history

一个Pascal语言分析器

Change History since version 1.21
=================================

Version 1.22 - internal, not released

Version 1.23 - Sun  05-31-1992

-   Updated and corrected documentation.
-   Scanner now returns "sym" of CARDINAL not INTEGER type.
-   Frame files modified to handle this change.
-   CRP.MOD and CRS.DEF and CRS.MOD modified to handle this change.
-   CRX.GenCond modified to handle small sets more safely.
-   CRS.NextCh in scanner now translates CHR(26) to CHR(0) so that DOS
    editors that append CHR(26) to text files will not cause problems.
-   Modified CHARACTERS definition on CR.ATG to allow only printable
    characters in strings (in particularly preventing strings from extending
    over more than one line).
-   Corrected errors in FileIO.WriteText in all four versions.
-   Corrected bug in CRA.ImportSymConsts that was generating too long a name
    for the generated Symbolic constants file.
-   Improved CRL.PrintErr to remove redundant parameter.
-   Fixed CRL.GetLine to ensure that CHR(26) was treated properly.

Version 1.24 - Mon  06-15-1992

-  Changed the $C pragma to $N (Names).  C had no mnemonic content!
-  Updated and corrected documentation.
-  Modified parser generation to avoid exporting symSetSize from the
   definition module.
-  Modified scanner yet again to convert CHR(26) to CHR(0) whenever found
   (thus avoiding problems caused by DOS editors that add CTRL-Z to the ends
   of text files more systematically).
-  Added pragma/command line option to allow suppression of definition module
   generation (recreating these each time means all clients have to be
   recompiled every time, which is tedious).
-  Added pragma/command line option to allow optional creation of a complete
   driver program (using frame file COMPILER.FRM) which incorporates a list
   handler with interleaved error messages.  A simple COMPILER.FRM is supplied
   that is "generic", but needs to be adapted for most applications.  Special
   tuned cases of COMPILER.FRM are provided for the sample grammars in the
   kit.
-  Modified the output directed to file <Grammar>E.TXT slightly.
-  Rearranged CRT.DEF and CRT.MOD to eliminate a superfluous procedure
   (PrintSet no longer exported, PrintSetTerminal eliminated).
-  Rearranged order of generation of def and imp mods for scanner and parser,
   and made minor changes to SCANNER.FRM and PARSER.FRM.
-  Moved export of "directory" and "lst" to scanner module CRS.DEF, and
   eliminated CRL.DEF and CRL.MOD.  The list handling is now handled in
   CR.MOD.
-  Various minor changes to CR.MOD made to reflect all these changes in the
   help screen, etc.

Version 1.25 - Sat  06-20-1992

- Minor bug in COMPILER.FRM files repaired

Version 1.26 - Wed  08-26-1992

- Rearranged COMPILER.FRM files to incorporate error/list handler as
  internal module.
- Replaced curious WriteText call in error/list handler with WriteString.
- Repaired bug in CRT.MOD to handle generation of names for terminals with
  single quotes   (Thanks to Tim Channon for pointing this one out!).

Version 1.27 - Tue  10-06-1992

- Extended length of name field in CRT.DEF to 40 chars.
- resultant small changes in output format in CRT.
- fixed bug in symbolic name generation for terminals with non-letters in
  them.
- suppressed generation of GrammarG.DEF along with other DEF mods when
  suppression requested.
- allowed COMPILER.FRM to default first to GRAMMAR.FRM in grammar directory
  (Thanks to Tim Channon for suggestion).
- fixed silly error in SCANNER.FRM that cause errors on first line to be
  reported in the wrong places.
- improved COMPILER.FRM files to treat tabs as spaces in error listing and
  thereby line up error messages more accurately (still needs improving).

Version 1.28 - Fri  04-30-1993

- Fixed bug in Term that resulted in program looping if alternatives in
  productions also involved unrecognisable tokens (Thanks to John Gough
  for discovering the bug).

