diff lib/Parsers/SimpleCalcYYLexer.pm @ 0:4816e4a8ae95 draft default tip

Uploaded

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/Parsers/SimpleCalcYYLexer.pm	Wed Jan 20 09:23:18 2016 -0500
@@ -0,0 +1,241 @@
+package Parsers::SimpleCalcYYLexer;
+#
+# $RCSfile: SimpleCalcYYLexer.pm,v $
+# $Date: 2015/02/28 20:50:55 $
+# $Revision: 1.9 $
+#
+# Author: Manish Sud <[e-mail]>
+#
+# Copyright (C) 2015 Manish Sud. All rights reserved.
+#
+# This file is part of MayaChemTools.
+#
+# MayaChemTools is free software; you can redistribute it and/or modify it under
+# the terms of the GNU Lesser General Public License as published by the Free
+# Software Foundation; either version 3 of the License, or (at your option) any
+# later version.
+#
+# MayaChemTools is distributed in the hope that it will be useful, but without
+# any warranty; without even the implied warranty of merchantability of fitness
+# for a particular purpose.  See the GNU Lesser General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with MayaChemTools; if not, see <http://www.gnu.org/licenses/> or
+# write to the Free Software Foundation Inc., 59 Temple Place, Suite 330,
+# Boston, MA, 02111-1307, USA.
+#
+
+use strict;
+use Carp;
+use Exporter;
+use Scalar::Util ();
+use Parsers::YYLexer;
+
+use vars qw(@ISA @EXPORT @EXPORT_OK %EXPORT_TAGS);
+
+@ISA = qw(Parsers::YYLexer Exporter);
+@EXPORT = qw();
+@EXPORT_OK = qw();
+
+%EXPORT_TAGS = (all  => [@EXPORT, @EXPORT_OK]);
+
+# Setup class variables...
+my($ClassName, $YYTabFile, @YYLexerTokensSpec);
+_InitializeClass();
+
+# Overload Perl functions...
+use overload '""' => 'StringifySimpleCalcYYLexer';
+
+# Class constructor...
+sub new {
+  my($Class, $Input) = @_;
+  my(@TokensSpec);
+
+  # Initialize object...
+  my $This = $Class->SUPER::new($Input,  @YYLexerTokensSpec);
+  bless $This, ref($Class) || $Class;
+  $This->_InitializeYYLexer();
+
+  return $This;
+}
+
+# Initialize object data...
+#
+sub _InitializeYYLexer {
+  my($This) = @_;
+
+  # Setup default YYTabFile containing mapping of token names to numbers...
+  $This->SetupYYTabFile($YYTabFile);
+
+  return $This;
+}
+
+# Initialize class ...
+sub _InitializeClass {
+  #Class name...
+  $ClassName = __PACKAGE__;
+
+  # Setup default token table file...
+  $YYTabFile = "Parsers/SimpleCalcParser.tab.ph";
+
+  # Setup default lexer tokens specs...
+  @YYLexerTokensSpec = (
+			[ 'LETTER', qr/[a-zA-Z]/ ],
+			[ 'NUMBER', qr/\d+/ ],
+			[ 'SPACE', qr/[ ]*/, sub { my($This, $TokenLabel, $MatchedText) = @_; return ''; } ],
+			[ 'NEWLINE', qr/(?:\r\n|\r|\n)/, sub { my($This, $TokenLabel, $MatchedText) = @_;  return "\n"; } ],
+			[ 'CHAR', qr/./ ]
+		       );
+}
+
+# Is it a lexer object?
+sub _IsSimpleCalcYYLexer {
+  my($Object) = @_;
+
+  return (Scalar::Util::blessed($Object) && $Object->isa($ClassName)) ? 1 : 0;
+}
+
+# Return a string containing information about lexer...
+sub StringifySimpleCalcYYLexer {
+  my($This) = @_;
+  my($SimleCalcYYLexerString);
+
+  $SimleCalcYYLexerString = "SimpleCalcYYLexer: PackageName: $ClassName; " . $This->_GetYYLexerInfoString();
+
+  return $SimleCalcYYLexerString;
+}
+
+1;
+
+__END__
+
+=head1 NAME
+
+Parsers::SimpleCalcYYLexer
+
+=head1 SYNOPSIS
+
+use Parsers::SimpleCalcYYLexer;
+
+use Parsers::SimpleCalcYYLexer qw(:all);
+
+=head1 DESCRIPTION
+
+B<SimpleCalcYYLexer> class provides the following methods:
+
+new, YYLex, GetYYLex, StringifySimpleCalcYYLexer
+
+B<Parser::SimpleCalcYYLexer> class is derived from B<Parser::YYLexer> class, which in
+turn is derived from base class B<Parser::Lexer> that provides all the underlying
+lexer functionality. B<SimpleCalcYYLexer> class is designed to be used with
+B<yyparse> code generated by running B<byacc> on a parser defined using
+parser definition B<SimpleCalcParser.yy> file.
