anchor.diff:  KW_CONST: 'const';
   KW_INSTANCEOF: 'instanceof';
   KW_NEW: 'new';
  +
  +PHP_START: '<?php' ;
  +PHP_END: '?>' ;
   
   ID:
     ('a'..'z'|'A'..'Z'|'_'|'\u007f'..'\u00ff') ('a'..'z'|'A'..'Z'|'0'..'9'|'_'|'\u007f'..'\u00ff')*
  
positive.code:   | KW_TRUE
    | KW_FALSE
    | variable_or_call_list
    ;
  
  variable_or_call_list
  
negative.code:   ;
  
  expr_assign
    : (indexed_variable assign_op) =>
       indexed_variable assign_op expr_assign
        -> ^(assign_op indexed_variable expr_assign)
    | logical_or
    ;
  
  assign_op
    : EQ
    | PLUS_EQ
    | MINUS_EQ
    | MUL_EQ
    | DIV_EQ
    | DOT_EQ
    | MOD_EQ
    | AND_EQ
    | OR_EQ
    | XOR_EQ
    | SHL_EQ
    | SHR_EQ
    ;
  
  logical_or
  