libguile/macros.c

   1 /* Copyright (C) 1995,1996,1997,1998,2000,2001,2002 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       scm_putc (' ', port);
  59       scm_iprin1 (scm_macro_name (macro), port, pstate);
  60
  61       if (SCM_CLOSUREP (code) && SCM_PRINT_SOURCE_P)
  62         {
  63           SCM formals = SCM_CLOSURE_FORMALS (code);
  64           SCM env = SCM_ENV (code);
  65           SCM xenv = SCM_EXTEND_ENV (formals, SCM_EOL, env);
  66           SCM src = scm_unmemocopy (SCM_CODE (code), xenv);
  67           scm_putc (' ', port);
  68           scm_iprin1 (src, port, pstate);
  69         }
  70
  71       scm_putc ('>', port);
  72     }
  73
  74   return 1;
  75 }
  76
  77
  78 SCM_DEFINE (scm_makacro, "procedure->syntax", 1, 0, 0,
  79             (SCM code),
  80             "Return a @dfn{macro} which, when a symbol defined to this value\n"
  81             "appears as the first symbol in an expression, returns the\n"
  82             "result of applying @var{code} to the expression and the\n"
  83             "environment.")
  84 #define FUNC_NAME s_scm_makacro
  85 {
  86   SCM_VALIDATE_PROC (1, code);
  87   SCM_RETURN_NEWSMOB (scm_tc16_macro, SCM_UNPACK (code));
  88 }
  89 #undef FUNC_NAME
  90
  91
  92 #if SCM_ENABLE_DEPRECATED == 1
  93
  94 SCM_DEFINE (scm_makmacro, "procedure->macro", 1, 0, 0,
  95            (SCM code),
  96             "Return a @dfn{macro} which, when a symbol defined to this value\n"
  97             "appears as the first symbol in an expression, evaluates the\n"
  98             "result of applying @var{code} to the expression and the\n"
  99             "environment.  For example:\n"
 100             "\n"
 101             "@lisp\n"
 102             "(define trace\n"
 103             "  (procedure->macro\n"
 104             "   (lambda (x env) `(set! ,(cadr x) (tracef ,(cadr x) ',(cadr x))))))\n\n"
 105             "(trace @i{foo}) @equiv{} (set! @i{foo} (tracef @i{foo} '@i{foo})).\n"
 106             "@end lisp")
 107 #define FUNC_NAME s_scm_makmacro
 108 {
 109   scm_c_issue_deprecation_warning
 110     ("The function procedure->macro is deprecated, and so are"
 111      " non-memoizing macros in general.  Use memoizing macros"
 112      " or r5rs macros instead.");
 113
 114   SCM_VALIDATE_PROC (1, code);
 115   SCM_RETURN_NEWSMOB (scm_tc16_macro | (1L << 16), SCM_UNPACK (code));
 116 }
 117 #undef FUNC_NAME
 118
 119 #endif
 120
 121
 122 SCM_DEFINE (scm_makmmacro, "procedure->memoizing-macro", 1, 0, 0,
 123            (SCM code),
 124             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 125             "appears as the first symbol in an expression, evaluates the\n"
 126             "result of applying @var{code} to the expression and the\n"
 127             "environment.\n\n"
 128             "@code{procedure->memoizing-macro} is the same as\n"
 129             "@code{procedure->macro}, except that the expression returned by\n"
 130             "@var{code} replaces the original macro expression in the memoized\n"
 131             "form of the containing code.")
 132 #define FUNC_NAME s_scm_makmmacro
 133 {
 134   SCM_VALIDATE_PROC (1, code);
 135   SCM_RETURN_NEWSMOB (scm_tc16_macro | (2L << 16), SCM_UNPACK (code));
 136 }
 137 #undef FUNC_NAME
 138
 139
 140 SCM_DEFINE (scm_macro_p, "macro?", 1, 0, 0,
 141             (SCM obj),
 142             "Return @code{#t} if @var{obj} is a regular macro, a memoizing macro or a\n"
 143             "syntax transformer.")
 144 #define FUNC_NAME s_scm_macro_p
 145 {
 146   return SCM_BOOL (SCM_TYP16_PREDICATE (scm_tc16_macro, obj));
 147 }
 148 #undef FUNC_NAME
 149
 150
 151 SCM_SYMBOL (scm_sym_syntax, "syntax");
 152 #if SCM_ENABLE_DEPRECATED == 1
 153 SCM_SYMBOL (scm_sym_macro, "macro");
 154 #endif
 155 SCM_SYMBOL (scm_sym_mmacro, "macro!");
 156
 157 SCM_DEFINE (scm_macro_type, "macro-type", 1, 0, 0,
 158             (SCM m),
 159             "Return one of the symbols @code{syntax}, @code{macro} or\n"
 160             "@code{macro!}, depending on whether @var{m} is a syntax\n"
 161             "transformer, a regular macro, or a memoizing macro,\n"
 162             "respectively.  If @var{m} is not a macro, @code{#f} is\n"
 163             "returned.")
 164 #define FUNC_NAME s_scm_macro_type
 165 {
 166   if (!SCM_TYP16_PREDICATE (scm_tc16_macro, m))
 167     return SCM_BOOL_F;
 168   switch (SCM_MACRO_TYPE (m))
 169     {
 170     case 0: return scm_sym_syntax;
 171 #if SCM_ENABLE_DEPRECATED == 1
 172     case 1: return scm_sym_macro;
 173 #endif
 174     case 2: return scm_sym_mmacro;
 175     default: scm_wrong_type_arg (FUNC_NAME, 1, m);
 176     }
 177 }
 178 #undef FUNC_NAME
 179
 180
 181 SCM_DEFINE (scm_macro_name, "macro-name", 1, 0, 0,
 182             (SCM m),
 183             "Return the name of the macro @var{m}.")
 184 #define FUNC_NAME s_scm_macro_name
 185 {
 186   SCM_VALIDATE_SMOB (1, m, macro);
 187   return scm_procedure_name (SCM_PACK (SCM_SMOB_DATA (m)));
 188 }
 189 #undef FUNC_NAME
 190
 191
 192 SCM_DEFINE (scm_macro_transformer, "macro-transformer", 1, 0, 0,
 193             (SCM m),
 194             "Return the transformer of the macro @var{m}.")
 195 #define FUNC_NAME s_scm_macro_transformer
 196 {
 197   SCM_VALIDATE_SMOB (1, m, macro);
 198   return ((SCM_CLOSUREP (SCM_PACK (SCM_SMOB_DATA (m)))) ?
 199           SCM_PACK(SCM_SMOB_DATA (m)) : SCM_BOOL_F);
 200 }
 201 #undef FUNC_NAME
 202
 203 SCM
 204 scm_make_synt (const char *name, SCM (*macroizer) (), SCM (*fcn)() )
 205 {
 206   SCM var = scm_c_define (name, SCM_UNDEFINED);
 207   SCM transformer = scm_c_make_subr (name, scm_tc7_subr_2, fcn);
 208   SCM_VARIABLE_SET (var, macroizer (transformer));
 209   return SCM_UNSPECIFIED;
 210 }
 211
 212 void
 213 scm_init_macros ()
 214 {
 215   scm_tc16_macro = scm_make_smob_type ("macro", 0);
 216   scm_set_smob_mark (scm_tc16_macro, scm_markcdr);
 217   scm_set_smob_print (scm_tc16_macro, macro_print);
 218 #include "libguile/macros.x"
 219 }
 220
 221 /*
 222   Local Variables:
 223   c-file-style: "gnu"
 224   End:
 225 */