TxEvaluator

class cometa.transaction_builder.evaluation.tx_evaluator.TxEvaluatorProtocol(*args, **kwargs)

Bases: Protocol

Protocol defining the interface for transaction evaluators.

Transaction evaluators calculate the execution units required for Plutus scripts in a transaction. This is essential for determining accurate transaction fees when scripts are involved.

Implement this protocol to create custom transaction evaluators (e.g., using Blockfrost, Koios, or local evaluation).

Example

>>> class MyEvaluator:
...     def get_name(self) -> str:
...         return "MyEvaluator"
...
...     def evaluate(
...         self,
...         transaction: Transaction,
...         additional_utxos: List[Utxo],
...     ) -> List[Redeemer]:
...         # Custom evaluation logic
...         # Call external service, run local UPLC, etc.
...         return redeemers

get_name()

Get the human-readable name of this evaluator.

Returns:

The evaluator name (e.g., “Blockfrost”, “Koios”, “Local”).

Return type:

str

evaluate(transaction, additional_utxos)

Evaluate the execution units required for a transaction.

This method calculates the execution units needed for each Plutus script in the transaction.

Parameters:

• transaction (Transaction) – The transaction to evaluate.

• additional_utxos (Union['UtxoList', List['Utxo'], None]) – Optional additional UTXOs needed for evaluation.

Returns:

A list of Redeemer objects with computed execution units.

Raises:

Exception – If evaluation fails.

Return type:

List[‘Redeemer’]

__init__(*args, **kwargs)

cometa.transaction_builder.evaluation.tx_evaluator.TxEvaluator

alias of TxEvaluatorProtocol