Revision history for Perl extension Eyapp.
1.179
  * No syntactic auxiliary variable will be introduced in the %PREC positions. 
  * Modified the LR parser algorithm:
  * The arguments for the 'code' handler are the parser itself and the conflict name.
  * bug in notation x.y and $x related with explorers
  * two tests with examples/debuggingtut/AmbiguousLanguage2.eyp 
  * tests for perlident in conflict syntaxes using a parser that is in a different directory than the main parser
  * tests for syntax:
                %conflict ToN EMPTY? TYPE:VAR : NAME:VAR
  * tests for syntax 
              %conflict decORexp /regexp/? ID:DEC : ID:EXP
1.178
  * Syntax:
                %conflict ToN EMPTY? TYPE:VAR : NAME:VAR
    see examples/debuggingtut/reducereduceconflictPPCR2.eyp
1.177
  * "Contextual tokens" syntax with nested parsing introduced:
      - %token if   = %/(if)(?!\s*=)/
      - %token if   = %/(if)\b/ !Assign2

  * Added syntax %token = %/regexp/ meaning a contextual token. One that is returned 
    only if expected by the syntax anañyzer. 

            %token then = %/(then)\b/
            %token if   = %/(if)(?!\s*=)/
            %token ID   = /([a-zA-Z_]\w*)/

    See grammar t/PL_I_conflictContextualTokens.eyp

  * Provided syntax:
                  %dummy token TUTU
    Meaning that the token will never be  emited by the lexical generator. 
    See t/dummytoken.eyp
            %syntactic token IF        = /(?i:if)/
            %syntactic token ELSE      = /(?i:else)/
            %syntactic token THEN      = /(?i:then)/
            %token EXPR      = /(?i:(e))/
            %token OTHERSTMT = /(?i:(o))/
            %dummy token TUTU


  * Added to t/77lexicalanalyzergeneration.t a test that uses t/PL_I_conflictContextualTokens.eyp
    to check the syntax 
                        %token X = { code }

                %token then =  { $self->expects('then') and /\Gthen\b/gc     and return ('then', 'then'); }
                %token if   =  { $self->expects('if')   and /\Gif(?!\s*=)/gc and return ('if', 'if'); }
                %token ID  = /([a-zA-Z_]\w*)/
        See t/PL_I_conflictContextualTokens.eyp

  * Provided a higher level API for conflicts that can be solved using nested parsing:
          Cplusplusnested.eyp:
              %conflict decORexp decl? ID:DEC : ID:EXP

              It means: Check for nested parser "decl" if success, reduce by 'ID:DEC', otherwise
              reduce by 'ID:EXP'
          pascalnestedeyapp3_6.eyp:
              %conflict rORe range? ID:RANGE : ID:ENUM
          DebugDynamicResolution4.eyp:
              %conflict LD lastD? D:LAST : shift

              It means: Check for nested parser "lastD" if success, reduce by 'D:LAST', otherwise
              shift

  * YYSetReduce can work without specifying the token set
  * YYSetShift can work without specifying the token set
1.176
  * A shift-reduce conflict example solved with 'pure' PPCR in DebugdynamicResolution4.eyp
  * %conflict C symbol? prod : prod
      - symbol is no necessarily a symbol of the grammar

      - VIEWPOINT in the body, i.e. symbol? must be optional. 
      In such case the nested parsing is made inside the conflict solver
      See lastD.eyp and DebugDynamicResolution4
  * Tests in t/88explorer.t for the new %explorer and %conflict syntax!
       - DebugDynamicResolution.eyp
       - dynamicgrammar1.eyp
       - reducereduceconflictPPCR.eyp
       -  ExpList.eyp, reuseconflicthandler.eyp, noPackratSolvedExpRGconcept.eyp
       - CplusplusNested.eyp
       - pascalnestedeyapp3_5.eypp
  * Conflict resolution syntax:
                    %conflict rORe range? ID:RANGE ID:ENUM
   
