This represents the major component of the Cardano protocol version. The ledger can only supply the major component of the protocol version, not the minor component, and Plutus should only need to care about the major component anyway. This relies on careful understanding between us and the ledger as to what this means.

Shelley era was introduced in protocol version 2.0

Allegra era was introduced in protocol version 3.0

Mary era was introduced in protocol version 4.0

Alonzo era was introduced in protocol version 5.0

The Vasil HF introduced the Babbage era and Plutus V2

Valentine was an intra-era HF where builtin functions VerifyEcdsaSecp256k1Signature and VerifySchnorrSecp256k1Signature were enabled.

The Chang HF introduced the Conway era and Plutus V3

The Plomin HF was an intra-era HF where some new builtin functions were introduced in Plutus V2 and V3.

The van Rossem HF will be an intra-era HF.

The set of protocol versions that are "known", i.e. that have been released and have actual differences associated with them. This is currently only used for testing, so efficiency is not parmount and a list is fine.

This is a placeholder for when we don't yet know what protocol version will be used for something. It's a very high protocol version that should never appear in reality.

We should not assign names to future protocol versions until it's confirmed that they are correct, otherwise we could accidentally associate something with the wrong protocol version.

The Plutus ledger language. These are entirely different script languages from the ledger's perspective, which on our side are interpreted in very similar ways.

It is a simple enumerated datatype (there is no major and minor components as in protocol version) and the ordering of constructors is essential for deriving Enum,Ord,Bounded.

IMPORTANT: this is different from the Plutus Core language version, Version

Query the protocol version that a specific Plutus ledger language was first introduced in.

Which Plutus language versions are available in the given MajorProtocolVersion? See Note [New builtins/language versions and protocol versions]. This function (and others in this module) assumes that once a LL is available it remains available in all later PVs and that if m <= n, PlutusVm is introduced no later than PlutusVn.

A map indicating which Plutus Core versions were introduced in which MajorProtocolVersion and PlutusLedgerLanguage. Each version should appear at most once. This must be updated when new versions are added. See Note [New builtins/language versions and protocol versions]

Which Plutus Core language versions are available in the given PlutusLedgerLanguage and MajorProtocolVersion?

Given a ledger language, return a map indicating which builtin functions were introduced in which MajorProtocolVersion. This must be updated when new builtins are added. It is not necessary to add entries for protocol versions where no new builtins are added. See Note [New builtins/language versions and protocol versions]

Return a set containing the builtins which are available in a given LL in a given PV. All builtins are available in all LLs from vanRossemPV onwards.