libguile/macros.c

   1 /* Copyright (C) 1995,1996,1997,1998,2000,2001,2002,2003, 2006 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
  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 #include "libguile/private-options.h"
  34
  35 scm_t_bits scm_tc16_macro;
  36
  37
  38 static int
  39 macro_print (SCM macro, SCM port, scm_print_state *pstate)
  40 {
  41   SCM code = SCM_MACRO_CODE (macro);
  42   if (!SCM_CLOSUREP (code)
  43       || scm_is_false (scm_procedure_p (SCM_PRINT_CLOSURE))
  44       || scm_is_false (scm_printer_apply (SCM_PRINT_CLOSURE,
  45                                         macro, port, pstate)))
  46     {
  47       if (!SCM_CLOSUREP (code))
  48         scm_puts ("#<primitive-", port);
  49       else
  50         scm_puts ("#<", port);
  51
  52       if (SCM_MACRO_TYPE (macro) == 0)
  53         scm_puts ("syntax", port);
  54 #if SCM_ENABLE_DEPRECATED == 1
  55       if (SCM_MACRO_TYPE (macro) == 1)
  56         scm_puts ("macro", port);
  57 #endif
  58       if (SCM_MACRO_TYPE (macro) == 2)
  59         scm_puts ("macro!", port);
  60       if (SCM_MACRO_TYPE (macro) == 3)
  61         scm_puts ("builtin-macro!", port);
  62
  63       scm_putc (' ', port);
  64       scm_iprin1 (scm_macro_name (macro), port, pstate);
  65
  66       if (SCM_CLOSUREP (code) && SCM_PRINT_SOURCE_P)
  67         {
  68           SCM formals = SCM_CLOSURE_FORMALS (code);
  69           SCM env = SCM_ENV (code);
  70           SCM xenv = SCM_EXTEND_ENV (formals, SCM_EOL, env);
  71           SCM src = scm_i_unmemocopy_body (SCM_CODE (code), xenv);
  72           scm_putc (' ', port);
  73           scm_iprin1 (src, port, pstate);
  74         }
  75
  76       scm_putc ('>', port);
  77     }
  78
  79   return 1;
  80 }
  81
  82 static SCM
  83 makmac (SCM code, scm_t_bits flags)
  84 {
  85   SCM z;
  86   SCM_NEWSMOB (z, scm_tc16_macro, SCM_UNPACK (code));
  87   SCM_SET_SMOB_FLAGS (z, flags);
  88   return z;
  89 }
  90
  91 /* Return a mmacro that is known to be one of guile's built in macros. */
  92 SCM
  93 scm_i_makbimacro (SCM code)
  94 #define FUNC_NAME "scm_i_makbimacro"
  95 {
  96   SCM_VALIDATE_PROC (1, code);
  97   return makmac (code, 3);
  98 }
  99 #undef FUNC_NAME
 100
 101
 102 SCM_DEFINE (scm_makmmacro, "procedure->memoizing-macro", 1, 0, 0,
 103            (SCM code),
 104             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 105             "appears as the first symbol in an expression, evaluates the\n"
 106             "result of applying @var{code} to the expression and the\n"
 107             "environment.\n\n"
 108             "@code{procedure->memoizing-macro} is the same as\n"
 109             "@code{procedure->macro}, except that the expression returned by\n"
 110             "@var{code} replaces the original macro expression in the memoized\n"
 111             "form of the containing code.")
 112 #define FUNC_NAME s_scm_makmmacro
 113 {
 114   SCM_VALIDATE_PROC (1, code);
 115   return makmac (code, 2);
 116 }
 117 #undef FUNC_NAME
 118
 119
 120 SCM_DEFINE (scm_makacro, "procedure->syntax", 1, 0, 0,
 121             (SCM code),
 122             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 123             "appears as the first symbol in an expression, returns the\n"
 124             "result of applying @var{code} to the expression and the\n"
 125             "environment.")
