/*

Copyright (C) 1996, 1997 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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA.

*/

#if !defined (octave_lex_h)
#define octave_lex_h 1

// FIXME -- these input buffer things should be members of a
// parser input stream class.

typedef struct yy_buffer_state *YY_BUFFER_STATE;

// Associate a buffer with a new file to read.
extern YY_BUFFER_STATE create_buffer (FILE *f);

// Report the current buffer.
extern YY_BUFFER_STATE current_buffer (void);

// Connect to new buffer buffer.
extern void switch_to_buffer (YY_BUFFER_STATE buf);

// Delete a buffer.
extern void delete_buffer (YY_BUFFER_STATE buf);

// Restore a buffer (for unwind-prot).
extern void restore_input_buffer (void *buf);

// Delete a buffer (for unwind-prot).
extern void delete_input_buffer (void *buf);

// Is the given string a keyword?
extern bool is_keyword (const std::string& s);

// For communication between the lexer and parser.

class
lexical_feedback
{
public:

  lexical_feedback (void) { init (); }

  ~lexical_feedback (void) { }

  void init (void);

  // Square bracket level count.
  int bracketflag;

  // Curly brace level count.
  int braceflag;

  // TRUE means we're in the middle of defining a loop.
  int looping;

  // TRUE means we think we are looking at the beginning of a
  // function definition.
  bool beginning_of_function;

  // TRUE means that we should convert spaces to a comma inside a
  // matrix definition.
  bool convert_spaces_to_comma;

  // TRUE means we're in the middle of defining a function.
  bool defining_func;

  // Nonzero means we are parsing a function handle.
  int looking_at_function_handle;

  // TRUE means we're parsing the return list for a function.
  bool looking_at_return_list;

  // TRUE means we're parsing the parameter list for a function.
  bool looking_at_parameter_list;

  // TRUE means we're parsing a matrix or the left hand side of
  // multi-value assignment statement.
  bool looking_at_matrix_or_assign_lhs;

  // Nonzero means we're parsing an indexing operation for an object.
  int looking_at_object_index;

  // GAG.  Stupid kludge so that [[1,2][3,4]] will work.
  bool do_comma_insert;

  // TRUE means we're doing a raw input command.
  bool doing_rawcommand;
    
  // TRUE means we're looking at an indirect reference to a
  // structure element.
  bool looking_at_indirect_ref;

  // TRUE means that we've already seen the name of this function.
  // Should only matter if defining_func is also TRUE.
  bool parsed_function_name;

  // Are we parsing a nested function?
  //   1 ==> Yes.
  //   0 ==> No.
  //  -1 ==> Yes, but it is the last one because we have seen EOF.
  int parsing_nested_function;

  // Return transpose or start a string?
  bool quote_is_transpose;

private:

  lexical_feedback (const lexical_feedback&);

  lexical_feedback& operator = (const lexical_feedback&);
};

// TRUE means that we have encountered EOF on the input stream.
extern bool parser_end_of_input;

// Flags that need to be shared between the lexer and parser.
extern lexical_feedback lexer_flags;

#endif

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