PluralFormsNode LogicalAndExpression()
{
PluralFormsNode p = EqualityExpression();
if (p == null)
{
return(null);
}
PluralFormsNode ln = p; // left
if (Token.TokenType == PluralFormsToken.Type.LogicalAnd)
{
PluralFormsNode un = new PluralFormsNode(new PluralFormsToken(Token)); // up
if (!NextToken())
{
return(null);
}
p = LogicalAndExpression();
if (p == null)
{
return(null);
}
PluralFormsNode rn = p; // right
if (rn.Token.TokenType == PluralFormsToken.Type.LogicalAnd)
{
// transform 1 && (2 && 3) -> (1 && 2) && 3
// u r
// l r -> u 3
// 2 3 l 2
un.SetNode(0, ln);
un.SetNode(1, rn.ReleaseNode(0));
rn.SetNode(0, un);
return(rn);
}
un.SetNode(0, ln);
un.SetNode(1, rn);
return(un);
}
return(ln);
}
PluralFormsNode LogicalOrExpression()
{
PluralFormsNode p = LogicalAndExpression();
if (p == null)
{
return(null);
}
PluralFormsNode ln = p;
if (Token.TokenType == PluralFormsToken.Type.LogicalOr)
{
PluralFormsNode un = new PluralFormsNode(new PluralFormsToken(Token));
if (!NextToken())
{
return(null);
}
p = LogicalOrExpression();
if (p == null)
{
return(null);
}
PluralFormsNode rn = p; // right
if (rn.Token.TokenType == PluralFormsToken.Type.LogicalOr)
{
// see logicalAndExpression comment
un.SetNode(0, ln);
un.SetNode(1, rn.ReleaseNode(0));
rn.SetNode(0, un);
return(rn);
}
un.SetNode(0, ln);
un.SetNode(1, rn);
return(un);
}
return(ln);
}