 126 #define FUNC_NAME s_scm_makacro
 127 {
 128   SCM_VALIDATE_PROC (1, code);
 129   return makmac (code, 0);
 130 }
 131 #undef FUNC_NAME
 132
 133
 134 #if SCM_ENABLE_DEPRECATED == 1
 135
 136 SCM_DEFINE (scm_makmacro, "procedure->macro", 1, 0, 0,
 137            (SCM code),
 138             "Return a @dfn{macro} which, when a symbol defined to this value\n"
 139             "appears as the first symbol in an expression, evaluates the\n"
 140             "result of applying @var{code} to the expression and the\n"
 141             "environment.  For example:\n"
 142             "\n"
 143             "@lisp\n"
 144             "(define trace\n"
 145             "  (procedure->macro\n"
 146             "   (lambda (x env) `(set! ,(cadr x) (tracef ,(cadr x) ',(cadr x))))))\n\n"
 147             "(trace @i{foo}) @equiv{} (set! @i{foo} (tracef @i{foo} '@i{foo})).\n"
 148             "@end lisp")
 149 #define FUNC_NAME s_scm_makmacro
 150 {
 151   scm_c_issue_deprecation_warning
 152     ("The function procedure->macro is deprecated, and so are"
 153      " non-memoizing macros in general.  Use memoizing macros"
 154      " or r5rs macros instead.");
 155
 156   SCM_VALIDATE_PROC (1, code);
 157   return makmac (code, 1);
 158 }
 159 #undef FUNC_NAME
 160
 161 #endif
 162
 163
 164 SCM_DEFINE (scm_macro_p, "macro?", 1, 0, 0,
 165             (SCM obj),
 166             "Return @code{#t} if @var{obj} is a regular macro, a memoizing macro or a\n"
 167             "syntax transformer.")
 168 #define FUNC_NAME s_scm_macro_p
 169 {
 170   return scm_from_bool (SCM_SMOB_PREDICATE (scm_tc16_macro, obj));
 171 }
 172 #undef FUNC_NAME
 173
 174
 175 SCM_SYMBOL (scm_sym_syntax, "syntax");
 176 #if SCM_ENABLE_DEPRECATED == 1
 177 SCM_SYMBOL (scm_sym_macro, "macro");
 178 #endif
 179 SCM_SYMBOL (scm_sym_mmacro, "macro!");
 180 SCM_SYMBOL (scm_sym_bimacro, "builtin-macro!");
 181
 182 SCM_DEFINE (scm_macro_type, "macro-type", 1, 0, 0,
 183             (SCM m),
 184             "Return one of the symbols @code{syntax}, @code{macro} or\n"
 185             "@code{macro!}, depending on whether @var{m} is a syntax\n"
 186             "transformer, a regular macro, or a memoizing macro,\n"
 187             "respectively.  If @var{m} is not a macro, @code{#f} is\n"
 188             "returned.")
 189 #define FUNC_NAME s_scm_macro_type
 190 {
 191   if (!SCM_SMOB_PREDICATE (scm_tc16_macro, m))
 192     return SCM_BOOL_F;
 193   switch (SCM_MACRO_TYPE (m))
 194     {
 195     case 0: return scm_sym_syntax;
 196 #if SCM_ENABLE_DEPRECATED == 1
 197     case 1: return scm_sym_macro;
 198 #endif
 199     case 2: return scm_sym_mmacro;
 200     case 3: return scm_sym_bimacro;
 201     default: scm_wrong_type_arg (FUNC_NAME, 1, m);
 202     }
 203 }
 204 #undef FUNC_NAME
 205
 206
 207 SCM_DEFINE (scm_macro_name, "macro-name", 1, 0, 0,
 208             (SCM m),
 209             "Return the name of the macro @var{m}.")
 210 #define FUNC_NAME s_scm_macro_name
 211 {
 212   SCM_VALIDATE_SMOB (1, m, macro);
 213   return scm_procedure_name (SCM_PACK (SCM_SMOB_DATA (m)));
 214 }
 215 #undef FUNC_NAME
 216
 217
 218 SCM_DEFINE (scm_macro_transformer, "macro-transformer", 1, 0, 0,
 219             (SCM m),
 220             "Return the transformer of the macro @var{m}.")
 221 #define FUNC_NAME s_scm_macro_transformer
 222 {
 223   SCM_VALIDATE_SMOB (1, m, macro);
 224   return ((SCM_CLOSUREP (SCM_PACK (SCM_SMOB_DATA (m)))) ?
 225           SCM_PACK(SCM_SMOB_DATA (m)) : SCM_BOOL_F);
 226 }
 227 #undef FUNC_NAME
 228
 229 SCM
 230 scm_make_synt (const char *name, SCM (*macroizer) (), SCM (*fcn)() )
 231 {
 232   SCM var = scm_c_define (name, SCM_UNDEFINED);
 233   SCM transformer = scm_c_make_subr (name, scm_tc7_subr_2, fcn);
 234   SCM_VARIABLE_SET (var, macroizer (transformer));
 235   return SCM_UNSPECIFIED;
 236 }
 237
 238 void
 239 scm_init_macros ()
 240 {
 241   scm_tc16_macro = scm_make_smob_type ("macro", 0);
 242   scm_set_smob_print (scm_tc16_macro, macro_print);
 243 #include "libguile/macros.x"
 244 }
 245
 246 /*
 247   Local Variables:
 248   c-file-style: "gnu"
 249   End:
 250 */