Version 1.29 - Tue  07-13-1993

- Fixed various places where BITSET was omitted in front of default {} set
  constructors - this will be needed in some implementations.
- Changed WriteInt(f,x,0) calls to WriteInt(f,x,1) calls in various places
  (New standard requires ,0 to generate exactly one leading space).

Version 1.30 - Sat  08-07-1993

- Fixed bug that regarded two terminals like 'hello' and "hello" to be
  regarded as distinct (Thanks to Stuart van Onselen for spotting this one).
  Terminals typed as 'singlequoted' are now converted internally to
  "doublequoted" (except, obviously, where a double quote appears within
  'single"quoted"strings').

Version 1.31 - Sat  08-21-1993

- Various nasties.  Thanks to John Gough who pointed out an abuse of CRT.Set
  in CRA.DeleteRedundantStates.  In chasing this and testing on grammars that
  yield large numbers of states, various other problems came to light.  Moved
  the symbol table to the heap (CRT) and extended various limitations.
  CRA.GetstateSet was rewritten to conform to the Oberon Sources I have, and
  this seems to clear a nasty problem in melting states.  A lurking bug in
  MakeUnique has not yet been fully tracked.  Compiler restriction messages
  and CRX.WriteStatistics improved and extended.  Thus CRA, CRX and CRT have
  all been changed.

  Considering change to FileIO to replace "con" with StdIn and StdOut.

Version 1.32 - Sat  09-04-1993

- Major overhaul of CRA and CRS following debugging exercise by Hanspeter
  Moessenboeck in Zurich.  Hopefully this has cleared the automaton problems.
  His Oberon changes were adapted for the Modula-2 version, needing
  slight changes.  Also fixed potential problem in SCANNER.FRM to prevent
  garbage being produced on attempts to read past the end of the source buffer.

Version 1.33 - Tue  12-14-1993

- Further bug fixes in CRA following fixes by Hanspeter Moessenboeck.
- Minor adjustments to sources to incorporate place holders for changes needed
  to port to Gardens Point Modula-2 versions.
- Gardens Point versions of FileIO and Strings added to kit (see directory
  SOURCES\GPM; thanks to John Gough of the Queensland University of Technology
  for making these available).
- Shareware versions first made available on ftp servers world wide.  These
  include the MS-DOS kit and the complete Gardens Point Modula kit for UNIX
  implementations.

Version 1.34 - Tue  01-11-1994

- More corrections to CRA to handle (disallow) tokens starting with an
  iteration.

Version 1.35 - Thu  05-19-1994

- Corrections to CRX.MOD to fix bug reported by Frankie Arzu.
- Alterations to frame files, and to CRA.MOD and CRS.MOD to allow Coco/R
  to handle input files with line breaks in any of MS-DOS, Unix, or MAC
  formats.  Note that the output is generated in the "local" format.
- Added simple CONVERT utility to be able to convert text files from one of
  these forms to any other.
- Took advantage of opportunity to improve formatting of generated parser.

Version 1.36 - Thu  06-02-1994

- Corrections to CRA.MOD to allow for proper handling of CONTEXT clauses.
- Improved portability in the generated scanners still further.
- Alternative scanner frame provided for small source programs.

Version 1.37 - Thu  07-07-1994

- Fixed FileIO.MOD to allow widths of 0 to behave as specified (ie to give
  a leading space.

Version 1.38 - Thu  04-27-1995

- Fixed CRX.MOD to handle problem with Logitech implementation of file
  closing.
- Changed COMPILER.FRM (and other frame files) to allow better handling of
  tabs within source ATG files.