  * No warnings with -c in 
        eyapp -C CplusplusStartOption
    check this bug!!!!
    Make a test!  85minusSoption.t
     
    May be the nested parser can be embedded in the same module generated without requiring
    a second compilation with -S start -P
1.175
  - Tests for png
1.174
      - eyapp -S C etc. will generates a %start C directive and warnings will be supressed
       if no -m the default will be "decl.pm" i.e. the start symbol will name the module

1.173
    -- Merged PPCR branch with trunk
    -- option for main to produce .png version of the AST
    -- png for .output also: options -w and -W
    -- improved $t->png to include attribute info
    -- $t->png: order of the children is respected
1.171
   * .dot file describing the LR tables generated with options -w and -W
      - Option -W visualize with kernel items
      - Option -w visualize without kernel items
      - visualize conflicts
   * vgg removed
   * dynamicgrammar. There was a bug
        check inside YYSetReduce if the next states is a truly conflict state

        save the conflict states at compile time
        and send them to the parser,
        then inside YYsetReduce, check that the next state is inside
        the listed conflict states

    * $t->png etc. for trees implemented 
1.170

  * Expected and language generation for article 

  * add to YYPreParse one option for debugging the preparsing.
    idem for other options
  * GeneratorF.eyp forbid division by zero error in the generated expressions
  *TokenGen::generate 
    Check for existence of arg yylex or set to reasonable defaults
  * Write Test::LectroTest::Generator::Grammar

  *YYSymbolStack: there is no need to copy the stack each time. 
   Saving the position is enough

  * add parsing strings and trees as a test

  * An important bug while computing YYExpected was fixed
  * Added data generation as a test

1.169
  * Clusplus example. Start from the documentation. For Luis
    see file tt2/cplusplus

  * This important bug was fixed: 
    There is s.t. wrong in reuseconflicthandler.eyp and 
    noPackratSolvedExpRGconcept.eyp. why is it that we have to specify
    a reduction by 'end of input' when there is no conflict for such 
    token?????

  * test t/80 with Cplusplus

1.167
  Bug solved:
    my $ID = qr{...};
    token ID = /$ID/
    the code for my $ID went after the lexer. That was an error.

   * Syntax for conflicts include an explorer (pre-parser/nested parsing)

        T: %isInTheMiddle? S
        ;

        S:
             x  %PREC isInTheMiddle S x  
          |  %name :MIDx 
             x  %PREC isInTheMiddle 
        ;

1.165
  * New syntax %explorer CONFLICTNAME { ... }
    See examples in examples/debuggintut
      noPackratSolvedExpRGconcept.eyp

  * t/66yydebugstandaloneandpod.t: test debug mode and output of "stack symbols"
  * Removed pushing the token values in the stack. Keep it only while debugging
  * Removed (temporary) -S option from eyapp
  * Test t/80ppcr.t checks PPCR with YYPreParse
  * Original API for PPCR deprecated:
      - # sub YYLookBothWays {
      - # sub YYSymbolStack {
  
1.156
  * given explicit precedence to tokens
       %token LASTSEMICOLON /(;)(?=S)/
       %token ';' 
  * bug fixed: YYPrefix and main method (info methods did not work if YYPrefix was active)
1.155
  * A default lexer is built that can be used when no lexer is provided
  * eyapp -v option implies -N option

  * YYSymbolStack(0,-k) string with symbols from 0 to last-k
    YYSymbolStack(-k-2,-k) string with symbols from last-k-2 to last-k
    YYSymbolStack(-k-2,-k, filter) string with symbols from last-k-2 to last-k
                                   where filter can be code, regexp or string
    YYSymbolStack('SYMBOL',-k, filter) string with symbols from the last occurrence of SYMBOL to last-k
                                   where filter can be code, regexp or string

