anchor.diff:      ;
   
   function_call
  -    : scalar_function_name '(' expression_list? ')'
  +    : ranking_windowed_function
  +    | aggregate_windowed_function
  +    | scalar_function_name '(' expression_list? ')'
       // https://msdn.microsoft.com/en-us/library/ms173784.aspx
       | BINARY_CHECKSUM '(' '*' ')'
       // https://msdn.microsoft.com/en-us/library/hh231076.aspx
  
positive.code: The MIT License (MIT).
  Copyright (c) 2015-2016, Ivan Kochurkin (kvanttt@gmail.com), Positive Technologies.
  Copyright (c) 2016, Scott Ure (scott@redstormsoftware.com).
  
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  
negative.code:     | op=('+' | '-') expression                                #unary_operator_expression
      | expression op=('+' | '-' | '&' | '^' | '|') expression   #binary_operator_expression
      | expression comparison_operator expression                #binary_operator_expression
      ;
  
  constant_expression
  