I'm getting this error "Order rejected by script of asset" while creating an smart asset trading only with WAVES, how to fix it?

Question

I am trying to create an asset trading only with WAVES, and I have created an smart asset on Waves testnet using RIDE language, but now, I can't trade this asset with WAVES, thanks!

let WavesId = base58'WAVES'
match tx {
  case t : ExchangeTransaction => 
  t.sellOrder.assetPair.priceAsset == WavesId || t.sellOrder.assetPair.amountAsset == WavesId
  case _ => true
}

This is the error message:

Answer 1

For defined trading, you need to determine if Smart asset is paired with Waves like the following:

 let withWaves = (!isDefined(e.sellOrder.assetPair.priceAsset) || !isDefined(e.sellOrder.assetPair.amountAsset))

Instead of t.sellOrder.assetPair.priceAsset == WavesId || t.sellOrder.assetPair.amountAsset == WavesId