Operator Overloading

Building expressions in idol can be done in a very natural way using the C++ operator overloading. The following tables summarize the operators that can be used with the different expression types.

The tables show the return type of the operator when applied to the different expression types. The first column of the table shows the operator applied to the expression type in the first row. The first row of the table shows the expression type of the operator applied to the expression type in the first column. The return type of the operator is shown in the cell at the intersection of the row and column.

Operator: +

operator+	double	Var	LinExpr	AffExpr	QuadExpr	GenerationPattern<Ctr>
double	double	AffExpr	AffExpr	AffExpr	QuadExpr	GenerationPattern<Ctr>
Var	AffExpr	LinExpr	LinExpr	AffExpr	QuadExpr	GenerationPattern<Ctr>
LinExpr	AffExpr	LinExpr	LinExpr	AffExpr	QuadExpr	GenerationPattern<Ctr>
AffExpr	AffExpr	AffExpr	AffExpr	AffExpr	QuadExpr	GenerationPattern<Ctr>
QuadExpr	QuadExpr	QuadExpr	QuadExpr	QuadExpr	QuadExpr
GenerationPattern<Ctr>	GenerationPattern<Ctr>	GenerationPattern<Ctr>	GenerationPattern<Ctr>	GenerationPattern<Ctr>		GenerationPattern<Ctr>

Operator: -

operator-	double	Var	LinExpr	AffExpr	QuadExpr	GenerationPattern<Ctr>
double	double	AffExpr	AffExpr	AffExpr	QuadExpr	GenerationPattern<Ctr>
Var	AffExpr	LinExpr	LinExpr	AffExpr	QuadExpr	GenerationPattern<Ctr>
LinExpr	AffExpr	LinExpr	LinExpr	AffExpr	QuadExpr	GenerationPattern<Ctr>
AffExpr	AffExpr	AffExpr	AffExpr	AffExpr	QuadExpr	GenerationPattern<Ctr>
QuadExpr	QuadExpr	QuadExpr	QuadExpr	QuadExpr	QuadExpr
GenerationPattern<Ctr>	GenerationPattern<Ctr>	GenerationPattern<Ctr>	GenerationPattern<Ctr>	GenerationPattern<Ctr>		GenerationPattern<Ctr>

Operator: *

operator*	double	Var	LinExpr	AffExpr	QuadExpr	GenerationPattern<Ctr>
double	double	LinExpr	LinExpr	AffExpr	QuadExpr	GenerationPattern<Ctr>
Var	LinExpr	LinExpr	QuadExpr	QuadExpr
LinExpr	LinExpr	QuadExpr	QuadExpr	QuadExpr
AffExpr	AffExpr	QuadExpr	QuadExpr	QuadExpr
QuadExpr	QuadExpr
GenerationPattern<Ctr>	GenerationPattern<Ctr>	GenerationPattern<Ctr>*

Note: * GenerationPattern<Ctr> multiplication only works if the GenerationPattern<Ctr> is a constant. Otherwise, an exception is thrown.

Operator: /

operator/	double	Var	LinExpr	AffExpr	QuadExpr	GenerationPattern<Ctr>
double	double
Var	LinExpr
LinExpr	LinExpr
AffExpr	AffExpr
QuadExpr	QuadExpr
GenerationPattern<Ctr>	GenerationPattern<Ctr>