anchor.diff:    ;
   //[4]
   ForExpr
  -  : SimpleForClause "return" ExprSingle
  +  : SimpleForClause 'return' ExprSingle
     ;
   //[5]
   SimpleForClause
  -  : "for" "$" VarName "in" ExprSingle ("," "$" VarName "in" ExprSingle)*
  +  : 'for' '$' VarName 'in' ExprSingle (',' '$' VarName 'in' ExprSingle)*
     ;
   //[6]
   QuantifiedExpr
  -  : ("some" | "every") "$" VarName "in" ExprSingle ("," "$" VarName "in" ExprSingle)* "satisfies" ExprSingle
  +  : ('some' | 'every') '$' VarName 'in' ExprSingle (',' '$' VarName 'in' ExprSingle)* 'satisfies' ExprSingle
     ;
   //[7]
   IfExpr
  -  : "if" "(" Expr ")" "then" ExprSingle "else" ExprSingle
  +  : 'if' '(' Expr ')' 'then' ExprSingle 'else' ExprSingle
     ;
   //[8]
   OrExpr
  -  : AndExpr ( "or" AndExpr )*
  +  : AndExpr ( 'or' AndExpr )*
     ;
   //[9]
   AndExpr
  -  : ComparisonExpr ( "and" ComparisonExpr )*
  +  : ComparisonExpr ( 'and' ComparisonExpr )*
     ;
   //[10]
   ComparisonExpr
  
positive.code: fragment
  Char
    : '\u0009'           | '\u000A'           | '\u000D' 
    | '\u0020'..'\uD7FF' | '\uE000'..'\uFFFD' | '\u10000'..'\u10FFFF'
    ;   
negative.code:   ;
  //[40]
  Predicate
    : '[' Expr ']'
    ;
  //[41]
  PrimaryExpr
  