// Symbol table classes.                              -*- C++ -*-
/*

Copyright (C) 1992, 1993 John W. Eaton

This file is part of Octave.

Octave 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, or (at your option) any
later version.

Octave 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 Octave; see the file COPYING.  If not, write to the Free
Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

*/

// Don't even think about moving the tree.h include to symtab.h...

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "symtab.h"
#include "error.h"
#include "variables.h"
#include "utils.h"
#include "tree.h"
#include "tree-const.h"

/*
 * Variables and functions.
 */
symbol_def::symbol_def (void)
{
  init_state ();
}

symbol_def::symbol_def (tree_constant *t)
{
  init_state ();
  definition = t;
  type = USER_VARIABLE;
}

symbol_def::symbol_def (tree_builtin *t)
{
  init_state ();
  definition = t;
  type = BUILTIN_FUNCTION;
}

symbol_def::symbol_def (tree_function *t)
{
  init_state ();
  definition = t;
  type = USER_FUNCTION;
}

void
symbol_def::init_state (void)
{
  type = UNKNOWN;
  eternal = 0;
  read_only = 0;

  help_string = (char *) NULL;
  definition = NULL_TREE;
  next_elem = (symbol_def *) NULL;
  count = 0;
}

symbol_def::~symbol_def (void)
{
  delete [] help_string;
  delete definition;
}

int
symbol_def::is_variable (void) const
{
  return (type == USER_VARIABLE || type == BUILTIN_VARIABLE);
}

int
symbol_def::is_function (void) const
{
  return (type == USER_FUNCTION || type == BUILTIN_FUNCTION);
}

int
symbol_def::is_user_variable (void) const
{
  return (type == USER_VARIABLE);
}

int
symbol_def::is_user_function (void) const
{
  return (type == USER_FUNCTION);
}

int
symbol_def::is_builtin_variable (void) const
{
  return (type == BUILTIN_VARIABLE);
}

int
symbol_def::is_builtin_function (void) const
{
  return (type == BUILTIN_FUNCTION);
}

void
symbol_def::define (tree_constant *t)
{
  definition = t;
  if (! is_builtin_variable ())
    type = USER_VARIABLE;
}

void
symbol_def::define (tree_builtin *t)
{
  definition = t;
  type = BUILTIN_FUNCTION;
}

void
symbol_def::define (tree_function *t)
{
  definition = t;
  type = USER_FUNCTION;
}

void
symbol_def::protect (void)
{
  read_only = 1;
}

void
symbol_def::unprotect (void)
{
  read_only = 0;

}

void
symbol_def::make_eternal (void)
{
  eternal = 1;
}

tree *
symbol_def::def (void) const
{
  return definition;
}

char *
symbol_def::help (void) const
{
  return help_string;
}

void
symbol_def::document (const char *h)
{
  delete [] help_string;
  help_string = strsave (h);
}

int
symbol_def::save (ostream& os, int mark_as_global)
{
  return definition->save (os, mark_as_global);
}

int
maybe_delete (symbol_def *def)
{
  int count = 0;
  if (def != (symbol_def *) NULL)
    {
      if (def->count > 0)
	{
	  def->count--;
	  count = def->count;
	  if (def->count == 0)
	    delete def;
	}
    }
  return count;
}

/*
 * Individual records in a symbol table.
 */
symbol_record::symbol_record (void)
{
  init_state ();
}

symbol_record::symbol_record (const char *n,
			      symbol_record *nxt = (symbol_record *) NULL)
{
  init_state ();
  nm = strsave (n);
  next_elem = nxt;
}

void
symbol_record::init_state (void)
{
  formal_param = 0;
  linked_to_global = 0;
  nm = (char *) NULL;
  sv_fcn = (sv_Function) NULL;
  definition = (symbol_def *) NULL;
  next_elem = (symbol_record *) NULL;
}

