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|  | 13 <pre> | 
|  | 14 <a name="package-Parsers::Lexer-"></a>   1 <span class="k">package </span><span class="i">Parsers::Lexer</span><span class="sc">;</span> | 
|  | 15    2 <span class="c">#</span> | 
|  | 16    3 <span class="c"># $RCSfile: Lexer.pm,v $</span> | 
|  | 17    4 <span class="c"># $Date: 2015/02/28 20:50:55 $</span> | 
|  | 18    5 <span class="c"># $Revision: 1.10 $</span> | 
|  | 19    6 <span class="c">#</span> | 
|  | 20    7 <span class="c"># Author: Manish Sud <msud@san.rr.com></span> | 
|  | 21    8 <span class="c">#</span> | 
|  | 22    9 <span class="c"># Copyright (C) 2015 Manish Sud. All rights reserved.</span> | 
|  | 23   10 <span class="c">#</span> | 
|  | 24   11 <span class="c"># This file is part of MayaChemTools.</span> | 
|  | 25   12 <span class="c">#</span> | 
|  | 26   13 <span class="c"># MayaChemTools is free software; you can redistribute it and/or modify it under</span> | 
|  | 27   14 <span class="c"># the terms of the GNU Lesser General Public License as published by the Free</span> | 
|  | 28   15 <span class="c"># Software Foundation; either version 3 of the License, or (at your option) any</span> | 
|  | 29   16 <span class="c"># later version.</span> | 
|  | 30   17 <span class="c">#</span> | 
|  | 31   18 <span class="c"># MayaChemTools is distributed in the hope that it will be useful, but without</span> | 
|  | 32   19 <span class="c"># any warranty; without even the implied warranty of merchantability of fitness</span> | 
|  | 33   20 <span class="c"># for a particular purpose.  See the GNU Lesser General Public License for more</span> | 
|  | 34   21 <span class="c"># details.</span> | 
|  | 35   22 <span class="c">#</span> | 
|  | 36   23 <span class="c"># You should have received a copy of the GNU Lesser General Public License</span> | 
|  | 37   24 <span class="c"># along with MayaChemTools; if not, see <http://www.gnu.org/licenses/> or</span> | 
|  | 38   25 <span class="c"># write to the Free Software Foundation Inc., 59 Temple Place, Suite 330,</span> | 
|  | 39   26 <span class="c"># Boston, MA, 02111-1307, USA.</span> | 
|  | 40   27 <span class="c">#</span> | 
|  | 41   28 | 
|  | 42   29 <span class="k">use</span> <span class="w">strict</span><span class="sc">;</span> | 
|  | 43   30 <span class="k">use</span> <span class="w">Carp</span><span class="sc">;</span> | 
|  | 44   31 <span class="k">use</span> <span class="w">Exporter</span><span class="sc">;</span> | 
|  | 45   32 <span class="k">use</span> <span class="w">Scalar::Util</span> <span class="s">(</span><span class="s">)</span><span class="sc">;</span> | 
|  | 46   33 | 
|  | 47   34 <span class="k">use</span> <span class="w">vars</span> <span class="q">qw(@ISA @EXPORT @EXPORT_OK %EXPORT_TAGS)</span><span class="sc">;</span> | 
|  | 48   35 | 
|  | 49   36 <span class="i">@ISA</span> = <span class="q">qw(Exporter)</span><span class="sc">;</span> | 
|  | 50   37 <span class="i">@EXPORT</span> = <span class="q">qw()</span><span class="sc">;</span> | 
|  | 51   38 <span class="i">@EXPORT_OK</span> = <span class="q">qw()</span><span class="sc">;</span> | 
|  | 52   39 | 
|  | 53   40 <span class="i">%EXPORT_TAGS</span> = <span class="s">(</span><span class="w">all</span>  <span class="cm">=></span> <span class="s">[</span><span class="i">@EXPORT</span><span class="cm">,</span> <span class="i">@EXPORT_OK</span><span class="s">]</span><span class="s">)</span><span class="sc">;</span> | 
|  | 54   41 | 
|  | 55   42 <span class="c"># Setup class variables...</span> | 
|  | 56   43 <span class="k">my</span><span class="s">(</span><span class="i">$ClassName</span><span class="s">)</span><span class="sc">;</span> | 
|  | 57   44 <span class="i">_InitializeClass</span><span class="s">(</span><span class="s">)</span><span class="sc">;</span> | 
|  | 58   45 | 
|  | 59   46 <span class="c"># Overload Perl functions...</span> | 
|  | 60   47 <span class="k">use</span> <span class="w">overload</span> <span class="q">'""'</span> <span class="cm">=></span> <span class="q">'StringifyLexer'</span><span class="sc">;</span> | 
|  | 61   48 | 
|  | 62   49 <span class="c"># Class constructor...</span> | 
|  | 63 <a name="new-"></a>  50 <span class="k">sub </span><span class="m">new</span> <span class="s">{</span> | 
|  | 64   51   <span class="k">my</span><span class="s">(</span><span class="i">$Class</span><span class="cm">,</span> <span class="i">$Input</span><span class="cm">,</span> <span class="i">@TokensSpec</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> | 
|  | 65   52 | 
|  | 66   53   <span class="c"># Initialize object...</span> | 
|  | 67   54   <span class="k">my</span> <span class="i">$This</span> = <span class="s">{</span><span class="s">}</span><span class="sc">;</span> | 
|  | 68   55   <span class="k">bless</span> <span class="i">$This</span><span class="cm">,</span> <span class="k">ref</span><span class="s">(</span><span class="i">$Class</span><span class="s">)</span> || <span class="i">$Class</span><span class="sc">;</span> | 
|  | 69   56   <span class="i">$This</span><span class="i">->_InitializeLexer</span><span class="s">(</span><span class="s">)</span><span class="sc">;</span> | 
|  | 70   57 | 
|  | 71   58   <span class="i">$This</span><span class="i">->_ValidateParametersAndGenerateLexer</span><span class="s">(</span><span class="i">$Input</span><span class="cm">,</span> <span class="i">@TokensSpec</span><span class="s">)</span><span class="sc">;</span> | 
|  | 72   59 | 
|  | 73   60   <span class="k">return</span> <span class="i">$This</span><span class="sc">;</span> | 
|  | 74   61 <span class="s">}</span> | 
|  | 75   62 | 
|  | 76   63 | 
|  | 77   64 <span class="c"># Initialize class ...</span> | 
|  | 78 <a name="_InitializeClass-"></a>  65 <span class="k">sub </span><span class="m">_InitializeClass</span> <span class="s">{</span> | 
|  | 79   66   <span class="c">#Class name...</span> | 
|  | 80   67   <span class="i">$ClassName</span> = <span class="w">__PACKAGE__</span><span class="sc">;</span> | 
|  | 81   68 <span class="s">}</span> | 
|  | 82   69 | 
|  | 83   70 <span class="c"># Initialize object data...</span> | 
