guile/libguile/syntax.c

/* Copyright 2017-2018,2021,2025
     Free Software Foundation, Inc.

   This file is part of Guile.

   Guile is free software: you can redistribute it and/or modify it
   under the terms of the GNU Lesser General Public License as published
   by the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   Guile is distributed in the hope that it will be useful, but WITHOUT
   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
   License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with Guile.  If not, see
   <https://www.gnu.org/licenses/>.  */




#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include "alist.h"
#include "eval.h"
#include "gsubr.h"
#include "keywords.h"
#include "modules.h"
#include "pairs.h"
#include "ports.h"
#include "threads.h"
#include "variable.h"
#include "vectors.h"

#include "syntax.h"




struct scm_syntax
{
  scm_t_bits tag;
  SCM expr;
  SCM wrap;
  SCM module;
  SCM source;
};

static int
scm_is_syntax (SCM x)
{
  return SCM_HAS_TYP7 (x, scm_tc7_syntax);
}

static inline struct scm_syntax *
scm_to_syntax (SCM x)
{
  if (!scm_is_syntax (x))
    abort ();
  return (struct scm_syntax *) SCM_UNPACK_POINTER (x);
}

static inline SCM
scm_from_syntax (struct scm_syntax *stx)
{
  return SCM_PACK_POINTER (stx);
}

#define SCM_VALIDATE_SYNTAX(pos, scm) \
  SCM_I_MAKE_VALIDATE_MSG2 (pos, scm, scm_is_syntax, "syntax object")

SCM_DEFINE (scm_syntax_p, "syntax?", 1, 0, 0,
            (SCM obj),
	    "Return @code{#t} if the argument @var{obj} is a syntax object,\n"
            "else @code{#f}.")
#define FUNC_NAME s_scm_syntax_p
{
  return scm_from_bool (scm_is_syntax (obj));
}
#undef FUNC_NAME

SCM_DEFINE (scm_make_syntax, "make-syntax", 3, 1, 0,
	    (SCM exp, SCM wrap, SCM module, SCM source),
	    "Make a new syntax object.")
#define FUNC_NAME s_scm_make_syntax
{
  if (SCM_UNBNDP (source))
    source = SCM_BOOL_F;
  else if (!scm_is_eq (source, SCM_BOOL_F))
    SCM_VALIDATE_VECTOR (1, source);

  struct scm_syntax *ret = scm_allocate_tagged (SCM_I_CURRENT_THREAD,
                                                sizeof (*ret));
  ret->tag = scm_tc7_syntax;
  ret->expr = exp;
  ret->wrap = wrap;
  ret->module = module;
  ret->source = source;

  return scm_from_syntax (ret);
}
#undef FUNC_NAME

SCM_DEFINE (scm_syntax_expression, "syntax-expression", 1, 0, 0,
	    (SCM obj),
	    "Return the expression contained in the syntax object @var{obj}.")
#define FUNC_NAME s_scm_syntax_expression
{
  SCM_VALIDATE_SYNTAX (1, obj);
  return scm_to_syntax (obj)->expr;
}
#undef FUNC_NAME

SCM_DEFINE (scm_syntax_wrap, "syntax-wrap", 1, 0, 0,
	    (SCM obj),
	    "Return the wrap contained in the syntax object @var{obj}.")
#define FUNC_NAME s_scm_syntax_wrap
{
  SCM_VALIDATE_SYNTAX (1, obj);
  return scm_to_syntax (obj)->wrap;
}
#undef FUNC_NAME

SCM_DEFINE (scm_syntax_module, "syntax-module", 1, 0, 0,
	    (SCM obj),
	    "Return the module info contained in the syntax object @var{obj}.")
#define FUNC_NAME s_scm_syntax_module
{
  SCM_VALIDATE_SYNTAX (1, obj);
  return scm_to_syntax (obj)->module;
}
#undef FUNC_NAME

SCM_DEFINE (scm_syntax_source, "syntax-source", 1, 0, 0,
	    (SCM obj),
	    "Return the source properties for syntax object @var{obj}, as\n"
            "an alist possibly containing the keys @code{filename},\n"
            "@code{line}, and @code{column}.  Return @code{#f} if no\n"
            "source properties are available.")
#define FUNC_NAME s_scm_syntax_source
{
  SCM_VALIDATE_SYNTAX (1, obj);
  return scm_to_syntax (obj)->source;
}
#undef FUNC_NAME

static SCM print_syntax_var;

static void
init_print_syntax_var (void)
{
  print_syntax_var =
    scm_c_private_variable ("system syntax", "print-syntax");
}

void
scm_i_syntax_print (SCM obj, SCM port, scm_print_state *pstate)
{
  static scm_i_pthread_once_t once = SCM_I_PTHREAD_ONCE_INIT;
  scm_i_pthread_once (&once, init_print_syntax_var);
  scm_call_2 (scm_variable_ref (print_syntax_var), obj, port);
}

void
scm_init_syntax ()
{
#include "syntax.x"
}