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/* Scheme/Guile language support routines for GDB, the GNU debugger.

   Copyright 1995, 1996, 1998, 2000 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 2 of the License, or

   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program; if not, write to the Free Software

   Foundation, Inc., 59 Temple Place - Suite 330,

   Boston, MA 02111-1307, USA.  */

#include "defs.h"

#include "symtab.h"

#include "gdbtypes.h"

#include "expression.h"

#include "parser-defs.h"

#include "language.h"

#include "value.h"

#include "c-lang.h"

#include "scm-lang.h"

#include "scm-tags.h"

#include "gdb_string.h"

#include "gdbcore.h"

extern void _initialize_scheme_language (void);

static value_ptr evaluate_subexp_scm (struct type *, struct expression *,

                                      int *, enum noside);

static value_ptr scm_lookup_name (char *);

static int in_eval_c (void);

static void scm_printstr (struct ui_file * stream, char *string,

                          unsigned int length, int width,

                          int force_ellipses);

extern struct type **CONST_PTR (c_builtin_types[]);

struct type *builtin_type_scm;

void

scm_printchar (int c, struct ui_file *stream)

{

  fprintf_filtered (stream, "#\\%c", c);

}

static void

scm_printstr (struct ui_file *stream, char *string, unsigned int length,

              int width, int force_ellipses)

{

  fprintf_filtered (stream, "\"%s\"", string);

}

int

is_scmvalue_type (struct type *type)

{

  if (TYPE_CODE (type) == TYPE_CODE_INT

      && TYPE_NAME (type) && strcmp (TYPE_NAME (type), "SCM") == 0)

    {

      return 1;

    }

  return 0;

}

/* Get the INDEX'th SCM value, assuming SVALUE is the address

   of the 0'th one.  */

LONGEST

scm_get_field (LONGEST svalue, int index)

{

  char buffer[20];

  read_memory (SCM2PTR (svalue) + index * TYPE_LENGTH (builtin_type_scm),

               buffer, TYPE_LENGTH (builtin_type_scm));

  return extract_signed_integer (buffer, TYPE_LENGTH (builtin_type_scm));

}

/* Unpack a value of type TYPE in buffer VALADDR as an integer

   (if CONTEXT == TYPE_CODE_IN), a pointer (CONTEXT == TYPE_CODE_PTR),

   or Boolean (CONTEXT == TYPE_CODE_BOOL).  */

LONGEST

scm_unpack (struct type *type, char *valaddr, enum type_code context)

{

  if (is_scmvalue_type (type))

    {

      LONGEST svalue = extract_signed_integer (valaddr, TYPE_LENGTH (type));

      if (context == TYPE_CODE_BOOL)

        {

          if (svalue == SCM_BOOL_F)

            return 0;

          else

            return 1;

        }

      switch (7 & (int) svalue)

        {

        case 2:

        case 6:         /* fixnum */

          return svalue >> 2;

        case 4:         /* other immediate value */

          if (SCM_ICHRP (svalue))       /* character */

            return SCM_ICHR (svalue);

          else if (SCM_IFLAGP (svalue))

            {

              switch ((int) svalue)

                {

#ifndef SICP

                case SCM_EOL:

#endif

                case SCM_BOOL_F:

                  return 0;

                case SCM_BOOL_T:

                  return 1;

                }

            }

          error ("Value can't be converted to integer.");

        default:

          return svalue;

        }

    }

  else

    return unpack_long (type, valaddr);

}

/* True if we're correctly in Guile's eval.c (the evaluator and apply). */

static int

in_eval_c (void)

{

  if (current_source_symtab && current_source_symtab->filename)

    {

      char *filename = current_source_symtab->filename;

      int len = strlen (filename);

      if (len >= 6 && strcmp (filename + len - 6, "eval.c") == 0)

        return 1;

    }

  return 0;

}

/* Lookup a value for the variable named STR.