  *  - Now YYSymbol(-k) provides the symbol associated with the k-th state
       from the top of the parsing stack 
     - The debug format (yydebug activated) shows the transition symbols in the stack
     - The parsing stack stores the transition symbols
     - See file code/reducereduceconflictPPCR.eyp for a way to use it when solving conflicts

  * There was a bug in the tree directive when there was a token 
    with name 'something' and a syntax variable with the same name 
    something. Seems fixed. See t/75tokenandvariablewiththesamename.t

  * Added option -N (nocompact) to eyapp.
    The compacted output info about conflicts in the .output file isn't
    detailed enough. It does not describes in full detail which tokens
    and productions are involved

  * Labels only after %name accepted

  * -B prompt eyapp option added

  *  -yml option in Parse::Eyapp::Driver::main to dump YAML 

  * -C option == -B '' and -b ''

  *  While %lexer provides $self, %conflict did not. Now consistent. $self is 
     $_[0] (but the arg isn't shifted)

  * option -T for eyapp

  *  #line in dynamic conflict handlers

  * Ambiguous calc example: exp: exp '-' exp with precedences dynamically changed by the user (LEFT, RIGHT).
    See file: examples/debuggintut/dynamicgrammar.eyp


1.154
  * option to define the info function (for array and plain scalars)
1.153
  * %expect-rr
  * labels and names %name in recycle fixed. See example examples/recycle/rewritepostfixwithactions.pl

1.152
  * Parse::Eyapp::Base was removed from standalone parsers
  * lexer, input and error as static/class attributes and inheritance
  * Parse::Eyapp::TailSupport embedded in Driver 
  * if lex or error are already set don't ask for then in YYParse
  * label for names %name B:A (label is A, name is B). A conflict can refer to 
    the  name:label but the class is 'name'

  * Dynamic conflict  resolution:
      %conflict CONFLICTIDENTIFIER { # conflict solver
               if (is_A()) { $self->YYSetReduce('@', 'ruleA') }
               else { $self->YYSetShift('@') }
      }

      A: alpha  %PREC CONFLICTIDENTIFIER


1.137
  %nocompact
    This directive disables the optimization of using the DEFAULT field of the actiontable
    and keeps the follows.  Is in Lalr.pm in sub _SetDefaults. 
1.136
    %namingscheme : defines an automatic naming cheme 
1.134 - -b now set the permits. Useful to make a modulino
1.121 - Standalone wasn't working: Parse::Eyapp::Base must be included
1.118 - new with yyprefix
      - Avoided dependence of List::MoreUtils. It broke Eyapp in some architectures
1.112 - Hal Finkel's patch for alias
1.107 - Option lib in treereg
1.106 Thu jan 17 09:31:24 WET 2008
     - Documentation of Parsse::Eyapp::Base 
     - pop_method does not modifies the methods when its stack is empty
1.104 Mon jan 14 18:42:11 WET 2008
     - Base.pm expanded with pus_method and pop_method. Documentation for Base.pm
       aded