|  | 84   71 <span class="c">#</span> | 
|  | 85 <a name="_InitializeLexer-"></a>  72 <span class="k">sub </span><span class="m">_InitializeLexer</span> <span class="s">{</span> | 
|  | 86   73   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> | 
|  | 87   74 | 
|  | 88   75   <span class="c"># Input parameter used by lexer to retrieve text to be lexed. Supported parameter types:</span> | 
|  | 89   76   <span class="c">#   . Reference to input iterator function</span> | 
|  | 90   77   <span class="c">#   . Reference to an open file handle</span> | 
|  | 91   78   <span class="c">#   . Text string</span> | 
|  | 92   79   <span class="c">#</span> | 
|  | 93   80   <span class="i">$This</span>->{<span class="w">Input</span>} = <span class="k">undef</span><span class="sc">;</span> | 
|  | 94   81 | 
|  | 95   82   <span class="c"># Type of input paramater determined using Perl ref function:</span> | 
|  | 96   83   <span class="c">#   . InputIterator - ref returns CODE</span> | 
|  | 97   84   <span class="c">#   . FileStream - ref return GLOB and fileno is valid</span> | 
|  | 98   85   <span class="c">#   . String - ref return an empty string</span> | 
|  | 99   86   <span class="c">#</span> | 
|  | 100   87   <span class="i">$This</span>->{<span class="w">InputType</span>} = <span class="q">''</span><span class="sc">;</span> | 
|  | 101   88 | 
|  | 102   89   <span class="c"># Tokens specifications supplied by the caller. It's an array containing references</span> | 
|  | 103   90   <span class="c"># to arrays with each containing TokenLabel and TokenMatchRegex pair along with</span> | 
|  | 104   91   <span class="c"># an option reference to code to be executed after a matched.</span> | 
|  | 105   92   <span class="c">#</span> | 
|  | 106   93   <span class="c"># For example:</span> | 
|  | 107   94   <span class="c">#</span> | 
|  | 108   95   <span class="c"># @LexerTokensSpec = (</span> | 
|  | 109   96   <span class="c">#                        [ 'LETTER', qr/[a-zA-Z]/ ],</span> | 
|  | 110   97   <span class="c">#                        [ 'NUMBER', qr/\d+/ ],</span> | 
|  | 111   98   <span class="c">#                        [ 'SPACE', qr/[ ]*/, sub { my($This, $TokenLabel, $MatchedText) = @_; return ''; } ],</span> | 
|  | 112   99   <span class="c">#                        [ 'NEWLINE', qr/(?:\r\n|\r|\n)/, sub { my($This, $TokenLabel, $MatchedText) = @_;  return "\n"; } ],</span> | 
|  | 113  100   <span class="c">#                        [ 'CHAR', qr/[\.]/ ],</span> | 
|  | 114  101   <span class="c">#                       );</span> | 
|  | 115  102   <span class="c">#</span> | 
|  | 116  103   <span class="i">@</span>{<span class="i">$This</span>->{<span class="w">TokensSpec</span>}} = <span class="s">(</span><span class="s">)</span><span class="sc">;</span> | 
|  | 117  104 | 
|  | 118  105   <span class="c"># Refernce to chained lexer...</span> | 
|  | 119  106   <span class="i">$This</span>->{<span class="w">ChainedLexer</span>} = <span class="k">undef</span><span class="sc">;</span> | 
|  | 120  107 | 
|  | 121  108   <span class="k">return</span> <span class="i">$This</span><span class="sc">;</span> | 
|  | 122  109 <span class="s">}</span> | 
|  | 123  110 | 
|  | 124  111 <span class="c"># Validate input parameters and generate a chained lexer...</span> | 
|  | 125  112 <span class="c">#</span> | 
|  | 126 <a name="_ValidateParametersAndGenerateLexer-"></a> 113 <span class="k">sub </span><span class="m">_ValidateParametersAndGenerateLexer</span> <span class="s">{</span> | 
|  | 127  114   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="cm">,</span> <span class="i">$Input</span><span class="cm">,</span> <span class="i">@TokensSpec</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> | 
|  | 128  115 | 
|  | 129  116   <span class="c">#</span> | 
|  | 130  117   <span class="c"># Validate input to be lexed...</span> | 
|  | 131  118   <span class="k">if</span> <span class="s">(</span>!<span class="k">defined</span> <span class="i">$Input</span><span class="s">)</span> <span class="s">{</span> | 
|  | 132  119     <span class="w">croak</span> <span class="q">"Error: ${ClassName}->new: Object can't be instantiated: Input is not defined. Supported values: a reference to input iterator function, a reference to an open file handle or a text string..."</span><span class="sc">;</span> | 
|  | 133  120   <span class="s">}</span> | 
|  | 134  121   <span class="i">$This</span>->{<span class="w">Input</span>} = <span class="i">$Input</span><span class="sc">;</span> | 
|  | 135  122 | 
|  | 136  123   <span class="c"># Check input parameter type...</span> | 
|  | 137  124   <span class="k">my</span><span class="s">(</span><span class="i">$InputType</span><span class="s">)</span><span class="sc">;</span> | 
|  | 138  125 | 
|  | 139  126   <span class="i">$InputType</span> = <span class="k">ref</span> <span class="i">$Input</span><span class="sc">;</span> | 
|  | 140  127   <span class="k">if</span> <span class="s">(</span><span class="i">$InputType</span> =~ <span class="q">/CODE/i</span><span class="s">)</span> <span class="s">{</span> | 
|  | 141  128     <span class="c"># Input iterator...</span> | 
|  | 142  129     <span class="i">$This</span>->{<span class="w">InputType</span>} = <span class="q">"InputIterator"</span><span class="sc">;</span> | 
|  | 143  130   <span class="s">}</span> | 
|  | 144  131   <span class="k">elsif</span> <span class="s">(</span><span class="i">$InputType</span> =~ <span class="q">/GLOB/i</span> && <span class="k">defined</span> <span class="k">fileno</span> <span class="i">$Input</span><span class="s">)</span> <span class="s">{</span> | 
|  | 145  132     <span class="c"># Input stream...</span> | 
|  | 146  133     <span class="i">$This</span>->{<span class="w">InputType</span>} = <span class="q">"FileStream"</span><span class="sc">;</span> | 
|  | 147  134   <span class="s">}</span> | 
|  | 148  135   <span class="k">elsif</span> <span class="s">(</span><span class="i">$InputType</span><span class="s">)</span> <span class="s">{</span> | 
|  | 149  136     <span class="c"># Perl ref function returns nonempty string for all other references...</span> | 
