public void VisitUnaryExpression(AstUnaryExpression unaryExpression)
{
Assert.IsType <AstUnaryExpression>(this.expected);
var expectedAst = (AstUnaryExpression)this.expected;
Assert.Equal(expectedAst.Operator, unaryExpression.Operator);
AssertVisit(expectedAst.Expression, unaryExpression.Expression);
}
internal void ParseExpression_UnaryExpression_SupportForPlusOperator()
{
var expectedAst = new AstUnaryExpression
{
Operator = CmdTokenKind.Plus,
Expression = new AstNumberExpression
{
Value = "6"
}
};
AstAssert.Expression(expectedAst, "+6");
}
public void Visit(AstUnaryExpression expr)
{
var opName =
String.IsNullOrEmpty(expr.OperatorSymbol)
? expr.OperatorName
: expr.OperatorSymbol;
var node =
StepsCluster
.AddNode(NodeInfo.NodeName)
.SetLabel(opName.Bold());
FollowExpression(expr.Operand, node.ToNodeRef(DotCompass.West));
}
public override AstNode VisitUnaryExpression(AstUnaryExpression node)
{
var root = AstExpression.Var("ROOT", isCurrent: true);
if (TryOptimizeSizeOfElements(out var optimizedExpression))
{
return(optimizedExpression);
}
if (TryOptimizeAccumulatorOfElements(out optimizedExpression))
{
return(optimizedExpression);
}
if (TryOptimizeAccumulatorOfMappedElements(out optimizedExpression))
{
return(optimizedExpression);
}
return(base.VisitUnaryExpression(node));
bool TryOptimizeSizeOfElements(out AstExpression optimizedExpression)
{
// { $size : "$_elements" } => { __agg0 : { $sum : 1 } } + "$__agg0"
if (node.Operator == AstUnaryOperator.Size)
{
if (node.Arg is AstGetFieldExpression argGetFieldExpression &&
argGetFieldExpression.FieldName is AstConstantExpression constantFieldNameExpression &&
constantFieldNameExpression.Value.IsString &&
constantFieldNameExpression.Value.AsString == "_elements")
{
var accumulatorExpression = AstExpression.AccumulatorExpression(AstAccumulatorOperator.Sum, 1);
var accumulatorFieldName = _accumulators.AddAccumulatorExpression(accumulatorExpression);
optimizedExpression = AstExpression.GetField(root, accumulatorFieldName);
return(true);
}
}
optimizedExpression = null;
return(false);
}
bool TryOptimizeAccumulatorOfElements(out AstExpression optimizedExpression)
{
// { $accumulator : { $getField : { input : "$$ROOT", field : "_elements" } } } => { __agg0 : { $accumulator : "$$ROOT" } } + "$__agg0"
if (node.Operator.IsAccumulator(out var accumulatorOperator) &&
node.Arg is AstGetFieldExpression getFieldExpression &&
getFieldExpression.FieldName is AstConstantExpression getFieldConstantFieldNameExpression &&
getFieldConstantFieldNameExpression.Value.IsString &&
getFieldConstantFieldNameExpression.Value == "_elements" &&
getFieldExpression.Input is AstVarExpression getFieldInputVarExpression &&
getFieldInputVarExpression.Name == "ROOT")
{
var accumulatorExpression = AstExpression.AccumulatorExpression(accumulatorOperator, root);
var accumulatorFieldName = _accumulators.AddAccumulatorExpression(accumulatorExpression);
optimizedExpression = AstExpression.GetField(root, accumulatorFieldName);
return(true);
}
optimizedExpression = null;
return(false);
}
bool TryOptimizeAccumulatorOfMappedElements(out AstExpression optimizedExpression)
{
// { $accumulator : { $map : { input : { $getField : { input : "$$ROOT", field : "_elements" } }, as : "x", in : f(x) } } } => { __agg0 : { $accumulator : f(x => root) } } + "$__agg0"
if (node.Operator.IsAccumulator(out var accumulatorOperator) &&
node.Arg is AstMapExpression mapExpression &&
mapExpression.Input is AstGetFieldExpression mapInputGetFieldExpression &&
mapInputGetFieldExpression.FieldName is AstConstantExpression mapInputconstantFieldExpression &&
mapInputconstantFieldExpression.Value.IsString &&
mapInputconstantFieldExpression.Value.AsString == "_elements" &&
mapInputGetFieldExpression.Input is AstVarExpression mapInputGetFieldVarExpression &&
mapInputGetFieldVarExpression.Name == "ROOT")
{
var rewrittenArg = (AstExpression)AstNodeReplacer.Replace(mapExpression.In, (mapExpression.As, root));
var accumulatorExpression = AstExpression.AccumulatorExpression(accumulatorOperator, rewrittenArg);
var accumulatorFieldName = _accumulators.AddAccumulatorExpression(accumulatorExpression);
optimizedExpression = AstExpression.GetField(root, accumulatorFieldName);
return(true);
}
optimizedExpression = null;
return(false);
}
}
