Boolean Expressions

peg.grammar

Start
  = _* node:Node+
    {
        return node[0];
    }
  / _*
    {
        return {};
    }
  / EOF
    {
        return {};
    }

Node
  = operator:Op_Expr EOF
    {
        return { operator };
    }
  / operator:Op_Expr right:Node
    {
        return right;
    }
  / left:Expr operator:Op_Expr* right:Node*
    {
        const node= { left };
        right = (right.length == 0)
			        ? null
        			: right[0]["right"] == null
        				? right[0]["left"]
        				: right[0];

        if (right != null)
        {
            node["operator"] = (operator == "" || operator == undefined) ? "<implicit>" : operator[0];
            node["right"] = right;
        }

        return node;
    }


Expr
  = field_exp:Unparen_Expr _*
    {
        return field_exp;
    }
  / Paren_Expr

Paren_Expr
  = "(" node:Node+ ")" _*
	{
        return node[0];
    }
    
Unparen_Expr
  = node:Paren_Expr
    {
        return node;
    }
  / term:Term
    {
        return term;
    }    

Term
  = term:Quoted_Term _*
	{
		return { term };
    }
  / term:Unquoted_Term _*
    {
    	return { term };
    }

Unquoted_Term
  = term:[^: \t\r\n\f\{\}()"+-/^~\[\]]+
    {
        var res = term.join('');
        if (/^(?:AND|OR|NOT)$/.test(res)) {
          var e = new Error('Term can not be AND, OR, NOT')
          e.name = 'SyntaxError'
          e.column = location
          throw e
        }
        return res
    }

Quoted_Term
  = "\"" term:[^"]+ "\"" 
    {
		return term.join("")
    }

Op_Expr
  = _* operator:Op _+
    {
        return operator;
    }
  / _* operator:Op EOF
    {
        return operator;
    }

Op
 = And
 / Or
 / Not

And
  = "AND"
  
Or
  = "OR"

Not
  = "NOT"

_ "whitespace"
  = [ \t\r\n\f]+
  
EOF
  = !.