|  | 150  137     <span class="w">croak</span> <span class="q">"Error: ${ClassName}->new: Object can't be instantiated: Invalid input parameter type specified. Supported parameter types: a reference to input iterator function, a reference to an open file handle or a text string..."</span><span class="sc">;</span> | 
|  | 151  138   <span class="s">}</span> | 
|  | 152  139   <span class="k">else</span> <span class="s">{</span> | 
|  | 153  140     <span class="c"># Input string...</span> | 
|  | 154  141     <span class="i">$This</span>->{<span class="w">InputType</span>} = <span class="q">"String"</span><span class="sc">;</span> | 
|  | 155  142   <span class="s">}</span> | 
|  | 156  143 | 
|  | 157  144   <span class="c"># Check tokens specifications...</span> | 
|  | 158  145   <span class="k">if</span> <span class="s">(</span>!<span class="i">@TokensSpec</span><span class="s">)</span> <span class="s">{</span> | 
|  | 159  146     <span class="w">croak</span> <span class="q">"Error: ${ClassName}->new: TokensSpec is not defined or the array doesn't contain any values. Supported values: a reference to an array containg token label, regular expression to match and an option reference to function to modify matched values..."</span><span class="sc">;</span> | 
|  | 160  147   <span class="s">}</span> | 
|  | 161  148   <span class="i">@</span>{<span class="i">$This</span>->{<span class="w">TokensSpec</span>}} = <span class="i">@TokensSpec</span><span class="sc">;</span> | 
|  | 162  149 | 
|  | 163  150   <span class="i">$This</span><span class="i">->_GenerateLexer</span><span class="s">(</span><span class="i">$Input</span><span class="cm">,</span> <span class="i">@TokensSpec</span><span class="s">)</span><span class="sc">;</span> | 
|  | 164  151 | 
|  | 165  152   <span class="k">return</span> <span class="i">$This</span><span class="sc">;</span> | 
|  | 166  153 <span class="s">}</span> | 
|  | 167  154 | 
|  | 168  155 <span class="c"># Generate a lexer using reference to an input iterator function, an open file</span> | 
|  | 169  156 <span class="c"># handle or an input string passed as first parameter by the caller along</span> | 
|  | 170  157 <span class="c"># with token specifications as second paramater...</span> | 
|  | 171  158 <span class="c">#</span> | 
|  | 172 <a name="_GenerateLexer-"></a> 159 <span class="k">sub </span><span class="m">_GenerateLexer</span> <span class="s">{</span> | 
|  | 173  160   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="cm">,</span> <span class="i">$Input</span><span class="cm">,</span> <span class="i">@TokensSpec</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> | 
|  | 174  161 | 
|  | 175  162   <span class="k">if</span> <span class="s">(</span><span class="i">$This</span>->{<span class="w">InputType</span>} =~ <span class="q">/^InputIterator$/i</span><span class="s">)</span> <span class="s">{</span> | 
|  | 176  163     <span class="i">$This</span><span class="i">->_GenerateInputIteratorLexer</span><span class="s">(</span><span class="i">$Input</span><span class="cm">,</span> <span class="i">@TokensSpec</span><span class="s">)</span><span class="sc">;</span> | 
|  | 177  164   <span class="s">}</span> | 
|  | 178  165   <span class="k">elsif</span> <span class="s">(</span><span class="i">$This</span>->{<span class="w">InputType</span>} =~ <span class="q">/^FileStream$/i</span><span class="s">)</span> <span class="s">{</span> | 
|  | 179  166     <span class="i">$This</span><span class="i">->_GenerateInputFileStreamLexer</span><span class="s">(</span><span class="i">$Input</span><span class="cm">,</span> <span class="i">@TokensSpec</span><span class="s">)</span><span class="sc">;</span> | 
|  | 180  167   <span class="s">}</span> | 
|  | 181  168   <span class="k">elsif</span> <span class="s">(</span><span class="i">$This</span>->{<span class="w">InputType</span>} =~ <span class="q">/^String$/i</span><span class="s">)</span> <span class="s">{</span> | 
|  | 182  169     <span class="i">$This</span><span class="i">->_GenerateInputStringLexer</span><span class="s">(</span><span class="i">$Input</span><span class="cm">,</span> <span class="i">@TokensSpec</span><span class="s">)</span><span class="sc">;</span> | 
|  | 183  170   <span class="s">}</span> | 
|  | 184  171   <span class="k">else</span> <span class="s">{</span> | 
|  | 185  172     <span class="w">croak</span> <span class="q">"Error: ${ClassName}->new: Object can't be instantiated: Invalid input parameter type specified. Supported parameter types: a reference to input iterator function, a reference to an open file handle or a text string..."</span><span class="sc">;</span> | 
|  | 186  173   <span class="s">}</span> | 
|  | 187  174 | 
|  | 188  175   <span class="k">return</span> <span class="i">$This</span><span class="sc">;</span> | 
|  | 189  176 <span class="s">}</span> | 
|  | 190  177 | 
|  | 191  178 <span class="c"># Generate a lexer using specifed input iterator...</span> | 
|  | 192  179 <span class="c">#</span> | 
|  | 193 <a name="_GenerateInputIteratorLexer-"></a> 180 <span class="k">sub </span><span class="m">_GenerateInputIteratorLexer</span> <span class="s">{</span> | 
|  | 194  181   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="cm">,</span> <span class="i">$InputIteratorRef</span><span class="cm">,</span> <span class="i">@TokensSpec</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> | 
|  | 195  182 | 
|  | 196  183   <span class="i">$This</span><span class="i">->_GenerateChainedLexer</span><span class="s">(</span><span class="i">$InputIteratorRef</span><span class="cm">,</span> <span class="i">@TokensSpec</span><span class="s">)</span><span class="sc">;</span> | 
|  | 197  184 | 
|  | 198  185   <span class="k">return</span> <span class="i">$This</span><span class="sc">;</span> | 
|  | 199  186 <span class="s">}</span> | 
|  | 200  187 | 
|  | 201  188 <span class="c"># Generate a lexer using specifed input file stream reference...</span> | 
|  | 202  189 <span class="c">#</span> | 
|  | 203 <a name="_GenerateInputFileStreamLexer-"></a> 190 <span class="k">sub </span><span class="m">_GenerateInputFileStreamLexer</span> <span class="s">{</span> | 
