/*

  Specification of disambiguation for parsing currently requires direct use of
  the corresponding SDF3 notation in comments, along with embedded productions
  in CBS notation. The well-formedness of the SDF3 notation is not checked.
  A future version of CBS is to include appropriate constructs for specifying
  disambiguation.

/*

context-free syntax

``expr ::= expr '+' expr``          {left}
``expr ::= expr '/' expr``          {left}
``expr ::= expr '*' expr``          {left}
``expr ::= expr '-' expr``          {left}
``expr ::= expr '==' expr``         {non-assoc}
``expr ::= expr '<=' expr``         {non-assoc}
``expr ::= expr '<' expr``          {non-assoc}
``expr ::= expr '!=' expr``         {non-assoc}
``expr ::= expr '>=' expr``         {non-assoc}
``expr ::= expr '>' expr``          {non-assoc}
``expr ::= expr '&&' expr``         {left}
``expr ::= expr '||' expr``         {left}
``expr ::= id '=' expr``            {right}
``expr ::= expr '.' id '=' expr``   {right}

context-free priorities

  {left: 
    ``expr ::= expr '.' id '(' expr-list? ')'``  
  }
  > 
  {right: 
    ``expr ::= '!' expr``
  }
  > 
  {left: 
    ``expr ::= expr '*'  expr``
    ``expr ::= expr '&&' expr``
  }
  > 
  {non-assoc: 
    ``expr ::= expr '==' expr``
    ``expr ::= expr '<=' expr``
    ``expr ::= expr '<'  expr``
    ``expr ::= expr '!=' expr``
    ``expr ::= expr '>=' expr``
    ``expr ::= expr '>'  expr``
  }
  > 
  {left: 
    ``expr ::= expr '+'  expr``
    ``expr ::= expr '-'  expr``
    ``expr ::= expr '||' expr``
  }
  > 
  {right: 
    ``expr ::= id '=' expr``
    ``expr ::= expr '.' id '=' expr``
  }

/*

lexical syntax
``id`` = "function" {reject}
``id`` = "true"     {reject}
``id`` = "false"    {reject}
``id`` = "return"   {reject}
``id`` = "break"    {reject}
``id`` = "continue" {reject}
``id`` = "while"    {reject}
``id`` = "if"       {reject}
``id`` = "else"     {reject}

lexical restrictions
// Ensure greedy matching for lexicals
``nat`` -/- [0-9]
``id``  -/- [a-zA-Z0-9\_]