symbol_record::~symbol_record (void)
{
  delete [] nm;
}

char *
symbol_record::name (void) const
{
  return nm;
}

char *
symbol_record::help (void) const
{
  if (definition != (symbol_def *) NULL)
    return definition->help ();
  else
    return (char *) NULL;
}

void
symbol_record::rename (const char *n)
{
  delete [] nm;
  nm = strsave (n);
}

tree *
symbol_record::def (void) const
{
  if (definition != (symbol_def *) NULL)
    return definition->def ();
  else
    return NULL_TREE;
}

int
symbol_record::is_function (void) const
{
  if (definition != (symbol_def *) NULL)
    return definition->is_function ();
  else
    return 0;
}

int
symbol_record::is_user_function (void) const
{
  if (definition != (symbol_def *) NULL)
    return definition->is_user_function ();
  else
    return 0;
}

int
symbol_record::is_builtin_function (void) const
{
  if (definition != (symbol_def *) NULL)
    return definition->is_builtin_function ();
  else
    return 0;
}

int
symbol_record::is_variable (void) const
{
  if (definition != (symbol_def *) NULL)
    return definition->is_variable ();
  else
    return 0;
}

int
symbol_record::is_user_variable (void) const
{
  if (definition != (symbol_def *) NULL)
    return definition->is_user_variable ();
  else
    return 0;
}

int
symbol_record::is_builtin_variable (void) const
{
  if (definition != (symbol_def *) NULL)
    return definition->is_builtin_variable ();
  else
    return 0;
}

unsigned
symbol_record::type (void) const
{
  if (definition != (symbol_def *) NULL)
    return definition->type;
  else
    return 0;
}

int
symbol_record::is_defined (void) const
{
  if (definition != (symbol_def *) NULL)
    return (definition->def () != NULL_TREE);
  else
    return 0;
}

int
symbol_record::is_read_only (void) const
{
  if (definition != (symbol_def *) NULL)
    return definition->read_only;
  else
    return 0;
}

int
symbol_record::is_eternal (void) const
{
  if (definition != (symbol_def *) NULL)
    return definition->eternal;
  else
    return 0;
}

void
symbol_record::protect (void)
{
  if (definition != (symbol_def *) NULL)
    {
      definition->protect ();

      if (! is_defined ())
	warning ("protecting undefined variable `%s'", nm);
    }
}

void
symbol_record::unprotect (void)
{
  if (definition != (symbol_def *) NULL)
    definition->unprotect ();
}

void
symbol_record::make_eternal (void)
{
  if (definition != (symbol_def *) NULL)
    {
      definition->make_eternal ();

      if (! is_defined ())
	warning ("giving eternal life to undefined variable `%s'", nm);
    }
}

void
symbol_record::set_sv_function (sv_Function f)
{
  sv_fcn = f;
}

int
symbol_record::define (tree_constant *t)
{
  if (is_variable () && read_only_error ())
    return 0;

  tree *saved_def = NULL_TREE;
  if (definition == (symbol_def *) NULL)
    {
      definition = new symbol_def ();
      definition->count = 1;
    }
  else if (is_function ())
    {
      symbol_def *new_def = new symbol_def ();
      push_def (new_def);
      definition->count = 1;
    }
  else if (is_variable ())
    {
      saved_def = definition->def ();
    }

  definition->define (t);

  if (sv_fcn != (sv_Function) NULL && sv_fcn () < 0)
    {
// Would be nice to be able to avoid this cast.  XXX FIXME XXX
      definition->define ((tree_constant *) saved_def);
      delete t;
      return 0;
    }

  delete saved_def;

  return 1;
}

int
symbol_record::define (tree_builtin *t)
{
  if (read_only_error ())
    return 0;

  if (is_variable ())
    {
      symbol_def *old_def = pop_def ();
      maybe_delete (old_def);
    }

  if (is_function ())
    {
      symbol_def *old_def = pop_def ();
      maybe_delete (old_def);
    }