+
+The parser package and token table files, B<SimpleCalcParser.pm> and B<SimpleCalcParser.tab.ph>,
+are automatically generated from parser grammar definition file, B<SimpleCalcParser.yy>, using
+byacc available through perl-byacc1.8 modified with perl5-byacc-patches-0.5 for generation
+of object oriented parser:
+
+    byacc -l -P -d -b SimpleCalcParser SimpleCalcParser.yy
+    mv SimpleCalcParser.tab.pl SimpleCalcParser.pm
+
+B<SimpleCalcYYLexer.pm> class implements a lexer for a simple calculator and is provided
+to highlight usasge of B<YYLex> through B<yyparse>.
+
+The default specification of lexer tokens for B<SimpleCalcYYLexer.pm> includes:
+
+    @YYLexerTokensSpec = (
+        [ 'LETTER', qr/[a-zA-Z]/ ],
+        [ 'NUMBER', qr/\d+/ ],
+        [ 'SPACE', qr/[ ]*/,
+            sub { my($This, $TokenLabel, $MatchedText) = @_; return ''; }
+        ],
+        [ 'NEWLINE', qr/(?:\r\n|\r|\n)/,
+            sub { my($This, $TokenLabel, $MatchedText) = @_;  return "\n"; }
+        ],
+        [ 'CHAR', qr/./ ]
+    );
+
+The default B<SimpleCalcParser.tab.ph> file containing token identifiers for
+B<SimpleCalcParser.yy> includes:
+
+    $NUMBER=257;
+    $LETTER=258;
+
+=head2 METHODS
+
+=over 4
+
+=item B<new>
+
+    $SimpleCalcYYLexer = new Parsers::SimpleCalcYYLexer($Input);
+
+Using specified I<Input>, B<new> method generates a new B<SimpleCalcYYLexer>
+and returns a reference to newly created B<SimpleCalcYYLexer> object.
+
+Examples:
+
+    # Input string...
+    $InputText = "3 + 4 +6\nx=3\ny=5\nx+y\nx+z\n";
+
+    $YYLexer = new Parsers::SimpleCalcYYLexer($InputText);
+    $YYLex = $YYLexer->GetYYLex();
+
+    $Debug = 0;
+    $CalcParser = new Parsers::SimpleCalcParser($YYLex,
+                            \&Parsers::SimpleCalcParser::yyerror, $Debug);
+    $Value = $SimpleCalcParser->yyparse();
+    print "Value: $Value\n";
+
+    # Input file...
+    $InputFile = "Input.txt";
+    open INPUTFILE, "$InputFile" or die "Couldn't open $InputFile: $!\n";
+    $YYLexer = new Parsers::SimpleCalcYYLexer($InputFile);
+    $YYLex = $YYLexer->GetYYLex();
+
+    $CalcParser = new Parsers::SimpleCalcParser($YYLex,
+                            \&Parsers::SimpleCalcParser::yyerror);
+    $Value = $SimpleCalcParser->yyparse();
+    print "Value: $Value\n";
+
+    # Input file iterator...
+    $InputFile = "TestSimpleCalcParser.txt";
+    open INPUTFILE, "$InputFile" or die "Couldn't open $InputFile: $!\n";
+    $InputIterator = sub { return <INPUTFILE>; };
+    $YYLexer = new Parsers::SimpleCalcYYLexer($InputIterator);
+    $YYLex = $YYLexer->GetYYLex();
+
+    $CalcParser = new Parsers::SimpleCalcParser($YYLex,
+                            \&Parsers::SimpleCalcParser::yyerror);
+    $Value = $SimpleCalcParser->yyparse();
+    print "Value: $Value\n";
+
+=item B<StringifySimpleCalcYYLexer>
+
+    $YYLexerString = $YYLexer->StringifySimpleCalcYYLexer();
+
+Returns a string containing information about I<YYLexer> object.
+
+=back
+
+=head1 AUTHOR
+
+Manish Sud <[e-mail]>
+
+=head1 SEE ALSO
+
+Lexer.pm, YYLexer.pm, SimpleCalcParser.yy
+
+=head1 COPYRIGHT
+
+Copyright (C) 2015 Manish Sud. All rights reserved.
+
+This file is part of MayaChemTools.
+
+MayaChemTools is free software; you can redistribute it and/or modify it under
+the terms of the GNU Lesser General Public License as published by the Free
+Software Foundation; either version 3 of the License, or (at your option)
+any later version.
+
+=cut