Experimental lexer generator: Lex files with zeros properly.

tools/lexer_generator/code_generator.jinja

 #include "lexer/even-more-experimental-scanner.h"
 
 
 {# TODO implement CLASS checks #}
 {%- macro do_key(key) -%}
   {%- for r in key.range_iter() -%}
     {%- if not loop.first %} || {% endif -%}
     {%- if r[0] == 'LATIN_1' -%}
       {%- if r[1][0] == r[1][1] -%}
         yych == {{r[1][0]}}
       {%- elif r[1][0] == 0 -%}
         yych <= {{r[1][1]}}
       {%- elif r[1][1] == 255 -%}
         yych >= {{r[1][0]}}
       {%- else -%}
         ({{r[1][0]}} <= yych && yych <= {{r[1][1]}})
       {%- endif -%}
+    {%- elif r[0] == 'CLASS' -%}
+      {%- if r[1] == 'eof' -%}
+        (yych == 0 && cursor_ == buffer_end_)
+      {%- else -%}
+        false
+      {%- endif -%}
     {%- else -%}
       false
     {%- endif -%}
   {%- endfor -%}
 {%- endmacro -%}
 
 
 {% macro dispatch_action(type, value) -%}
   {%- if type == 'code' %}
     {{value}}
@@ skipping 120 matching lines @@
 {% endif -%}
     {{dispatch_action(default_action[0], default_action[1])}}
   FORWARD();
   goto code_start;
 
   fell_through:
   CHECK(false);
 }
 } }