I'm tinkering with a framework to implement board games in c# (similar to boardgame.io in JS) part of that is getting a handle on turn structures. (What is a round? what is a turn? who gets to go when? etc)
So I've gone through all my games and looked for recurring patterns and exceptions to them and here's what I've collected so far:
There's always at least one structure that handles how player act or "take turns"
the vast majority of games do traditional turns - one player does things, then then another,
usually in a fixed order maybe going forward some times and backward other times.
sometimes the order can change
also possible are:
turn order decks (you don't know who goes next but know that everyone gets a turn)
action tracks (where whoever is furthest back gets to go next, possibly resulting in an uneven number of turns)
the next player is dependent on an action of the previous player
it's also possible that players can play simultaneously
a complete free for all is pretty common
it's also possible that players can act freely to some point, then have to wait for everyone else to catch up
another consideration, both for concurrent and sequential play is that sometimes some players are excluded (Codenames for example lets all guessers on a given team act concurrently but not the leaders or the other team)
there can be different rules at different times (like first picking a tile in sequence then everyone can place it simultaneously)
and there can be nested rules (like every player gets to run an auction but in every auction each player get's to bid as well)
one relatively common special case is where certain actions on a player's turn result in decisions being needed from other players (trades, attacks, "each player ..." effects)
there are often structures that simply subdivide another structure
they can occur at any level. A game may be divided into "setup" and "play", a round could be divided into different phases but a single player's turn might also be divided into smaller steps.
these subdivision usually restrict / specify which actions are allowed in them
these subdivision often come with limits like: you can only do N actions
sometimes a player can "pass" sometimes they cannot
I'm wondering if anyone can think of an instance that is not covered by these "rules".
Interesting challenge! Its curious how programming leads to this systematic analysis and the revelation of complexity even for “simple” things
There are some games where the turn order can be influenced that I am not sure are covered by your rules:
5 tribes has a auction-style system by players committing a certain amount of currency to occupy a specific slot in the turn. For 2 player game each player goes twice and auctions twice for the upcoming turn
Bot factory is using a rotating worker placing mechanic with 4 sections with each 2-3 worker position, with the limitation that you cannot remain in the same section
Castles of Burgundy player order divided in 5 turns divided into 5 phases which changes depending on playing certain tiles (ships and specific monasteries)
oh nice! The 5 tribes is probably gonna be a variant of the "action track" system.
Not quite sure I understand the "Bot Factory" example. Is that more than just a simple sequential structure and the restriction is only about what you can do this or next turn?
Burgundy: That'll also be interesting. Could do that by transitioning straight to the next applicable phase, or could keep the structure simpler and just auto-terminate any phases where the player has nothing to do.
Bot factory has a turn order track that is read from right to left. It has roughly 10 positions that are separated into 4 regions. You can not choose a similar spot in the same region as your previous turn. Additionally, there is a worker that will always move from one section to the next, occupying the next available slot. This is the AI-worker and essentially a fifth player with special rules.
Burgundy player turn is determined also by a track, players can occupy the same slot. The position is marked by stackable player tokens with the top player of the stack going first. The last player to advance to the next section of the track will play first but the next player to advance there will be stacked on top and thus become the first.
However, there is an ability that can be acquired by one player during the game which makes their stackable player token always be on the top, irrespective of when others join their stack
I love Death in Space's turn order style. One of the players goes first, then they decide which enemy goes next. Then when the enemy is done, they decide which player goes next. This repeats until one side is out of participants, and then the other team's participants go in whatever order they like.
This avoids any discussion for who goes next, and helps cut down on long winded strategy discussions because there's no guarantee to the turn order. Gameplay becomes way more focused around taking advantage of the current situation, but you can still plan a strategy.
Rather than trying to define abstractions for turns and rounds, maybe you could implement the game state (and possibly individual players) as a finite state machine.
In this model, the way you set up the states and transitions for a particular game will capture its idiosyncracies in turn and round order.
That's what I'm currently doing. But I'm not yet sure if a straight FSM is such a great fit. There's not good mapping for the concept of turns in a single level FSM. You can do it of course but if you have multiple such models or nested instances where each player gets to react to specific actions on each player's regular turn, each of them is gonna push the the properties needed to manage that into the shared state.
So I'm currently at nested state machines. This way the implementation details for alternating between players can be hidden from the higher level states.
In Galaxy Trucker, there is a "distance" or "race" track that manages turn order.
Once all players have built a space ship (simultaneously picking and laying tiles), players place markers on a race track. The first player to finish building their ship is in first, the second player behind them, and so on. I believe there is one empty space between them all as well.
The rest of the game is flipping over event cards one by one and resolving them. Some events are resolved by all players simultaneously. Others are resolved in the order on the race track. First player resolves part of the event. If there's anything left to resolve, second player resolves part, and so on.
Part of resolving an event might involve moving a certain number of steps up or down the race track, skipping over any occupied spaces.
So turn order here would be complicated to work out, especially in a FSM. Effect cards may change turn order, but not always. There may be empty space between two players in the turn order that gets reduced or increased instead. I suppose you could model it with N real players and then X place-holder players that don't actually take their turn.
In my current draft you can basically say "here is what one player get's to do in their turn" and tell the framework to make a machine that let's every player run through that in some kind of sequence. For now the sequence is fixed. But ultimately all that GT needs is a recalculation of the order after every card. That's relatively simple to add with a post-action trigger.
Thanks a lot for those examples! Totally forgot about those "extra turn" effects. That'll be fun.
I had already considered a bunch of concepts about how a phase can end but not that it might be completely independent from any player action.
The Gloomhaven scenario probably is the easiest of these since it is merely a variant of the general "player actions result in change of player order" case
Action selection games might ruin your idea, like in Race for the Galaxy, everyone picks actions and everyone gets to do all actions selected. Puerto Rico is similar, but actions are selected in turn order instead of simultaneously.
Dominion has the possession card, which gives player A control over player B's turn, and player A gets all cards acquired by player B. There's also cards that grant extra turns, with varying conditions.
Red Dragon Inn has a basic turn order, but every player have many cards that can be played anytime or in reaction to certain events. There's also the gambling mechanic which gives everyone a turn in a mini game that doesn't affect the main turns.