Previous pre-eyapp history

	- original version; created by h2xs 1.18
0.01  Thu Jun 25 20:02:09 1998
0.02  Never released
0.03  Never released
0.04  Never released
	- Fix installation of yapp.pl to $INST_SCRIPT
	- $VERSION is now in Yapp/Driver to check compatibility
	- Add debugging driver and debug option
	- Bug in error recovery fixed: do not shift an $error reduction
	- Add LeftValue, Curtok and Curval methods
	- Add driver version compatibility check 
0.05  Thu Jul 03 20:05:05 1998
	- Add LeftValue, Curtok and Curval methods
0.06  Tue Jul 07 20:36:17 GMT 1998
    - Error token '$error' becomes 'error' (like in yacc)
    - The '$end' token becomes ''
0.07  Never released
    - Default action become a separate entry in states hash
    - $COMPATIBLE value changed to 0.08
    - The grammar parser is now a Yapp parser module
    - Comments can be either Perl (#...\n) or C /* ... */ style
    - The parser accepts %type, %union and <type> constructs and
      almost ignore them, except checking consistency between token
      and non-terminal declarations (warnings)
    - The parser now has error recovery and consistent error line numbers
    - The parser now accepts "in rule" actions and generates pseudo
      empty rules to reduce, named @x-y, where x is a sequential
      number and y the 'dot position' in the rule for the driver
      to know how many parameters to pass to semantic action sub
    - Add "in rule" actions handling in Driver.pm
    - Empty rhs need not be the first one anymore
    - Warning if more than one empty rhs for a given lhs
0.08  Fri Jul 10 22:04:31 GMT 1998
    - Changed 'print STDERR' to 'warn' in parser.
    - Use of literal 'error' produces a warning and is treated as
      the error token
    - Add prefix 'YY' before each parser object methods to avoid
      clashes with user written methods
    - Renamed YYUserData to YYData (shorter and more consistent with
      other methods names)
    - Renamed YYLeftVal to YYSemval for same reasons
    - Modified Driver.pm so Semval(-n..n) reacts like $-n..$n in yacc
0.09  Never released
    - Changed test suite to 't/' style and add base tests for semantic
      actions/values and associativity tests
    - Check code to be (almost) Perl's -w compatible
    - Updates to pod section in Yapp.pm reflecting most of those changes
0.10  Mon Jul 13 20:53:40 GMT 1998
    - Cosmetic changes
0.11  Wed Jul 15 19:46:17 GMT 1998
    - Renamed Yapp::Parse parameters with a leading yy
    - Updated Yapp.pm pod section
0.12  Tue Jul 21 22:34:00 GMT 1998
0.13  Never released. (I'm not supersticious, but who knows...8-))
    - Renaming to Parse::Yapp for better CPAN entry...
0.14  Wed Jul 29 21:43:03 GMT 1998
    - Doc change: empty token is '', not undef (perl -w complains otherwise)
    - Bug in _ReduceGrammar: used $ruleno instead of $#{$grammar{RULES}}
      making no-terminal pointing to wrong rhs if useless rules.
0.15  Mon Aug 17 11:39:01 CEST 1998
    - YappParse.yp modified to allow empty tail section (not even \n)
    - YappParse.yp modified to diagnose lack of rules in grammar section
    - Driver.pm has been modified so there is no performance impact at
      loading when debugging is not used and to insure thread safety at
      runtime
    - Output.pm can now include driver code into the parser module to
      make it 'standalone'
    - Copyright notice in Driver has been changed to reflect its use
      if included in a standalone parser
    - A -s option has been added to yapp.pl to generate standalone parsers
    - Usage in yapp.pl reflects this new option 
    - Updated Yapp.pm pod to add Standalone Parsers item
0.16  Sun Oct 25 12:36:05 CET 1998
    - Output.pm modified not to use DATA handle, which seems broken on windows
      systems when Parse::Yapp module is untarred and Output.pm hasn't its \n
      converted to \r\n pairs.
    - Added the %expect declaration, a la bison
    - Updated Yapp.pm pod to reflect this new option
    - The core of Parse::Yapp seems very stable now so I change the status from
      alpha to beta and jump to version 0.20 directly.
0.20  Sun Dec 20 16:13:21 CET 1998
    - Added YYExpect method in Parse/Yapp/Driver.pm
    - Updated Yapp.pm pod to reflect this new method
    - Modified Makefile.PL for using current Parse::Yapp version if recompiling
      Parse/Yapp/Parse.pm from YappParse.yp ( $(PERL) -I. )
