
*** VDT version 2.6 (release date : 1, December, 1996)

- "raw_value" field of O_literal object is renamed to
  "string" field.

- "bit_string_value" field of L_bit_string object is
  renamed to "string_value" field.

- "int_value" field of L_integer object is renamed to
  "abstract_value" field.

- "float" field of L_float object is renamed to
  "abstract_value" field.

- O_comment object is added as one of VDT objects.

- "initial_expr" fields of O_constant, O_signal, O_variable, and O_file
  are renamed to "expression" field.
   

*** VDT version 2.5 (release date : 31, January, 1996)

- The source files, interface.h, interface.cc are
  renamed to basicMan.h and basicMan.cc, respectively.

- The source files, objman.h and objman.cc are renamed
  to basicSup.h and basicSup.cc, respectively.

- The source files, desman.h and desman.cc are renamed
  to designMan.h and designMan.cc, respectively.
- The source files, libman.h, libman.cc are renamed to
  libraryMan.h and libraryMan.cc, respectively.

- Design object associated to package body is renamed to as follows.
  From (package identifier + "__" )
  To   (package identifier + "__" + package identifier)

- Removed O_ext_ref which is used for external reference.

- Removed L_character which is used as character literal object.

- Removed the field "symbols" of O_context.

- Removed the "search" routine of O_library.

- Added the field "ext_ref" in O_use, instead of removing of
  the field "library", "design_unit", and "suffix".

- Added the "search" routine in O_use.

- Removed a field "ext_refs" of O_context, O_use, O_arch_body,
  O_pack_body, and O_configuration.

- Added a field "function" in objects whose are classified to
  arithmetical operator. The field indicates a O_subprogram
  which is determined by overloading resolution.

- Enabled the automatic creation of implicitly declared subprograms
  for file type and access type.

- Enabled the use of extended graphic character for hangul comment.

- Newly, VHDL static semantic checker was included.

- Many bugs are fixed.


*** VDT version 2.0 (release date : 30, December, 1994)

- The definition of Basic object is located in the files,
  interface.h and interface.cc files.

- The data structure and access routines is defined for
  each kind of Basic object in objman.h and objman.cc files.

- The definition of Design object is located in the files,
  desman.h and desman.cc files.

- The definition of Lib object is located in the files,
  libman.h and libman.cc files.
 
- As VDT utilities, there are VHDL analyzer, VHDL generator,
  VHDL library browse, IF dumper.

