM_VALIDATE_PROC (1, code);
  95   return makmac (code, 3);
  96 }
  97 #undef FUNC_NAME
  98
  99
 100 SCM_DEFINE (scm_makmmacro, "procedure->memoizing-macro", 1, 0, 0,
 101            (SCM code),
 102             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 103             "appears as the first symbol in an expression, evaluates the\n"
 104             "result of applying @var{code} to the expression and the\n"
 105             "environment.\n\n"
 106             "@code{procedure->memoizing-macro} is the same as\n"
 107             "@code{procedure->macro}, except that the expression returned by\n"
 108             "@var{code} replaces the original macro expression in the memoized\n"
 109             "form of the containing code.")
 110 #define FUNC_NAME s_scm_makmmacro
 111 {
 112   SCM_VALIDATE_PROC (1, code);
 113   return makmac (code, 2);
 114 }
 115 #undef FUNC_NAME
 116
 117
 118 SCM_DEFINE (scm_makacro, "procedure->syntax", 1, 0, 0,
 119             (SCM code),
 120             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 121             "appears as the first symbol in an expression, returns the\n"
 122             "result of applying @var{code} to the expression and the\n"
 123             "environment.")
 124 #define FUNC_NAME s_scm_makacro
 125 {
 126   SCM_VALIDATE_PROC (1, code);
 127   return makmac (code, 0);
 128 }
 129 #undef FUNC_NAME
 130
 131
 132 #if SCM_ENABLE_DEPRECATED == 1
 133
 134 SCM_DEFINE (scm_makmacro, "procedure->macro", 1, 0, 0,
 135            (SCM code),
 136             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 137             "appears as the first symbol in an expression, evaluates the\n"
 138             "result of applying @var{code} to the expression and the\n"
 139             "environment.  For example:\n"
 140             "\n"
 141             "@lisp\n"
 142             "(define trace\n"
 143             "  (procedure->macro\n"
 144             "   (lambda (x env) `(set! ,(cadr x) (tracef ,(cadr x) ',(cadr x))))))\n\n"
 145             "(trace @i{foo}) @equiv{} (set! @i{foo} (tracef @i{foo} '@i{foo})).\n"
 146             "@end lisp")
 147 #define FUNC_NAME s_scm_makmacro
 148 {
 149   scm_c_issue_deprecation_warning
 150     ("The function procedure->macro is deprecated, and so are"
 151      " non-memoizing macros in general.  Use memoizing macros"
 152      " or r5rs macros instead.");
 153
 154   SCM_VALIDATE_PROC (1, code);
 155   return makmac (code, 1);
 156 }
 157 #undef FUNC_NAME
 158
 159 #endif
 160
 161
 162 SCM_DEFINE (scm_macro_p, "macro?", 1, 0, 0,
 163             (SCM obj),
 164             "Return @code{#t} if @var{obj} is a regular macro, a memoizing macro or a\n"
 165             "syntax transformer.")
 166 #define FUNC_NAME s_scm_macro_p
 167 {
 168   return SCM_BOOL (SCM_SMOB_PREDICATE (scm_tc16_macro, obj));
 169 }
 170 #undef FUNC_NAME
 171
 172
 173 SCM_SYMBOL (scm_sym_syntax, "syntax");
 174 #if SCM_ENABLE_DEPRECATED == 1
 175 SCM_SYMBOL (scm_sym_macro, "macro");
 176 #endif
 177 SCM_SYMBOL (scm_sym_mmacro, "macro!");
 178 SCM_SYMBOL (scm_sym_bimacro, "builtin-macro!");
 179
 180 SCM_DEFINE (scm_macro_type, "macro-type", 1, 0, 0,
 181             (SCM m),
 182             "Return one of the symbols @code{syntax}, @code{macro} or\n"
 183             "@code{macro!}, depending on whether @var{m} is a syntax\n"
 184             "transformer, a regular macro, or a memoizing macro,\n"
 185             "respectively.  If @var{m} is not a macro, @code{#f} is\n"
 186             "returned.")
 187 #define FUNC_NAME s_scm_macro_type
 188 {
 189   if (!SCM_SMOB_PREDICATE (scm_tc16_macro, m))
 190     return SCM_BOOL_F;
 191   switch (SCM_MACRO_TYPE (m))
 192     {
 193     case 0: return scm_sym_syntax;
 194 #if SCM_ENABLE_DEPRECATED == 1
 195     case 1: return scm_sym_macro;
 196 #endif
 197     case 2: return scm_sym_mmacro;
 198     case 3: return scm_sym_bimacro;
 199     default: scm_wrong_type_arg (FUNC_NAME, 1, m);
 200     }
 201 }
 202 #undef FUNC_NAME
 203
 204
 205 SCM_DEFINE (scm_macro_name, "macro-name", 1, 0, 0,
 206             (SCM m),
 207             "Return the name of the macro @var{m}.")
 208 #define FUNC_NAME s_scm_macro_name
 209 {
 210   SCM_VALIDATE_SMOB (1, m, macro);
 211   return scm_procedure_name (SCM_PACK (SCM_SMOB_DATA (m)));
 212 }
 213 #undef FUNC_NAME
 214
 215
 216 SCM_DEFINE (scm_macro_transformer, "macro-transformer", 1, 0, 0,
 217             (SCM m),
 218             "Return the transformer of the macro @var{m}.")
 219 #define FUNC_NAME s_scm_macro_transformer
 220 {
 221   SCM_VALIDATE_SMOB (1, m, macro);
 222   return ((SCM_CLOSUREP (SCM_PACK (SCM_SMOB_DATA (m)))) ?
 223           SCM_PACK(SCM_SMOB_DATA (m)) : SCM_BOOL_F);
 224 }
 225 #undef FUNC_NAME
 226
 227 SCM
 228 scm_make_synt (const char *name, SCM (*macroizer) (), SCM (*fcn)() )
 229 {
 230   SCM var = scm_c_define (name, SCM_UNDEFINED);
 231   SCM transformer = scm_c_make_subr (name, scm_tc7_subr_2, fcn);
 232   SCM_VARIABLE_SET (var, macroizer (transformer));
 233   return SCM_UNSPECIFIED;
 234 }
 235
 236 void
 237 scm_init_macros ()
 238 {
 239   scm_tc16_macro = scm_make_smob_type ("macro", 0);
 240   scm_set_smob_mark (scm_tc16_macro, scm_markcdr);
 241   scm_set_smob_print (scm_tc16_macro, macro_print);
 242 #include "libguile/macros.x"
 243 }
 244
 245 /*
 246   Local Variables:
 247   c-file-style: "gnu"
 248   End:
 249 */