|  | 204  191   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="cm">,</span> <span class="i">$FileHandleRef</span><span class="cm">,</span> <span class="i">@TokensSpec</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> | 
|  | 205  192 | 
|  | 206  193   <span class="c"># Iterator is a annoymous function reference and Perl keeps $FileHandleRef</span> | 
|  | 207  194   <span class="c"># in scope during its execution.</span> | 
|  | 208  195 | 
|  | 209  196   <span class="i">$This</span><span class="i">->_GenerateChainedLexer</span><span class="s">(</span> <span class="k">sub</span> <span class="s">{</span> <span class="k">return</span> <span class="q"><$FileHandleRef></span><span class="sc">;</span> <span class="s">}</span><span class="cm">,</span> <span class="i">@TokensSpec</span><span class="s">)</span><span class="sc">;</span> | 
|  | 210  197 | 
|  | 211  198   <span class="k">return</span> <span class="i">$This</span><span class="sc">;</span> | 
|  | 212  199 <span class="s">}</span> | 
|  | 213  200 | 
|  | 214  201 <span class="c"># Generate a lexer using specifed input string...</span> | 
|  | 215  202 <span class="c">#</span> | 
|  | 216 <a name="_GenerateInputStringLexer-"></a> 203 <span class="k">sub </span><span class="m">_GenerateInputStringLexer</span> <span class="s">{</span> | 
|  | 217  204   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="cm">,</span> <span class="i">$Text</span><span class="cm">,</span> <span class="i">@TokensSpec</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> | 
|  | 218  205   <span class="k">my</span><span class="s">(</span><span class="i">@InputText</span><span class="s">)</span> = <span class="s">(</span><span class="i">$Text</span><span class="s">)</span><span class="sc">;</span> | 
|  | 219  206 | 
|  | 220  207   <span class="c"># Iterator is a annoymous function reference and Perl keeps @InputText</span> | 
|  | 221  208   <span class="c"># in scope during its execution.</span> | 
|  | 222  209 | 
|  | 223  210   <span class="i">$This</span><span class="i">->_GenerateChainedLexer</span><span class="s">(</span> <span class="k">sub</span> <span class="s">{</span> <span class="k">return</span> <span class="k">shift</span> <span class="i">@InputText</span><span class="sc">;</span> <span class="s">}</span><span class="cm">,</span> <span class="i">@TokensSpec</span><span class="s">)</span><span class="sc">;</span> | 
|  | 224  211 | 
|  | 225  212   <span class="k">return</span> <span class="i">$This</span><span class="sc">;</span> | 
|  | 226  213 <span class="s">}</span> | 
|  | 227  214 | 
|  | 228  215 <span class="c"># Get next available token label and value pair as an array reference or unrecognized</span> | 
|  | 229  216 <span class="c"># text from input stream by either removing it from the input or simply peeking ahead...</span> | 
|  | 230  217 <span class="c">#</span> | 
|  | 231  218 <span class="c"># Supported mode values: Peek, Next. Default: Next</span> | 
|  | 232  219 <span class="c">#</span> | 
|  | 233 <a name="Lex-"></a> 220 <span class="k">sub </span><span class="m">Lex</span> <span class="s">{</span> | 
|  | 234  221   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="cm">,</span> <span class="i">$Mode</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> | 
|  | 235  222 | 
|  | 236  223   <span class="k">return</span> <span class="i">$This</span>->{<span class="w">ChainedLexer</span>}-><span class="s">(</span><span class="i">$Mode</span><span class="s">)</span> | 
|  | 237  224 <span class="s">}</span> | 
|  | 238  225 | 
|  | 239  226 <span class="c"># Get next available token label and value pair as an array reference or unrecognized</span> | 
|  | 240  227 <span class="c"># text from input stream by either removing it from the input stream...</span> | 
|  | 241  228 <span class="c">#</span> | 
|  | 242 <a name="Next-"></a> 229 <span class="k">sub </span><span class="m">Next</span> <span class="s">{</span> | 
|  | 243  230   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> | 
|  | 244  231 | 
|  | 245  232   <span class="k">return</span> <span class="i">$This</span><span class="i">->Lex</span><span class="s">(</span><span class="s">)</span><span class="sc">;</span> | 
|  | 246  233 <span class="s">}</span> | 
|  | 247  234 | 
|  | 248  235 <span class="c"># Get next available token label and value pair as an array reference or unrecognized</span> | 
|  | 249  236 <span class="c"># text from input stream by simply peeking ahead and without removing it from the input</span> | 
|  | 250  237 <span class="c"># stream..</span> | 
|  | 251  238 <span class="c">#</span> | 
|  | 252 <a name="Peek-"></a> 239 <span class="k">sub </span><span class="m">Peek</span> <span class="s">{</span> | 
|  | 253  240   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> | 
|  | 254  241 | 
|  | 255  242   <span class="k">return</span> <span class="i">$This</span><span class="i">->Lex</span><span class="s">(</span><span class="q">'Peek'</span><span class="s">)</span> | 
|  | 256  243 <span class="s">}</span> | 
|  | 257  244 | 
|  | 258  245 <span class="c"># Get a reference to lexer method to be used by the caller...</span> | 
|  | 259  246 <span class="c">#</span> | 
|  | 260 <a name="GetLex-"></a> 247 <span class="k">sub </span><span class="m">GetLex</span> <span class="s">{</span> | 
|  | 261  248   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> | 
|  | 262  249 | 
|  | 263  250   <span class="k">return</span> <span class="k">sub</span> <span class="s">{</span> <span class="i">$This</span><span class="i">->Lex</span><span class="s">(</span><span class="s">)</span><span class="sc">;</span> <span class="s">}</span><span class="sc">;</span> | 
|  | 264  251 <span class="s">}</span> | 
|  | 265  252 | 
|  | 266  253 <span class="c"># The chained lexer generation is implemented based on examples in Higher-order Perl</span> | 
|  | 267  254 <span class="c"># [ Ref 126 ] book.</span> | 
|  | 268  255 <span class="c">#</span> | 
|  | 269  256 <span class="c"># Generate a lexer using specified input iterator and chaining it with other lexers generated</span> | 