   First lookup in Scheme context (using the scm_lookup_cstr inferior

   function), then try lookup_symbol for compiled variables. */

static value_ptr

scm_lookup_name (char *str)

{

  value_ptr args[3];

  int len = strlen (str);

  value_ptr func, val;

  struct symbol *sym;

  args[0] = value_allocate_space_in_inferior (len);

  args[1] = value_from_longest (builtin_type_int, len);

  write_memory (value_as_long (args[0]), str, len);

  if (in_eval_c ()

      && (sym = lookup_symbol ("env",

                               expression_context_block,

                               VAR_NAMESPACE, (int *) NULL,

                               (struct symtab **) NULL)) != NULL)

    args[2] = value_of_variable (sym, expression_context_block);

  else

    /* FIXME in this case, we should try lookup_symbol first */

    args[2] = value_from_longest (builtin_type_scm, SCM_EOL);

  func = find_function_in_inferior ("scm_lookup_cstr");

  val = call_function_by_hand (func, 3, args);

  if (!value_logical_not (val))

    return value_ind (val);

  sym = lookup_symbol (str,

                       expression_context_block,

                       VAR_NAMESPACE, (int *) NULL,

                       (struct symtab **) NULL);

  if (sym)

    return value_of_variable (sym, NULL);

  error ("No symbol \"%s\" in current context.");

}

value_ptr

scm_evaluate_string (char *str, int len)

{

  value_ptr func;

  value_ptr addr = value_allocate_space_in_inferior (len + 1);

  LONGEST iaddr = value_as_long (addr);

  write_memory (iaddr, str, len);

  /* FIXME - should find and pass env */

  write_memory (iaddr + len, "", 1);

  func = find_function_in_inferior ("scm_evstr");

  return call_function_by_hand (func, 1, &addr);

}

static value_ptr

evaluate_subexp_scm (struct type *expect_type, register struct expression *exp,

                     register int *pos, enum noside noside)

{

  enum exp_opcode op = exp->elts[*pos].opcode;

  int len, pc;

  char *str;

  switch (op)

    {

    case OP_NAME:

      pc = (*pos)++;

      len = longest_to_int (exp->elts[pc + 1].longconst);

      (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);

      if (noside == EVAL_SKIP)

        goto nosideret;

      str = &exp->elts[pc + 2].string;

      return scm_lookup_name (str);

    case OP_EXPRSTRING:

      pc = (*pos)++;

      len = longest_to_int (exp->elts[pc + 1].longconst);

      (*pos) += 3 + BYTES_TO_EXP_ELEM (len + 1);

      if (noside == EVAL_SKIP)

        goto nosideret;

      str = &exp->elts[pc + 2].string;

      return scm_evaluate_string (str, len);

    default:;

    }

  return evaluate_subexp_standard (expect_type, exp, pos, noside);

nosideret:

  return value_from_longest (builtin_type_long, (LONGEST) 1);

}

const struct language_defn scm_language_defn =

{

  "scheme",                     /* Language name */

  language_scm,

  c_builtin_types,

  range_check_off,

  type_check_off,

  case_sensitive_off,

  scm_parse,

  c_error,

  evaluate_subexp_scm,

  scm_printchar,                /* Print a character constant */

  scm_printstr,                 /* Function to print string constant */

  NULL,                         /* Function to print a single character */

  NULL,                         /* Create fundamental type in this language */

  c_print_type,                 /* Print a type using appropriate syntax */

  scm_val_print,                /* Print a value using appropriate syntax */

  scm_value_print,              /* Print a top-level value */

  {"", "", "", ""},             /* Binary format info */

  {"#o%lo", "#o", "o", ""},     /* Octal format info */

  {"%ld", "", "d", ""},         /* Decimal format info */

  {"#x%lX", "#X", "X", ""},     /* Hex format info */

  NULL,                         /* expression operators for printing */

  1,                            /* c-style arrays */

  0,                             /* String lower bound */

  &builtin_type_char,           /* Type of string elements */

  LANG_MAGIC

};

void

_initialize_scheme_language (void)

{

  add_language (&scm_language_defn);

  builtin_type_scm = init_type (TYPE_CODE_INT,

                                TARGET_LONG_BIT / TARGET_CHAR_BIT,

                                0, "SCM", (struct objfile *) NULL);

}