    - Modified yapp.pl to add -V option and make output default to final name
      of package, if -m option is specified. Usage updated.
    - Added missing $@ check after eval of debugging driver.
0.21  Thu Dec 24 17:55:47 GMT 1998
    - Corrected a weird bug in Lalr.pm (_SolveConflicts & _SetDefaults) about
      shift/reduce conflicts on non-associative tokens
    - Added a test in base.t to check non-associative conflicts and error
      token handling
    - Added some doc to explain YYExpect can include YYCurtok when non-associ-
      ative errors happen
0.22  Wed Mar 10 17:03:39 CET 1999
    - Moved Parse path tree under lib to be conformant with standard Perl
      modules distributions
    - Added Parse::Yapp::Options class as parent of Parse::Yapp::Grammar
      to handle various options.
    - As the Output method is not really 'public' yet, it now takes its
      arguments as hash list, like YYParse. Can break code of people not
      using the yapp.pl front-end.
      Of course, its arguments are handled by Parse::Yapp::Options
    - Added #line "inputfile" trace in generated grammar by default for input
      source line numbers (obvious reason for adding that :-).
    - Added language, linenumbers, inputfile, classname, standalone and input
      options which default to ( 'Perl', 1, undef, 'Parser', 0, undef )
    - Modified yapp.pl for new parameter list
    - Idem for t/base.t and t/calc.t
    - Modified Grammar.pm so it uses linenumbers option to know it must output
      line numbers and inputfile as the filename. If inputfile is undef, then
      use 'unkown'.
    - Added a new flag -n to yapp.pl to disable line numbers in parser output
    - Renamed yapp.pl to yapp (bored of typing .pl)
    - Wrote pod for yapp frontend (so now there's a man 1 page !)
    - Added article in copyright notice when using the standalone parser option
0.30 Sat Apr  3 15:36:58 CEST 1999
    - Corrected a silly bug in yapp front-end, calling Output method with
      inputfile parameter, which was already done with the constructor
    - Change to yapp frontend so the F<*.output> file goes to the same
      directory than the F<*.yp> source file
    - Corrected Head method in Parse::Yapp::Grammar so it returns '' if there
      is no header code, to avoid a warning with perl's -w switch
    - Same for Tail method, so no line number is output if there is no trailer
      code
    - Corrected a bug in Grammar.pm, to make useful rules useless if their lhs
      are not reachable.
0.31 Fri May  7 21:06:32 CEST 1999
    - Won some milliseconds in Driver.pm by not calling an anonymous sub if
      there is no semantic action: just get the first semantic value as result
    - Added a patch from Andy Wardley (thanks) which allow people to specify
      their own template rather than the standard one from Output.pm
    - Added option C<-b> to yapp to specify a 'shebang'. If value is an empty
      string, $Config{perlpath} is used.
1.00 Wed Oct 20 17:52:38 CEST 1999
    - Corrected a bug in Options.pm to have it run with Perl 5.6.0 
1.01 Tue Mar 28 18:50:19 CEST 2000
    - In YappParse.yp, if declaring a token with %left/%right/%nonassoc and
      later redefining it with token lost precedence/associativity. Now, it
      emits a warning
    - In Lalr.pm, _FirstSfx, incorrectly looped when epsilon was in firstset
      instead of beeing nullable (this one was weird)
    - In Driver.pm, check for a call to YYErrok after calling error routine
      to abort error recovery and continue normal parsing 
    - New method YYLexer added in Driver.pm, to get a reference to the lexer
      routine
    - In Driver.pm, $check variable was not always cleaned up
1.02 Mon May  1 13:42:03 CEST 2000
    - English corrections in README file (thanks to Donald Lancon)
	- New email address
	- Updated copyright boundaries
	- Various cleanups in Grammar.pm and Lalr.pm
1.03 Sun Nov  5 13:14:49 CEST 2000
    - In Lalr.pm, _Preds, recursivity removed
    - English corrections in Parse::Yapp pod section (thanks to Julian Trudy)
	- Updated copyright boundaries
    - Stress test added (compile and check a full C++ grammar)
1.04 Mon Feb 12 16:46:37 CET 2001
    - Bug correction in YappParse.yp _Lexer sub to accept '\\' litterals
      (Thanks to Denis Barbier to catch this one)
1.05 Sun Nov  4 20:32:32 CET 2001
