7
votes
Accepted
Where is the on-chain code actually stored?
As stated by Samuel, the code that a validator runs to check whether a transaction is valid is sent and stored in the transaction body as an input.
So all scripts, be they Plutus or Native scripts, ...
- 1,872
6
votes
Committing a database to the ledger without storing it on the ledger?
You can use Merkle tree's for this! This is an inverted tree like data structure that uses hashes to create a root hash that is uniquely defined by its leafs, the leafs are the nodes in the lowest ...
- 1,872
4
votes
Accepted
Is function "isPayToScriptOut" unsafe?
Your deductions are partially correct. isPayToScriptOut looks at the credentials of an address (1) and return true if it is a script address, false if it is a public key credential. It thus does not ...
- 1,872
3
votes
Accepted
Confusion regarding findOwnInput function with on-chain code
Calling findOwnInput in a validator returns the value contained in the Script-UTxO that is currently being validated. In your example above it is the one with 2 Ada in it.
Your example above is, ...
- 1,521
3
votes
On-chain and Off-chain code
Yes, that's correct. On-chain is exactly what it says. It's logic that happens on every validator syncing the chain. The unique thing with plutus is the on-chain and off-chain code can live together ...
- 2,847
3
votes
Accepted
Is really any token metadata stored on chain? Or is it the mint TX metadata?
Yes there is NFT metadata stored on-chain and yes they are stored initially on the mint tx although you can update it later (basically overriding it in a new tx). If the NFT metadata follow the CIP25 ...
- 216
3
votes
Accepted
Overuse of resources when comparing for equality of VALUES (==)
Copying my answer from the Github issue here as well:
We have hit the same issue lately. It is due to how the == function in the Eq Value instance is implemented.
A value is logically a Map ...
- 588
2
votes
Accepted
Is there a way for a validator to get the current time?
The usual way to handle time in Plutus is using Slot ranges. This means that the script does not query the time. Instead it checks that the validation happens in a given slot interval that corresponds ...
- 83
2
votes
How to get a base 16 hex BuiltinString from getTxId
I was able to resolve this issue by converting (encoding) the BuiltinByteString from getTxId into a hex format. From there I was able to inpsect the hex digits. Below is an onchain encodeHex ...
- 297
2
votes
Can Queries To the Chain be made From Plutus Smart Contracts?
The way I understood things from last Q&A session with Lars, no, you can't. You can only see the current transaction, not the history of an address.
- 320
2
votes
Accepted
How can I configure and send a transaction to the Cardano chain using python
Checkout PyCardano. It is able to serialize python objects to datum and redeemers. Maybe this test example can help: https://github.com/cffls/pycardano/blob/main/integration-test/test/test_all.py#L217 ...
- 393
2
votes
Accepted
How do Endpoints work?
In Plutus apps, the mechanism for requesting inputs is called "endpoints".
All endpoints that an app wants to use must be declared as part of the type of the app. The set of all endpoints of ...
- 1,095
2
votes
How to parse TokenName to Integer
I had trouble with the same thing, just going the opposite direction, Slot -> TokenName (Slot is just an Integer under the hood). After a bunch of pain I ended up just coding my own parsing logic:
-...
- 3,247
2
votes
traceIfFalse is it possible to pass a string not "fixed"
This is probably not possible as the redeemer code is manipulated/examined from within a template haskell splice and you are running into what is called the "template haskell stage restriction&...
- 2,613
2
votes
Accepted
How To Verify The Code Of A SmartContract?
You compile the code yourself to see if the address you arrive at aligns with what's live.
- 310
1
vote
Accepted
How to do on-chain Integer pattern matching?
There is problem with pattern matching on Integer types according to Input Output Global. The Plutus compiler will currently reject any pattern matching on Integer types.
Therefore the best solution ...
- 1,172
1
vote
Accepted
How to compare BuiltinByteStrings onchain?
This is how I've done the integer conversion in the past. Might need some minor updating:
{-# INLINEABLE intToString #-}
intToString :: Integer -> Builtins.String
intToString i = Prelude.foldr ...
- 3,247
1
vote
Accepted
How can a validator script be used to mint native tokens, in addition to perform other checks?
You need a separate minting policy to mint the tokens.
we want a smart contract (validator script)
I tend to think of smart contracts as including a set of validators and policies, not just one ...
- 3,247
1
vote
Accepted
Can UTxO sit at a minting policy (currency symbol), like at a validator script address?
As you said, minting policies is part of a transaction and and is not part of a script address UTxO, so it doesn't make sense saying "UTxO sitting at a minting policy", since the minting ...
- 988
1
vote
How to optimize Plutus smart contracts?
Mlabs created excelent tool to quickly check and analyse size of smartcontracts. Github repo is here
- 599
1
vote
Accepted
How to optimize Plutus smart contracts?
I am building a dApp myself and I am running into similar issues related to hitting the current mainnet's maxTxExUnits upper boundaries of exUnitsMem and exUnitsSteps.
In regards to question 4:
You ...
- 1,172
1
vote
Accepted
How to know which module to import?
Some of these are reexported versions of others. This means some of them are not necessary. Also PlutusTx.Prelude should be included in all projects as it maps types into PlutusTx which complies with ...
- 962
1
vote
Accepted
How do you deploy ready made AI on chain
I have done that as well for Kucoin Binance etc python is great for backend data analisis... Well.. BlockChain are just transactions... you should be able to do a BlockChain a transaction from your ...
- 897
1
vote
How do you deploy ready made AI on chain
I am not very knowledgeable when it comes to AI, but I'm pretty sure right now it's impossible to have one on-chain for two reasons. First, it would be too computationally heavy, so the current CPU ...
- 988
1
vote
How to PreSign a transaction
Scripts on the ledger are passive, they do not act unless a party sends a transaction that propagates the state of the script.
If I understand correctly, you want a vesting scheme, this is possible. ...
- 1,872
1
vote
Accepted
How to get information about UTxOs which created locking transaction on the on-chain?
In TxOut you have a field txOutAddress that you can use for this:
data TxOut = TxOut {
txOutAddress :: Address,
txOutValue :: Value,
txOutDatumHash :: Maybe DatumHash
}
Use it to extract ...
- 1,521
1
vote
How does one check a pool's delegation history?
If you do not want to setup cardano-db-sync, try blockfrost.io with the /epochs/{number}/blocks/{pool_id} endpoint.
- 7,279
1
vote
Accepted
How does one check a pool's delegation history?
If you need any kind of specific on chain information that isn't found on third party explorers like Cardanoscan, you'd have to use db-sync yourself. (It's what all the explorers use)
To quote ...
- 3,699
1
vote
Accepted
How does custom Plutus data type map to cardano-cli --tx-in-datum-file content?
Here is an example of a haskell executable that will convert any of your custom data types to the right JSON format :
https://github.com/OnChainLabs/Martify/blob/main/app/datum-json.hs
In this file we ...
- 319
1
vote
Retrieve only digit from TokenName and use onchain
given the request on way would be the following:
getIdFromTokenName :: TokenName -> Integer
getIdFromTokenName tn = getIdFromStr 0 $ (BS8.unpack . unTokenName) tn -- BS8.unpack :: ByteString -> ...
- 1,098
Only top scored, non community-wiki answers of a minimum length are eligible