feat: introduce transaction builder crate (#338)

pallas-txbuilder/src/lib.rs

@@ -0,0 +1,33 @@
+mod babbage;
+mod transaction;
+
+pub use babbage::BuildBabbage;
+pub use transaction::model::{BuiltTransaction, Input, Output, ScriptKind, StagingTransaction};
+
+#[derive(Debug, Clone, PartialEq, thiserror::Error)]
+pub enum TxBuilderError {
+    /// Provided bytes could not be decoded into a script
+    #[error("Transaction has no inputs")]
+    MalformedScript,
+    /// Provided bytes could not be decoded into a datum
+    #[error("Could not decode datum bytes")]
+    MalformedDatum,
+    /// Provided datum hash was not 32 bytes in length
+    #[error("Invalid bytes length for datum hash")]
+    MalformedDatumHash,
+    /// Input, policy, etc pointed to by a redeemer was not found in the transaction
+    #[error("Input/policy pointed to by redeemer not found in tx")]
+    RedeemerTargetMissing,
+    /// Provided network ID is invalid (must be 0 or 1)
+    #[error("Invalid network ID")]
+    InvalidNetworkId,
+    /// Transaction bytes in built transaction object could not be decoded
+    #[error("Corrupted transaction bytes in built transaction")]
+    CorruptedTxBytes,
+    /// Public key generated from private key was of unexpected length
+    #[error("Public key for private key is malformed")]
+    MalformedKey,
+    /// Asset name is too long, it must be 32 bytes or less
+    #[error("Asset name must be 32 bytes or less")]
+    AssetNameTooLong,
+}