  symbol_def *new_def = new symbol_def (t);
  push_def (new_def);
  definition->count = 1;

  return 1;
}

int
symbol_record::define (tree_function *t)
{
  if (read_only_error ())
    return 0;

  if (is_variable ())
    {
      symbol_def *old_def = pop_def ();
      maybe_delete (old_def);
    }

  if (is_function ())
    {
      symbol_def *old_def = pop_def ();
      maybe_delete (old_def);
    }

  symbol_def *new_def = new symbol_def (t);
  push_def (new_def);
  definition->count = 1;

  return 1;
}

int
symbol_record::define_as_fcn (tree_constant *t)
{
  if (is_variable () && read_only_error ())
    return 0;

  if (is_variable ())
    {
      symbol_def *old_def = pop_def ();
      maybe_delete (old_def);
    }

  if (is_function ())
    {
      symbol_def *old_def = pop_def ();
      maybe_delete (old_def);
    }

  symbol_def *new_def = new symbol_def (t);
  push_def (new_def);
  definition->count = 1;
  definition->type = symbol_def::BUILTIN_FUNCTION;

  return 1;
}

int
symbol_record::define_builtin_var (tree_constant *t)
{
  define (t);
  if (is_variable ())
    definition->type = symbol_def::BUILTIN_VARIABLE;
}

void
symbol_record::document (const char *h)
{
  if (definition != (symbol_def *) NULL)
    {
      definition->document (h);

      if (! is_defined ())
	warning ("documenting undefined variable `%s'", nm);
    }
}

int
symbol_record::save (ostream& os, int mark_as_global = 0)
{
  int status = -1;

// This is a kludge, but hey, it doesn't make sense to save them
// anyway, does it?  Even if it did, we would just have trouble trying
// to read NaN and Inf on lots of systems anyway...
//
// Should we also save the help string?  Maybe someday.

  if (is_read_only ())
    warning ("save: sorry, can't save read-only variable `%s'", nm);
  else if (is_function ())
    warning ("save: sorry, can't save function `%s'", nm);
  else if (is_defined ())
    {
      os << "# name: " << nm << "\n";
      status = definition->save (os, mark_as_global);
    }

  return status;
}

int
symbol_record::clear (void)
{
  int count = 0;
  if (linked_to_global)
    {
      count = maybe_delete (definition);
      definition = (symbol_def *) NULL;
      linked_to_global = 0;
    }
  else
    {
      symbol_def *old_def = pop_def ();
      count = maybe_delete (old_def);
    }
  return count;
}

void
symbol_record::alias (symbol_record *s, int force = 0)
{
  sv_fcn = s->sv_fcn;

  if (force && s->definition == (symbol_def *) NULL)
    {
      s->definition = new symbol_def ();
      definition = s->definition;
      definition->count = 2; // Yes, this is correct.
    }
  else if (s->definition != (symbol_def *) NULL)
    {
      definition = s->definition;
      definition->count++;
    }
}

void
symbol_record::mark_as_formal_parameter (void)
{
  formal_param = 1;
}

int
symbol_record::is_formal_parameter (void) const
{
  return formal_param;
}

void
symbol_record::mark_as_linked_to_global (void)
{
  linked_to_global = 1;
}

int
symbol_record::is_linked_to_global (void) const
{
  return linked_to_global;
}

symbol_record *
symbol_record::next (void) const
{
  return next_elem;
}

void
symbol_record::chain (symbol_record *s)
{
  next_elem = s;
}

void
symbol_record::push_context (void)
{
  context.push (definition);
  definition = (symbol_def *) NULL;
}

void
symbol_record::pop_context (void)
{
  assert (! context.empty ());

  if (is_variable ())
    {
      symbol_def *old_def = pop_def ();
      maybe_delete (old_def);
    }

  if (is_function ())
    {
      symbol_def *old_def = pop_def ();
      maybe_delete (old_def);
    }

  definition = context.pop ();
}

int
symbol_record::read_only_error (void)
{
  if (is_read_only ())
    {
      char *tag = "symbol";
      if (is_variable ())
	tag = "variable";
      else if (is_function ())
	tag = "function";
	