Version 1.39 - Tue  10-03-95

- Fixed command line use to allow
         COCOR [-options] Grammar
  as alternative to
         COCOR Grammar /Options
  so as to match Un*x usage.
- Tokens that have spaces within them are detected and reported.
- Changed output of FORWARD declaration suppression.
- Added a CRQ.FRM file to the MS-DOS kit to allow generation of a version that
  writes error messages in "FileName (Line, Col)" format for use with editors
  that can interface to such messages.
- Removed a SET OF CHAR that had crept in and which is non-portable to some
  older compilers.
- Redefined FileIO.def to act as a single interface to as many non-portable
  or awkward features as possible, including the interface to minimal set
  of Strings routines.
- Added StdIn and StdOut to exports from FileIO to allow for proper handling
  of redirected I/O.
- FST, JPI, StonyBrook Logitech and GPM-PC implementations of FileIO
  completely overhauled.  Implementations added for Mocka Linux and BSD.
  Implementations overhauled for Gardens Point implementations (tested
  on Linux and Mocka versions of Gardens Point only).
- Implementation added for generating Turbo Pascal (thanks to Volker Pohlers)
- A great many other small changes to sources to enhance portability.
- Suppressed timing output.
- Added several more example grammars.
- Fixed bug in Mod2.atg and PimMod.atg.

Version 1.40 - Mon  06-10-96

- Added LexName, LexString, LookAheadName, LookAheadString to Parser module
  for easier extraction of current lexeme.
- Added Successful to Parser for easier assesment after parsing is complete.
- Added SynError and SemError procedures to interface of Parser module, so
  that they can easily be called from the semantic routines provided in the
  ATG file.  Semantic errors with are reported at the current, rather than the
  lookahead symbol position.  Users must choose error numbers greater than any
  generated automatically bu Coco/R.  Start them high (>=1000 say)
  This meant a small change to the
  CRX and CRC modules, and some minor changes to the frame files.
- Various minor bug fixes.
- Many thanks to Frankie Arzu, whose work on the C++ version inspired many of
  these changes.

Version 1.41 - 08-16-96

- Fixed minor bug in comment generation

Version 1.42 - Tue  10-28-97

- Prevent grammars from specifying IGNORE CHR(0)
- Documentation updated to conform more closely to that found in my textbook
  "Compilers and Compiler Generators - an introduction with C++" which uses
  Coco/R extensively (published by International Thomson; ISBN 1 85032 298 8).
  Although the text's examples are mainly in C++ (not much else, other than
  Java, sells books these days) the source code on an accompanying diskette
  has equivalent Modula-2, Pascal and C++ for every example.  This code is
  available for ftp from cs.ru.ac.za:pub/languages/textbook
- Minor changes made to compiler frame files (Pascal versions only) to
  eliminate stray NUL characters in the .LST files (Thanks to Kenneth Stout
  for pointing this out).
- Fixed bug relating to closure formation when finding FIRST and FOLLOW sets
  (Thanks to Kenneth Stout for detecting this, and to Hanspeter Moessenbock
  for fixing it *)

Version 1.43 - Monday  05-18-98

- Minor cosmetic changes to keep abreast of changes to Modula-2 version as
  this was adapted to use ISO Modula-2.  Some redundant code excised
- Errors now written to Grammar.ERR and not to GrammarE.TXT
- Comments may now be written /* as in C */ as (* well as in Modula/Pascal *)
- Underscores permitted in identifier names - use carefully!

Version 1.44 - Tuesday  06-16-98

- Minor cosmetic changes to adapt code to allow for greater consistency with
  Java version; a few minor bugs fixed in comment handling.
- Taste package slightly improved

Version 1.45

- Subtle bug in CRA module repaired thanks to Hanspeter Moessenboeck

Version 1.46 Sun  08-23-98

- Fixed bug in use of high ASCII characters in strings
- Literal token strings of zero length no longer allowed

Version 1.47 Wed  11-04-98

- Eliminated allowing incomplete strings within attributes and actions
- Minor improvements to documentation
- Duplicate case label fixed in CRTABLE.PAS (non detection of this represents
  a bad Turbo Pascal bug).  Thanks to Gale Paeper for finding it.

Version 1.48 Fri  07-09-99

- Attributes may now be demarcated by matching <. and .> or by < and >.  This
  extension allows for the > character to appear in an actual parameter.
- Omitting the closing .) in an action can lead to errors that are hard to
  find, so the digraph (. appearing within a semantic action is now flagged as
  an error (Thanks to Hans Ellenberger for this suggestion).

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