public void Optimize_AdditionMultiplicationConstants()
{
// 1 + 2 * 3 => 7
var ast = new SqlInfixOperationNode
{
Left = new SqlNumberNode(1),
Operator = new SqlOperatorNode("+"),
Right = new SqlInfixOperationNode
{
Left = new SqlNumberNode(2),
Operator = new SqlOperatorNode("*"),
Right = new SqlNumberNode(3)
}
};
var target = new ExpressionOptimizeVisitor();
var result = target.Visit(ast);
result.Should().MatchAst(new SqlNumberNode(7));
}
private ISqlNode ParseBooleanExpression5(ITokenizer t)
{
// <BooleanExpression3> ("AND" | "OR") <BooleanExpression3>
var left = ParseBooleanExpression4(t);
while (t.Peek().IsKeyword("AND", "OR"))
{
var op = new SqlOperatorNode(t.GetNext());
var right = ParseBooleanExpression4(t);
left = new SqlInfixOperationNode
{
Location = op.Location,
Left = left,
Operator = op,
Right = right
};
}
return(left);
}
private ISqlNode ParseScalarExpression3(ITokenizer t)
{
// Operators with + - precidence
// <Expression2> (<op> <Expression2>)+
var left = ParseScalarExpression2(t);
while (t.Peek().IsSymbol("+", "-", "&", "^", "|"))
{
var op = new SqlOperatorNode(t.GetNext());
var right = ParseScalarExpression2(t);
left = new SqlInfixOperationNode
{
Location = op.Location,
Left = left,
Operator = op,
Right = right
};
}
return(left);
}
public ISqlNode VisitInfixOperation(SqlInfixOperationNode n)
{
void ToStringChild(ISqlNode node)
{
if (node is SqlInfixOperationNode)
{
Append("(", node, ")");
return;
}
Visit(node);
}
if (n.IsUnionOperation())
{
Visit(n.Left);
AppendLineAndIndent();
Visit(n.Operator);
AppendLineAndIndent();
Visit(n.Right);
}
else if (n.IsBooleanOperation())
{
ToStringChild(n.Left);
AppendLineAndIndent();
Visit(n.Operator);
Append(" ");
ToStringChild(n.Right);
}
else
{
ToStringChild(n.Left);
Append(" ");
Visit(n.Operator);
Append(" ");
ToStringChild(n.Right);
}
return(n);
}
public override ISqlNode VisitInfixOperation(SqlInfixOperationNode n)
{
n = base.VisitInfixOperation(n) as SqlInfixOperationNode;
if (n.IsArithmeticOperation())
{
if (n.Left is SqlNumberNode nl && n.Right is SqlNumberNode nr)
{
var newNode = n.Operator.Apply(nl, nr);
newNode.Location = n.Location;
return(newNode);
}
if (n.Left is SqlStringNode sl && n.Right is SqlStringNode a)
{
var newNode = n.Operator.Apply(sl, a);
newNode.Location = n.Location;
return(newNode);
}
}
// TODO: If the operation is AND or OR and both sides can reduce to one of (TRUE, FALSE), we can reduce the whole thing
return(n);
}