|  | 270  257 <span class="c"># for all token specifications. The lexer generated for first token specification uses input</span> | 
|  | 271  258 <span class="c"># iterator to retrieve any available input text; the subsequent chained lexeres for rest</span> | 
|  | 272  259 <span class="c"># of the tokens use lexers generated for previous token specifications to get next input</span> | 
|  | 273  260 <span class="c"># which might be unmatched input text or a reference to an array containing token and</span> | 
|  | 274  261 <span class="c"># matched text pair.</span> | 
|  | 275  262 <span class="c">#</span> | 
|  | 276 <a name="_GenerateChainedLexer-"></a> 263 <span class="k">sub </span><span class="m">_GenerateChainedLexer</span> <span class="s">{</span> | 
|  | 277  264   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="cm">,</span> <span class="i">$InputIteratorRef</span><span class="cm">,</span> <span class="i">@TokensSpec</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> | 
|  | 278  265   <span class="k">my</span><span class="s">(</span><span class="i">$TokenSpecRef</span><span class="cm">,</span> <span class="i">$ChainedLexer</span><span class="s">)</span><span class="sc">;</span> | 
|  | 279  266 | 
|  | 280  267   <span class="i">$ChainedLexer</span> = <span class="k">undef</span><span class="sc">;</span> | 
|  | 281  268   <span class="k">for</span> <span class="i">$TokenSpecRef</span> <span class="s">(</span><span class="i">@TokensSpec</span><span class="s">)</span> <span class="s">{</span> | 
|  | 282  269     <span class="i">$ChainedLexer</span> = <span class="k">defined</span> <span class="i">$ChainedLexer</span> ? <span class="i">$This</span><span class="i">->_GenerateLexerForToken</span><span class="s">(</span><span class="i">$ChainedLexer</span><span class="cm">,</span> <span class="i">@</span>{<span class="i">$TokenSpecRef</span>}<span class="s">)</span> <span class="co">:</span> <span class="i">$This</span><span class="i">->_GenerateLexerForToken</span><span class="s">(</span><span class="i">$InputIteratorRef</span><span class="cm">,</span> <span class="i">@</span>{<span class="i">$TokenSpecRef</span>}<span class="s">)</span><span class="sc">;</span> | 
|  | 283  270   <span class="s">}</span> | 
|  | 284  271 | 
|  | 285  272   <span class="i">$This</span>->{<span class="w">ChainedLexer</span>} = <span class="i">$ChainedLexer</span><span class="sc">;</span> | 
|  | 286  273 | 
|  | 287  274   <span class="k">return</span> <span class="i">$This</span><span class="sc">;</span> | 
|  | 288  275 <span class="s">}</span> | 
|  | 289  276 | 
|  | 290  277 | 
|  | 291  278 <span class="c"># Generate a lexer using specifed token specification using specified input or</span> | 
|  | 292  279 <span class="c"># input retrieved using another token lexer. The lexer retrieving input from the</span> | 
|  | 293  280 <span class="c"># specified input stream is at the bottom of the chain.</span> | 
|  | 294  281 <span class="c">#</span> | 
|  | 295 <a name="_GenerateLexerForToken-"></a> 282 <span class="k">sub </span><span class="m">_GenerateLexerForToken</span> <span class="s">{</span> | 
|  | 296  283   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="cm">,</span> <span class="i">$InputIteratorOrLexer</span><span class="cm">,</span> <span class="i">$TokenLabel</span><span class="cm">,</span> <span class="i">$RegexPattern</span><span class="cm">,</span> <span class="i">$TokenMatchActionRef</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> | 
|  | 297  284   <span class="k">my</span><span class="s">(</span><span class="i">$TokenMatchAndSplitRef</span><span class="cm">,</span> <span class="i">$InputBuffer</span><span class="cm">,</span> <span class="i">@ProcessedTokens</span><span class="s">)</span><span class="sc">;</span> | 
|  | 298  285 | 
|  | 299  286   <span class="c"># Input buffer for a specific lexer in chained lexers containing unprocessed</span> | 
|  | 300  287   <span class="c"># text for token specifications retrieved from a downstrean lexer or intial</span> | 
|  | 301  288   <span class="c"># input...</span> | 
|  | 302  289   <span class="c">#</span> | 
|  | 303  290   <span class="i">$InputBuffer</span> = <span class="q">""</span><span class="sc">;</span> | 
|  | 304  291 | 
|  | 305  292   <span class="c"># @ProcessedTokens contains either references to an array containing token label</span> | 
|  | 306  293   <span class="c"># and matched text or any unmatched input text string...</span> | 
|  | 307  294   <span class="c">#</span> | 
|  | 308  295   <span class="i">@ProcessedTokens</span> = <span class="s">(</span><span class="s">)</span><span class="sc">;</span> | 
|  | 309  296 | 
|  | 310  297   <span class="c"># Setup a default annoymous function reference to generate an array reference</span> | 
|  | 311  298   <span class="c"># containing $Token and text matched to $RegexPattern.</span> | 
|  | 312  299   <span class="c">#</span> | 
|  | 313  300   <span class="i">$TokenMatchActionRef</span> = <span class="k">defined</span> <span class="i">$TokenMatchActionRef</span> ? <span class="i">$TokenMatchActionRef</span> <span class="co">:</span> <span class="k">sub</span> <span class="s">{</span> <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="cm">,</span> <span class="i">$Label</span><span class="cm">,</span> <span class="i">$MatchedText</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> <span class="k">return</span> <span class="s">[</span><span class="i">$Label</span><span class="cm">,</span> <span class="i">$MatchedText</span><span class="s">]</span>  <span class="s">}</span><span class="sc">;</span> | 
|  | 314  301 | 
|  | 315  302   <span class="c"># Setup an annoymous function to match and split input text using $RegexPattern for</span> | 
|  | 316  303   <span class="c"># a specific token during its lexer invocation in chained lexers.</span> | 
|  | 317  304   <span class="c">#</span> | 
|  | 318  305   <span class="c"># The usage of parenthesis around $RegexPattern during split allows capturing of matched</span> | 
|  | 319  306   <span class="c"># text, which is subsequently processed to retrieve matched $Token values. The split function</span> | 
