* List of files

** GNUmakefile

   This is not needed by amrexpr.  This is used to invoke bison and flex to
   generate amrexpr_parser.lex.cpp amrexpr_parser.lex.c, amrexpr_parser.tab.c, and
   amrexpr_parser.tab.h.

** amrexpr_Parser.H & amrexpr_Parser.cpp

   amrexpr_Parser class and ParserExecutor class are the public interface for
   the parser.

** amrexpr_Parser_Exe.H amrexpr_Parser_Exe.cpp

   This is used to compile AST into ParserExecutor, and is used by
   ParserExecutor to compute.  It's not for public use.

** amrexpr_parser.l

   This is a flex file.  Note that this file is not needed to compile amrexpr,
   because the files have already been generated.

** amrexpr_parser.lex.cpp & amrexpr_parser.lex.h

   They are generated by flex.

** amrexpr_parser.y

   This is a bison file.  Note that this file is not needed to compile
   amrexpr, because the files have already been generated.

** amrexpr_parser.tab.cpp & amrexpr_parser.tab.h

   They are generated by bison.

** amrexpr_Parser_Y.H & amrexpr_Parser_Y.cpp

   This turns a mathematical expression given in string format into AST
   using the bison and flex generated code.  This is not for public use.

** Other amrexpr files providing help to Parser