anchor.diff:  
   The number of values in a READ statement do not have to match the number of values in DATA statements.
   The values defined in DATA statements are stored in a single list of use by all READ statements.
  -You may READ in pairs and define ten values per DATA statement. You may READ ten items from DATA statements that contain one value each.
  +You may READ in pairs and define ten values per DATA statement.
  +You may READ ten items from DATA statements that contain one value each.
   
   READing more values than are specified by DATA statements, in total, will cause an error.
   
  -BASIC keeps an internal pointer to the next data item. This pointer can be reset with the RESTORE statement.
  +BASIC keeps an internal pointer to the next data item.
  +This pointer can be reset with the RESTORE statement.
   
   Reading from files
   ^^^^^^^^^^^^^^^^^^
  
positive.code: Immediate commands
  ------------------
  
  Immediate commands are executed on the command line. They are not stored as part of the program. They have no line number. They are available only in "run" mode.
  
  NEW
  ~~~
  
negative.code: 
  BASIC-1973 keeps the spirit of the original BASIC language, as much as possible.
  Everything must be in upper case, except for text constants in PRINT statements.
  Commands ("RUN", "LIST"), statements ("PRINT", "LET"), function names, and variable names must be in upper case.
  Lower case causes an error.
  
  
  Keywords and tokens
  