// Arthmentic Simplification:
/*
* +/- zero to a column, or multiply/divide a column by 1
*/
internal bool IsArithIdentity(ConstExpr lce, ConstExpr rce)
{
ConstExpr ve = lce != null ? lce : rce;
ColExpr ce = (children_[0] is ColExpr) ? (ColExpr)children_[0] : (children_[1] is ColExpr ? (ColExpr)children_[1] : null);
if (ce == null)
{
return(false);
}
if (!(TypeBase.IsNumberType(ve.type_) && TypeBase.IsNumberType(ce.type_)))
{
return(false);
}
if ((op_ == "+" || op_ == "-") && ve.IsZero())
{
return(true);
}
if ((op_ == "*" || op_ == "/") && ve.IsOne())
{
return(true);
}
return(false);
}
internal Expr SimplifyArithmetic(ConstExpr lve, ConstExpr rve)
{
// we know we have a BinExpr with numeric children
ConstExpr ve = lve != null ? lve : rve;
ColExpr ce = (children_[0] is ColExpr) ? (ColExpr)children_[0] : (children_[1] is ColExpr ? (ColExpr)children_[1] : null);
if (ce is null || ve is null)
{
return(this);
}
// Col + 0, or Col - 0 => return col
if ((op_ == "+" || op_ == "-") && ve.IsZero())
{
return(ce);
}
if ((op_ == "*" || op_ == "/") && ve.IsOne())
{
return(ce);
}
return(this);
}