rename last and first to latest and oldest

mysticeti/validator.nim

@@ -30,10 +30,10 @@ func membership*(validator: Validator): CommitteeMember =
   validator.membership
 
 func round*(validator: Validator): uint64 =
-  validator.rounds.last.number
+  validator.rounds.latest.number
 
 func nextRound*(validator: Validator) =
-  validator.rounds.addNextRound()
+  validator.rounds.addNewRound()
 
 func skips(blck: Block, round: uint64, author: CommitteeMember): bool =
   for parent in blck.parents:
@@ -42,7 +42,7 @@ func skips(blck: Block, round: uint64, author: CommitteeMember): bool =
   true
 
 func updateSkipped(validator: Validator, supporter: Block) =
-  if previous =? validator.rounds.last.previous:
+  if previous =? validator.rounds.latest.previous:
     for member in previous.members:
       let slot = previous[member]
       if supporter.skips(previous.number, member):
@@ -63,29 +63,29 @@ func updateCertified(validator: Validator, certificate: Block) =
       proposal.certifyBy(certificate.id, stake)
 
 proc propose*(validator: Validator, transactions: seq[Transaction]): auto =
-  assert validator.rounds.last[validator.membership].proposals.len == 0
+  assert validator.rounds.latest[validator.membership].proposals.len == 0
   var parents: seq[BlockId[Validator.Hashing]]
-  if previous =? validator.rounds.last.previous:
+  if previous =? validator.rounds.latest.previous:
     for slot in previous.slots:
       if slot.proposals.len == 1:
         parents.add(slot.proposals[0].blck.id)
   let blck = Block.new(
     author = validator.membership,
-    round = validator.rounds.last.number,
+    round = validator.rounds.latest.number,
     parents = parents,
     transactions = transactions
   )
-  validator.rounds.last.add(blck)
+  validator.rounds.latest.add(blck)
   validator.updateCertified(blck)
   validator.identity.sign(blck)
 
 func receive*(validator: Validator, signed: SignedBlock) =
-  validator.rounds.last.add(signed.blck)
+  validator.rounds.latest.add(signed.blck)
   validator.updateSkipped(signed.blck)
   validator.updateCertified(signed.blck)
 
 func status*(validator: Validator, blck: Block): ?SlotStatus =
-  if round =? validator.rounds.first.find(blck.round):
+  if round =? validator.rounds.oldest.find(blck.round):
     some round[blck.author].status
   else:
     none SlotStatus
@@ -114,8 +114,8 @@ func updateIndirect(validator: Validator, slot: ProposerSlot, round: Round) =
 
 iterator committed*(validator: Validator): auto =
   var done = false
-  var current = some validator.rounds.first
-  while not done and round =? current:
+  while not done:
+    let round = validator.rounds.oldest
     for slot in round.slots:
       if slot.status == SlotStatus.undecided:
         validator.updateIndirect(slot, round)
@@ -128,5 +128,4 @@ iterator committed*(validator: Validator): auto =
       of SlotStatus.commit:
         yield slot.commit()
     if not done:
-      validator.rounds.remove(round)
-      current = round.next
+      validator.rounds.removeOldestRound()

mysticeti/validator/rounds.nim

@@ -75,40 +75,40 @@ func add*(round: Round, blck: Block): auto =
     slot.add(blck)
 
 type Rounds*[Hashing] = object
-  first, last: Round[Hashing]
+  oldest, latest: Round[Hashing]
 
 func new*(T: type Rounds, slots: int, start: uint64 = 0): T =
   let round = Round[T.Hashing].new(start, slots)
-  T(first: round, last: round)
+  T(oldest: round, latest: round)
 
-func first*(rounds: Rounds): auto =
-  rounds.first
+func oldest*(rounds: Rounds): auto =
+  rounds.oldest
 
-func last*(rounds: Rounds): auto =
-  rounds.last
+func latest*(rounds: Rounds): auto =
+  rounds.latest
 
 func wave*(rounds: Rounds): auto =
   # A wave consists of 3 rounds: proposing -> voting -> certifying
-  type Round = typeof(rounds.last)
-  let certifying = rounds.last
+  type Round = typeof(rounds.latest)
+  let certifying = rounds.latest
   if voting =? certifying.previous:
     if proposing =? voting.previous:
       return some (proposing, voting, certifying)
   none (Round, Round, Round)
 
-func addNextRound*(rounds: var Rounds) =
-  let previous = rounds.last
+func addNewRound*(rounds: var Rounds) =
+  let previous = rounds.latest
   let next = Round[Rounds.Hashing].new(previous.number + 1, previous.slots.len)
   next.previous = some previous
   previous.next = some next
-  rounds.last = next
+  rounds.latest = next
 
-func remove*(rounds: var Rounds, round: Round) =
-  if previous =? round.previous:
-    previous.next = round.next
-  else:
-    rounds.first = !round.next
-  if next =? round.next:
-    next.previous = round.previous
-  else:
-    rounds.last = !round.previous
+func removeOldestRound*(rounds: var Rounds) =
+  assert rounds.oldest.previous.isNone
+  assert rounds.oldest.next.isSome
+  type Round = typeof(rounds.oldest)
+  let oldest = rounds.oldest
+  let next = !oldest.next
+  next.previous = none Round
+  oldest.next = none Round
+  rounds.oldest = next

tests/mysticeti/validator/testRounds.nim

@@ -8,12 +8,12 @@ suite "Validator Rounds":
 
   test "members are ordered round-robin for each round":
     var rounds = Rounds.new(4)
-    check toSeq(rounds.last.members) == @[0, 1, 2, 3].mapIt(CommitteeMember(it))
-    rounds.addNextRound()
-    check toSeq(rounds.last.members) == @[1, 2, 3, 0].mapIt(CommitteeMember(it))
-    rounds.addNextRound()
-    check toSeq(rounds.last.members) == @[2, 3, 0, 1].mapIt(CommitteeMember(it))
-    rounds.addNextRound()
-    check toSeq(rounds.last.members) == @[3, 0, 1, 2].mapIt(CommitteeMember(it))
-    rounds.addNextRound()
-    check toSeq(rounds.last.members) == @[0, 1, 2, 3].mapIt(CommitteeMember(it))
+    check toSeq(rounds.latest.members) == @[0, 1, 2, 3].mapIt(CommitteeMember(it))
+    rounds.addNewRound()
+    check toSeq(rounds.latest.members) == @[1, 2, 3, 0].mapIt(CommitteeMember(it))
+    rounds.addNewRound()
+    check toSeq(rounds.latest.members) == @[2, 3, 0, 1].mapIt(CommitteeMember(it))
+    rounds.addNewRound()
+    check toSeq(rounds.latest.members) == @[3, 0, 1, 2].mapIt(CommitteeMember(it))
+    rounds.addNewRound()
+    check toSeq(rounds.latest.members) == @[0, 1, 2, 3].mapIt(CommitteeMember(it))