      ::error ("can't redefined read-only %s `%s'", tag, nm);

      return 1;
    }
  else
    return 0;
}

void
symbol_record::push_def (symbol_def *sd)
{
  if (sd == (symbol_def *) NULL)
    return;

  sd->next_elem = definition;
  definition = sd;
}

symbol_def *
symbol_record::pop_def (void)
{
  symbol_def *top = definition;
  if (definition != (symbol_def *) NULL)
    definition = definition->next_elem;
  return top;
}

/*
 * A structure for handling verbose information about a symbol_record.
 */

symbol_record_info::symbol_record_info (void)
{
  init_state ();
}

symbol_record_info::symbol_record_info (const symbol_record& sr)
{
  init_state ();

  type = sr.type ();

  if (sr.is_variable () && sr.is_defined ())
    {
// Would be nice to avoid this cast.  XXX FIXME XXX
      tree_constant *tmp = (tree_constant *) sr.def ();
      switch (tmp->const_type ())
	{
	case tree_constant_rep::scalar_constant:
	  const_type = SR_INFO_SCALAR;
	  break;
	case tree_constant_rep::complex_scalar_constant:
	  const_type = SR_INFO_COMPLEX_SCALAR;
	  break;
	case tree_constant_rep::matrix_constant:
	  const_type = SR_INFO_MATRIX;
	  break;
	case tree_constant_rep::complex_matrix_constant:
	  const_type = SR_INFO_COMPLEX_MATRIX;
	  break;
	case tree_constant_rep::range_constant:
	  const_type = SR_INFO_RANGE;
	  break;
	case tree_constant_rep::string_constant:
	  const_type = SR_INFO_STRING;
	  break;
	default:
	  break;
	}

      nr = tmp->rows ();
      nc = tmp->columns ();

      symbol_def *sr_def = sr.definition;
      symbol_def *hidden_def = sr_def->next_elem;
      if (hidden_def != (symbol_def *) NULL)
	{
	  if (hidden_def->is_user_function ())
	    hides = SR_INFO_USER_FUNCTION;
	  else if (hidden_def->is_builtin_function ())
	    hides = SR_INFO_BUILTIN_FUNCTION;
	}
    }

  eternal = sr.is_eternal ();
  read_only = sr.is_read_only ();

  nm = strsave (sr.name ());

  initialized = 1;
}

symbol_record_info::symbol_record_info (const symbol_record_info& s)
{
  type = s.type;
  const_type = s.const_type;
  hides = s.hides;
  eternal = s.eternal;
  read_only = s.read_only;
  nr = s.nr;
  nc = s.nc;
  nm = strsave (s.nm);
  initialized = s.initialized;
}

symbol_record_info::~symbol_record_info (void)
{
  delete nm;
}

symbol_record_info&
symbol_record_info::operator = (const symbol_record_info& s)
{
  if (this != &s)
    {
      delete nm;
      type = s.type;
      const_type = s.const_type;
      hides = s.hides;
      eternal = s.eternal;
      read_only = s.read_only;
      nr = s.nr;
      nc = s.nc;
      nm = strsave (s.nm);
      initialized = s.initialized;
    }
  return *this;
}

int
symbol_record_info::is_defined (void) const
{
  return initialized;
}

int
symbol_record_info::is_read_only (void) const
{
  return read_only;
}

int
symbol_record_info::is_eternal (void) const
{
  return eternal;
}

int
symbol_record_info::hides_fcn (void) const
{
  return (hides & SR_INFO_USER_FUNCTION);
}

int
symbol_record_info::hides_builtin (void) const
{
  return (hides & SR_INFO_BUILTIN_FUNCTION);
}