|  | 320  307   <span class="c"># inserts a "" separator in the returned array as first entry whenever $InputText starts with</span> | 
|  | 321  308   <span class="c"># $RegexPattern. $InputText is returned as the only element for no match.</span> | 
|  | 322  309   <span class="c">#</span> | 
|  | 323  310   <span class="i">$TokenMatchAndSplitRef</span> = <span class="k">sub</span> <span class="s">{</span> <span class="k">my</span><span class="s">(</span><span class="i">$InputText</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> <span class="k">return</span> <span class="k">split</span> <span class="q">/($RegexPattern)/</span><span class="cm">,</span> <span class="i">$InputText</span><span class="sc">;</span> <span class="s">}</span><span class="sc">;</span> | 
|  | 324  311 | 
|  | 325  312   <span class="c"># Setup a lexer for $TokenLabel as an annoymous function and return its reference to caller</span> | 
|  | 326  313   <span class="c"># which in turns chains the lexers for all $Tokens before returning a reference to a lexer</span> | 
|  | 327  314   <span class="c"># at top of the lexer chain.</span> | 
|  | 328  315   <span class="c">#</span> | 
|  | 329  316   <span class="c"># Perl maintains scope of all variables defined with in the scope of the current function</span> | 
|  | 330  317   <span class="c"># during invocation of annoymous function even after the return call.</span> | 
|  | 331  318   <span class="c">#</span> | 
|  | 332  319   <span class="k">return</span> <span class="k">sub</span> <span class="s">{</span> | 
|  | 333  320     <span class="k">my</span><span class="s">(</span><span class="i">$Mode</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> | 
|  | 334  321 | 
|  | 335  322     <span class="c"># Currenly supported value for mode: Peek, Next</span> | 
|  | 336  323     <span class="c">#</span> | 
|  | 337  324     <span class="i">$Mode</span> = <span class="k">defined</span> <span class="i">$Mode</span> ? <span class="i">$Mode</span> <span class="co">:</span> <span class="q">'Next'</span><span class="sc">;</span> | 
|  | 338  325 | 
|  | 339  326     <span class="k">while</span> <span class="s">(</span><span class="i">@ProcessedTokens</span> == <span class="n">0</span> && <span class="k">defined</span> <span class="i">$InputBuffer</span> <span class="s">)</span> <span class="s">{</span> | 
|  | 340  327       <span class="c"># Get any new input....</span> | 
|  | 341  328       <span class="k">my</span> <span class="i">$NewInput</span> = <span class="i">$InputIteratorOrLexer</span>-><span class="s">(</span><span class="s">)</span><span class="sc">;</span> | 
|  | 342  329 | 
|  | 343  330       <span class="k">if</span> <span class="s">(</span><span class="k">ref</span> <span class="i">$NewInput</span><span class="s">)</span> <span class="s">{</span> | 
|  | 344  331         <span class="c"># Input is an array reference containing matched token and text returned by</span> | 
|  | 345  332         <span class="c"># a chained lexer downstream lexer...</span> | 
|  | 346  333         <span class="c">#</span> | 
|  | 347  334         <span class="c"># Match $RegexPattern in available buffer text to retieve any matched text</span> | 
|  | 348  335         <span class="c"># for current $Token. $Separator might be "": $RegexPattern is at start of</span> | 
|  | 349  336         <span class="c"># of $InputBuffer</span> | 
|  | 350  337         <span class="c">#</span> | 
|  | 351  338         <span class="c"># Process input buffer containing text to be matched for the current lexer</span> | 
|  | 352  339         <span class="c"># which didn't get processed earlier during @NewTokens > 2  while loop:</span> | 
|  | 353  340         <span class="c"># no match for current lexer or more input available. It maintains order</span> | 
|  | 354  341         <span class="c"># of token matching in input stream.</span> | 
|  | 355  342         <span class="c">#</span> | 
|  | 356  343         <span class="k">my</span><span class="s">(</span><span class="i">$Separator</span><span class="cm">,</span> <span class="i">$MatchedTokenRefOrText</span><span class="s">)</span><span class="sc">;</span> | 
|  | 357  344 | 
|  | 358  345         <span class="s">(</span><span class="i">$Separator</span><span class="cm">,</span> <span class="i">$MatchedTokenRefOrText</span><span class="s">)</span> = <span class="i">$TokenMatchAndSplitRef</span>-><span class="s">(</span><span class="i">$InputBuffer</span><span class="s">)</span><span class="sc">;</span> | 
|  | 359  346         <span class="k">if</span> <span class="s">(</span><span class="k">defined</span> <span class="i">$MatchedTokenRefOrText</span><span class="s">)</span> <span class="s">{</span> | 
|  | 360  347           <span class="i">$MatchedTokenRefOrText</span> = <span class="i">$TokenMatchActionRef</span>-><span class="s">(</span><span class="i">$This</span><span class="cm">,</span> <span class="i">$TokenLabel</span><span class="cm">,</span> <span class="i">$MatchedTokenRefOrText</span><span class="s">)</span><span class="sc">;</span> | 
|  | 361  348         <span class="s">}</span> | 
|  | 362  349 | 
|  | 363  350         <span class="c"># Collect valid token references or text...</span> | 
|  | 364  351         <span class="k">push</span> <span class="i">@ProcessedTokens</span><span class="cm">,</span> <span class="k">grep</span> <span class="s">{</span> <span class="k">defined</span> <span class="i">$_</span> && <span class="i">$_</span> <span class="k">ne</span> <span class="q">""</span> <span class="s">}</span> <span class="s">(</span><span class="i">$Separator</span><span class="cm">,</span> <span class="i">$MatchedTokenRefOrText</span><span class="cm">,</span> <span class="i">$NewInput</span><span class="s">)</span><span class="sc">;</span> | 
|  | 365  352 | 
|  | 366  353         <span class="c"># Empty put buffer...</span> | 
|  | 367  354         <span class="i">$InputBuffer</span> = <span class="q">""</span><span class="sc">;</span> | 
|  | 368  355 | 
|  | 369  356         <span class="c"># Get out of the loop as processed token refererences and/or text  are available...</span> | 
|  | 370  357         <span class="k">last</span><span class="sc">;</span> | 
|  | 371  358       <span class="s">}</span> | 
