private void AddMiscFunctions()
{
Register(config => config.Named("iif")
.WithBooleanParameter("condition")
.WithDynamicParameter("ifTrue")
.WithDynamicParameter("ifFalse")
.WhenExecute(context => SystemFunctions.Iif(context))
.ReturnsType(IifReturnType));
Register(config => config.Named("i_frule_convert")
.WithDynamicParameter("rule")
.WhenExecute(context => Simple(context, args => SystemFunctions.FRuleConvert(args[0])))
.ReturnsType(context => {
var argType = ReturnType(context.Arguments[0], context);
return(argType is StringType ? (SqlType)PrimitiveTypes.Numeric() : (SqlType)PrimitiveTypes.String());
}));
}