char *
symbol_record_info::type_as_string (void) const
{
  if (type == symbol_def::USER_FUNCTION)
    return "user function";
  else if (type == symbol_def::BUILTIN_FUNCTION)
    return "builtin function";
  else
    {
      if (const_type == SR_INFO_SCALAR)
	return "real scalar";
      else if (const_type == SR_INFO_COMPLEX_SCALAR)
	return "complex scalar";
      else if (const_type == SR_INFO_MATRIX)
	return "real matrix";
      else if (const_type == SR_INFO_COMPLEX_MATRIX)
	return "complex matrix";
      else if (const_type == SR_INFO_RANGE)
	return "range";
      else if (const_type == SR_INFO_STRING)
	return "string";
      else
	return "";
    }
}

int
symbol_record_info::is_function (void) const
{
  return (type == symbol_def::USER_FUNCTION
	  || type == symbol_def::BUILTIN_FUNCTION);
}

int
symbol_record_info::rows (void) const
{
  return nr;
}

int
symbol_record_info::columns (void) const
{
  return nc;
}

char *
symbol_record_info::name (void) const
{
  return nm;
}

void
symbol_record_info::init_state (void)
{
  initialized = 0;
  type = symbol_def::UNKNOWN;
  const_type = SR_INFO_UNKNOWN;
  hides = SR_INFO_NONE;
  eternal = 0;
  read_only = 0;
  nr = -1;
  nc = -1;
  nm = (char *) NULL;
}

/*
 * A symbol table.
 */

symbol_table::symbol_table (void)
{
}

symbol_record *
symbol_table::lookup (const char *nm, int insert = 0, int warn = 0)
{
  int index = hash (nm) & HASH_MASK;

  symbol_record *ptr = table[index].next ();

  while (ptr != (symbol_record *) NULL)
    {
      if (strcmp (ptr->name (), nm) == 0)
	return ptr;
      ptr = ptr->next ();
    }

  if (insert)
    {
      symbol_record *new_sym;
      new_sym = new symbol_record (nm, table[index].next ());
      table[index].chain (new_sym);
      return new_sym;
    }
  else if (warn)
    warning ("lookup: symbol`%s' not found", nm);

  return (symbol_record *) NULL;
}

void
symbol_table::clear (int clear_user_functions = 1)
{
  for (int i = 0; i < HASH_TABLE_SIZE; i++)
    {
      symbol_record *ptr = table[i].next ();

      while (ptr != (symbol_record *) NULL)
	{
	  if (ptr->is_user_variable ()
	      || (clear_user_functions && ptr->is_user_function ()))
	    {
	      ptr->clear ();
	    }

	  ptr = ptr->next ();
	}
    }
}

int
symbol_table::clear (const char *nm, int clear_user_functions = 1)
{
  int index = hash (nm) & HASH_MASK;

  symbol_record *ptr = table[index].next ();

  while (ptr != (symbol_record *) NULL)
    {
      if (strcmp (ptr->name (), nm) == 0
	  && (ptr->is_user_variable ()
	      || (clear_user_functions && ptr->is_user_function ())))
	{
	  ptr->clear ();
	  return 1;
	}
      ptr = ptr->next ();
    }

  return 0;
}

int
symbol_table::save (ostream& os, int mark_as_global = 0)
{
  int status = 0;
  int count;
  char **names = list (count, 1, symbol_def::USER_VARIABLE);
  char **ptr = names;
  if (ptr != (char **) NULL)
    {
      while (*ptr != (char *) NULL)
	{
	  if (save (os, *ptr, mark_as_global))
	    status++;
	  delete [] *ptr++;
	}
      delete [] names;
    }
  return status;
}

int
symbol_table::save (ostream& os, const char *name, int mark_as_global = 0)
{
  int status = 0;
  symbol_record *sr = lookup (name, 0, 0);
  if (sr != (symbol_record *) NULL)
    status = sr->save (os, mark_as_global);
  return status;
}