|  | 372  359 | 
|  | 373  360       <span class="c"># Process input retrieved from downstream lexer or input iterator which hasn't</span> | 
|  | 374  361       <span class="c"># been processed into tokens..</span> | 
|  | 375  362       <span class="k">if</span> <span class="s">(</span><span class="k">defined</span> <span class="i">$NewInput</span><span class="s">)</span> <span class="s">{</span> | 
|  | 376  363         <span class="i">$InputBuffer</span> .= <span class="i">$NewInput</span><span class="sc">;</span> | 
|  | 377  364       <span class="s">}</span> | 
|  | 378  365 | 
|  | 379  366       <span class="c"># Retrieve any matched tokens from available input for the current lexer...</span> | 
|  | 380  367       <span class="c">#</span> | 
|  | 381  368       <span class="k">my</span><span class="s">(</span><span class="i">@NewTokens</span><span class="s">)</span> = <span class="i">$TokenMatchAndSplitRef</span>-><span class="s">(</span><span class="i">$InputBuffer</span><span class="s">)</span><span class="sc">;</span> | 
|  | 382  369 | 
|  | 383  370       <span class="k">while</span> <span class="s">(</span> <span class="i">@NewTokens</span> > <span class="n">2</span> || <span class="i">@NewTokens</span> && !<span class="k">defined</span> <span class="i">$NewInput</span><span class="s">)</span> <span class="s">{</span> | 
|  | 384  371         <span class="c"># Scenario 1: Complete match</span> | 
|  | 385  372         <span class="c">#   @NewTokens > 2 : Availability of separator, matched token text, separator.</span> | 
|  | 386  373         <span class="c">#   The separator might correspond to token for a token for upstream lexer followed</span> | 
|  | 387  374         <span class="c">#   by matched token from current lexer. It ends up getting passed to upsrteam</span> | 
|  | 388  375         <span class="c">#   lexer for processing.</span> | 
|  | 389  376         <span class="c">#</span> | 
|  | 390  377         <span class="c"># Scenario 2: No more input available from iterator or downstream lexer</span> | 
|  | 391  378         <span class="c">#   @NewTokens <= 2 and no more input implies any left over text in buffer. And</span> | 
|  | 392  379         <span class="c">#   it ends up getting passed to upsrteam for processing.</span> | 
|  | 393  380         <span class="c">#</span> | 
|  | 394  381 | 
|  | 395  382         <span class="c"># Take off any unprocessed input text that doesn't match off the buffer: It'll be</span> | 
|  | 396  383         <span class="c"># passed to upstream chained lexer for processing...</span> | 
|  | 397  384         <span class="c">#</span> | 
|  | 398  385         <span class="k">push</span> <span class="i">@ProcessedTokens</span><span class="cm">,</span> <span class="k">shift</span> <span class="i">@NewTokens</span><span class="sc">;</span> | 
|  | 399  386 | 
|  | 400  387         <span class="k">if</span> <span class="s">(</span><span class="i">@NewTokens</span><span class="s">)</span> <span class="s">{</span> | 
|  | 401  388           <span class="k">my</span> <span class="i">$MatchedTokenText</span> = <span class="k">shift</span> <span class="i">@NewTokens</span><span class="sc">;</span> | 
|  | 402  389           <span class="k">push</span> <span class="i">@ProcessedTokens</span><span class="cm">,</span> <span class="i">$TokenMatchActionRef</span>-><span class="s">(</span><span class="i">$This</span><span class="cm">,</span> <span class="i">$TokenLabel</span><span class="cm">,</span> <span class="i">$MatchedTokenText</span><span class="s">)</span><span class="sc">;</span> | 
|  | 403  390         <span class="s">}</span> | 
|  | 404  391       <span class="s">}</span> | 
|  | 405  392 | 
|  | 406  393       <span class="c"># Retrieve any leftover text from NewTokens and put it back into InputBuffer for</span> | 
|  | 407  394       <span class="c"># processing by current lexer. All token references have been taken out....</span> | 
|  | 408  395       <span class="c">#</span> | 
|  | 409  396       <span class="i">$InputBuffer</span> = <span class="q">""</span><span class="sc">;</span> | 
|  | 410  397       <span class="k">if</span> <span class="s">(</span><span class="i">@NewTokens</span><span class="s">)</span> <span class="s">{</span> | 
|  | 411  398         <span class="i">$InputBuffer</span> = <span class="k">join</span> <span class="q">""</span><span class="cm">,</span> <span class="i">@NewTokens</span><span class="sc">;</span> | 
|  | 412  399       <span class="s">}</span> | 
|  | 413  400 | 
|  | 414  401       <span class="k">if</span> <span class="s">(</span>!<span class="k">defined</span> <span class="i">$NewInput</span><span class="s">)</span> <span class="s">{</span> | 
|  | 415  402         <span class="c"># No more input from the downstream lexer...</span> | 
|  | 416  403         <span class="i">$InputBuffer</span> = <span class="k">undef</span><span class="sc">;</span> | 
|  | 417  404       <span class="s">}</span> | 
|  | 418  405 | 
|  | 419  406       <span class="c"># Clean up any empty strings from ProcessedTokens containing token</span> | 
|  | 420  407       <span class="c"># references or text...</span> | 
|  | 421  408       <span class="i">@ProcessedTokens</span> = <span class="k">grep</span> <span class="s">{</span> <span class="i">$_</span> <span class="k">ne</span> <span class="q">""</span> <span class="s">}</span> <span class="i">@ProcessedTokens</span><span class="sc">;</span> | 
|  | 422  409 | 
|  | 423  410     <span class="s">}</span> | 
|  | 424  411 | 
|  | 425  412     <span class="c"># Return reference to an array containing token and matched text or just unmatched input text...</span> | 
|  | 426  413     <span class="k">my</span> <span class="i">$TokenRefOrText</span> = <span class="k">undef</span><span class="sc">;</span> | 
|  | 427  414 | 
|  | 428  415     <span class="k">if</span> <span class="s">(</span><span class="i">@ProcessedTokens</span><span class="s">)</span> <span class="s">{</span> | 
|  | 429  416       <span class="c"># Get first available reference either by just peeking or removing it from the list</span> | 
|  | 430  417       <span class="c"># of available tokens...</span> | 
