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+Tom Shields, March 17, 2014
+
+NOTE: README.BTYACC needs to be re-written (or another README file created)
+to explain how the extensions were adopted into the byacc-20140101 baseline.
+
+bytacc changes adopted; see README.BTYACC for details.
+------------------------------------------------------
+
+    Changes to the skeleton to send debugging output to stderr.
+
+    Changes to the types of the grammar tables from 'short' to 'int' if
+MAXTABLE is defined to be > MAXSHORT for generation of large grammar tables
+for large grammars.  This can be set with the invocation of configure
+using the --with-max-table-size=N option
+
+    Changes to add syntactic sugaring for definition and semantic processing
+of inherited attributes associated with non-terminal symbols on the rhs of
+rules.  Inherited attributes are implemented as {}-actions, and as such may
+introduce reduce/reduce conflicts.  The advantage over manual {}-actions is
+that checking is performed on the number and types of inherited attributes,
+and the positions on the semantic stack are automatically calculated.
+Identical actions produced by the inherited attribute syntax are collapsed
+into a single action, reducing reduce/reduce conflicts.
+
+    The %type specification is extended to define the types of inherited
+attributes associated with non-terminal symbols on the lhs of rules, in
+addition to its original purpose in yacc for specifying the type of the
+symbol itself on the parser's value stack.  In order to permit the two
+ aspects to be used independently, the <type> specification following
+%type is optional.
+
+    Added a mechanism to the parser skeleton for computing and propagating
+the text position of grammar symbols if %locations directive is present in
+the grammar specificaion, or if yacc is invoked with the -L flag. Includes
+support for "@$" and "@N" (for N an integer) in actions to refer to symbol
+locations.
+
+    Added a bison compatible %destructor directive to define a memory
+management mechanism to the parser skeleton that enables cleanup of semantic
+values and text positions associated with the parsing stack that are
+automatically discarded during error processing.
+
+The following is only available if configure is invoked with the
+--enable-btyacc=yes:
+
+    Changes to enable backtracking with semantic disambiguation, if yacc is
+invoked with the -B flag.  A yacc parser disambiguates shift/reduce conflicts
+by choosing to shift, and reduce/reduce conflicts by reducing using the
+earliest grammar rule (in the grammar specification).  A btyacc parser handles
+a conflict by remembering the current parse point and entering into trial parse
+mode.  In trial parse mode, the parser tries each of the conflicting options
+until the first successs or until all options are exhausted.  If the parser
+runs into an error while in trial parse mode, it backtracks to the most recent
+conflict point and tries the next alternative.  If the parser finds a
+successful parse, it backtracks to the point where it first entered trial parse
+mode and continues with normal parsing, using the action at the start of the
+successful trial path.  Success in trial parse mode is achieved either by
+successfully reducing the start symbol at the end of input or by invocation of
+YYVALID (or YYVALID_NESTED).  Semantic disambiguation is supported within
+[]-actions, which are always executed, with invocation of YYERROR to terminate
+a trial path or YYVALID (and YYVALID_NESTED).  Yacc {}-actions are only
+executed during normal parsing.
+
+
+btyacc changes deferred:
+------------------------
+
+    The -S command line flag to enable use of an alternate parser skeleton,
+read from an external file.
+
+    Preprocessor statements: %define, %ifdef/%endif, %include.
+
+
+btyacc changes rejected:
+------------------------
+
+    The yyerror_detailed() option for error messages is replaced by the
+byacc feature for specifying options paramters to yyerror().
+
+    C++-specific features in the parser skeleton.