int
symbol_table::size (void) const
{
  int count = 0;
  for (int i = 0; i < HASH_TABLE_SIZE; i++)
    {
      symbol_record *ptr = table[i].next ();
      while (ptr != (symbol_record *) NULL)
	{
	  count++;
	  ptr = ptr->next ();
	}
    }
  return count;
}

static inline int
pstrcmp (char **a, char **b)
{
  return strcmp (*a, *b);
}

static inline int
symbol_record_info_cmp (symbol_record_info *a, symbol_record_info *b)
{
  return strcmp (a->name (), b->name ());
}

// This function should probably share code with symbol_table::list.
// XXX FIXME XXX

symbol_record_info *
symbol_table::long_list (int& count, int sort = 0,
			 unsigned type = SYMTAB_ALL_TYPES,
			 unsigned scope = SYMTAB_ALL_SCOPES) const
{
  count = 0;
  int n = size ();
  if (n == 0)
    return (symbol_record_info *) NULL;

  symbol_record_info *symbols = new symbol_record_info [n+1];
  for (int i = 0; i < HASH_TABLE_SIZE; i++)
    {
      symbol_record *ptr = table[i].next ();
      while (ptr != (symbol_record *) NULL)
	{
	  assert (count < n);
	  unsigned my_scope = ptr->is_linked_to_global () + 1; // Tricky...
	  unsigned my_type = ptr->type ();
	  if ((type & my_type) && (scope & my_scope))
	    {
	      symbols[count++] = symbol_record_info (*ptr);
	    }
	  ptr = ptr->next ();
	}
    }
  symbols[count] = symbol_record_info ();

  if (sort && symbols != (symbol_record_info *) NULL)
    qsort ((void *) symbols, count, sizeof (symbol_record_info),
	   (int (*)(void*, void*)) symbol_record_info_cmp);

  return symbols;
}

char **
symbol_table::list (int& count, int sort = 0,
		    unsigned type = SYMTAB_ALL_TYPES,
		    unsigned scope = SYMTAB_ALL_SCOPES) const
{
  count = 0;
  int n = size ();
  if (n == 0)
    return (char **) NULL;

  char **symbols = new char * [n+1];
  for (int i = 0; i < HASH_TABLE_SIZE; i++)
    {
      symbol_record *ptr = table[i].next ();
      while (ptr != (symbol_record *) NULL)
	{
	  assert (count < n);
	  unsigned my_scope = ptr->is_linked_to_global () + 1; // Tricky...
	  unsigned my_type = ptr->type ();
	  if ((type & my_type) && (scope & my_scope))
	    symbols[count++] = strsave (ptr->name ());
	  ptr = ptr->next ();
	}
    }
  symbols[count] = (char *) NULL;

  if (sort && symbols != (char **) NULL)
    qsort ((void **) symbols, count, sizeof (char *),
	   (int (*)(void*, void*)) pstrcmp);

  return symbols;
}

void
symbol_table::push_context (void)
{
  for (int i = 0; i < HASH_TABLE_SIZE; i++)
    {
      symbol_record *ptr = table[i].next ();

      while (ptr != (symbol_record *) NULL)
	{
	  ptr->push_context ();
	  ptr = ptr->next ();
	}
    }
}

void
symbol_table::pop_context (void)
{
  for (int i = 0; i < HASH_TABLE_SIZE; i++)
    {
      symbol_record *ptr = table[i].next ();

      while (ptr != (symbol_record *) NULL)
	{
	  ptr->pop_context ();
	  ptr = ptr->next ();
	}
    }
}

// Chris Torek's fave hash function.

unsigned int
symbol_table::hash (const char *str)
{
  unsigned h = 0;
  while (*str)
    h = h * 33 + *str++;
  return h;
}

/*
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;;; mode: C++ ***
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;;; End: ***
*/