|  | 431  418       <span class="i">$TokenRefOrText</span> = <span class="s">(</span><span class="i">$Mode</span> =~ <span class="q">/^Peek$/i</span><span class="s">)</span> ?  <span class="i">$ProcessedTokens</span>[<span class="n">0</span>] <span class="co">:</span> <span class="k">shift</span> <span class="i">@ProcessedTokens</span><span class="sc">;</span> | 
|  | 432  419     <span class="s">}</span> | 
|  | 433  420 | 
|  | 434  421     <span class="k">return</span> <span class="i">$TokenRefOrText</span><span class="sc">;</span> | 
|  | 435  422   <span class="s">}</span><span class="sc">;</span> | 
|  | 436  423 <span class="s">}</span> | 
|  | 437  424 | 
|  | 438  425 <span class="c"># Is it a lexer object?</span> | 
|  | 439 <a name="_IsLexer-"></a> 426 <span class="k">sub </span><span class="m">_IsLexer</span> <span class="s">{</span> | 
|  | 440  427   <span class="k">my</span><span class="s">(</span><span class="i">$Object</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> | 
|  | 441  428 | 
|  | 442  429   <span class="k">return</span> <span class="s">(</span><span class="i">Scalar::Util::blessed</span><span class="s">(</span><span class="i">$Object</span><span class="s">)</span> && <span class="i">$Object</span><span class="i">->isa</span><span class="s">(</span><span class="i">$ClassName</span><span class="s">)</span><span class="s">)</span> ? <span class="n">1</span> <span class="co">:</span> <span class="n">0</span><span class="sc">;</span> | 
|  | 443  430 <span class="s">}</span> | 
|  | 444  431 | 
|  | 445  432 <span class="c"># Return a string containing information about lexer...</span> | 
|  | 446 <a name="StringifyLexer-"></a> 433 <span class="k">sub </span><span class="m">StringifyLexer</span> <span class="s">{</span> | 
|  | 447  434   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> | 
|  | 448  435   <span class="k">my</span><span class="s">(</span><span class="i">$LexerString</span><span class="s">)</span><span class="sc">;</span> | 
|  | 449  436 | 
|  | 450  437   <span class="i">$LexerString</span> = <span class="q">"Lexer: PackageName: $ClassName; "</span> . <span class="i">$This</span><span class="i">->_GetLexerInfoString</span><span class="s">(</span><span class="s">)</span><span class="sc">;</span> | 
|  | 451  438 | 
|  | 452  439   <span class="k">return</span> <span class="i">$LexerString</span><span class="sc">;</span> | 
|  | 453  440 <span class="s">}</span> | 
|  | 454  441 | 
|  | 455  442 <span class="c"># Return a string containing information about lexer...</span> | 
|  | 456 <a name="_GetLexerInfoString-"></a> 443 <span class="k">sub </span><span class="m">_GetLexerInfoString</span> <span class="s">{</span> | 
|  | 457  444   <span class="k">my</span><span class="s">(</span><span class="i">$This</span><span class="s">)</span> = <span class="i">@_</span><span class="sc">;</span> | 
|  | 458  445   <span class="k">my</span><span class="s">(</span><span class="i">$LexerInfoString</span><span class="cm">,</span> <span class="i">$TokensSpec</span><span class="cm">,</span> <span class="i">$TokenSpec</span><span class="cm">,</span> <span class="i">$TokenLabel</span><span class="cm">,</span> <span class="i">$TokenMatchRegex</span><span class="cm">,</span> <span class="i">$TokenMatchAction</span><span class="s">)</span><span class="sc">;</span> | 
|  | 459  446 | 
|  | 460  447   <span class="i">$LexerInfoString</span> = <span class="q">"InputType: $This->{InputType}"</span><span class="sc">;</span> | 
|  | 461  448 | 
|  | 462  449   <span class="k">if</span> <span class="s">(</span><span class="i">$This</span>->{<span class="w">InputType</span>} =~ <span class="q">/^String$/i</span><span class="s">)</span> <span class="s">{</span> | 
|  | 463  450     <span class="i">$LexerInfoString</span> .= <span class="q">"; InputString: $This->{Input}"</span><span class="sc">;</span> | 
|  | 464  451   <span class="s">}</span> | 
|  | 465  452 | 
|  | 466  453   <span class="i">$TokensSpec</span> = <span class="q">"TokensSpecifications: <None>"</span><span class="sc">;</span> | 
|  | 467  454   <span class="k">if</span> <span class="s">(</span><span class="i">@</span>{<span class="i">$This</span>->{<span class="w">TokensSpec</span>}}<span class="s">)</span> <span class="s">{</span> | 
|  | 468  455     <span class="i">$TokensSpec</span> = <span class="q">"TokensSpecifications: < [Label, MatchRegex, MatchAction]:"</span><span class="sc">;</span> | 
|  | 469  456     <span class="k">for</span> <span class="i">$TokenSpec</span> <span class="s">(</span><span class="i">@</span>{<span class="i">$This</span>->{<span class="w">TokensSpec</span>}}<span class="s">)</span> <span class="s">{</span> | 
|  | 470  457       <span class="s">(</span><span class="i">$TokenLabel</span><span class="cm">,</span> <span class="i">$TokenMatchRegex</span><span class="s">)</span> = <span class="i">@</span>{<span class="i">$TokenSpec</span>}<span class="sc">;</span> | 
|  | 471  458       <span class="i">$TokenMatchAction</span> = <span class="s">(</span><span class="i">@</span>{<span class="i">$TokenSpec</span>} == <span class="n">3</span><span class="s">)</span> ? <span class="q">"$TokenSpec->[2]"</span> <span class="co">:</span> <span class="q">"undefined"</span><span class="sc">;</span> | 
|  | 472  459       <span class="i">$TokensSpec</span> .= <span class="q">" [$TokenLabel, $TokenMatchRegex, $TokenMatchAction]"</span><span class="sc">;</span> | 
|  | 473  460     <span class="s">}</span> | 
|  | 474  461     <span class="i">$TokensSpec</span> .= <span class="q">" >"</span><span class="sc">;</span> | 
|  | 475  462   <span class="s">}</span> | 
|  | 476  463 | 
|  | 477  464   <span class="i">$LexerInfoString</span> .= <span class="q">"; $TokensSpec"</span><span class="sc">;</span> | 
|  | 478  465 | 
|  | 479  466   <span class="k">return</span> <span class="i">$LexerInfoString</span><span class="sc">;</span> | 
|  | 480  467 <span class="s">}</span> | 
|  | 481  468 | 
|  | 482 <a name="EOF-"></a></pre> | 
|  | 483 <p> </p> | 
|  | 484 <br /> | 
|  | 485 <center> | 
|  | 486 <img src="../../../images/h2o2.png"> | 
|  | 487 </center> | 
|  | 488 </body> | 
|  | 489 </html> |