How to Represent actions in a UML state diagram that may be executed from a base state or as a result of another action from that state

I am creating a UML state diagram to help me plan the card game simulator I'm working on. At the moment I'm stuck on an issue where actions that can be performed from the "Main" state, the state where the game is simply waiting on the player to choose the next move, or as a result of the effect of a card. For example: From the main state, the play can: Play a card Activate the effect of a card already in play Attack with a card Pass Now, any of those actions may trigger one or more effects. If that's the case, the game will enter the "Activation Selection" state. In this state, the player can choose which effects to activate. However, these effects may cause the some of the above actions to be executed which may take the game into other states, but the exact action varies by card. For example: Main state - A player activates a card on the field The activated card's effect is that the player may play a card from the hand Activation Selection state - The player chooses to activate the field card's effect The player selects a card to play When the new card enters play, it may attack immediately Activation Selection state - The player chooses to attack or not Now, this is only a hypothetical situation, and I'm looking for a way to generalise this sort of interaction. How can I represent this in my state diagram? It's entirely possible that a UML state diagram is not the right tool for what I'm trying to do here, so if that's the case, what would be the correct type of diagram to use to plan out my game?

Feb 28, 2025 - 20:27

I am creating a UML state diagram to help me plan the card game simulator I'm working on. At the moment I'm stuck on an issue where actions that can be performed from the "Main" state, the state where the game is simply waiting on the player to choose the next move, or as a result of the effect of a card.

For example: From the main state, the play can:

Play a card
Activate the effect of a card already in play
Attack with a card
Pass

Now, any of those actions may trigger one or more effects. If that's the case, the game will enter the "Activation Selection" state. In this state, the player can choose which effects to activate. However, these effects may cause the some of the above actions to be executed which may take the game into other states, but the exact action varies by card.

For example:

Main state - A player activates a card on the field
The activated card's effect is that the player may play a card from the hand
Activation Selection state - The player chooses to activate the field card's effect
The player selects a card to play
When the new card enters play, it may attack immediately
Activation Selection state - The player chooses to attack or not

Now, this is only a hypothetical situation, and I'm looking for a way to generalise this sort of interaction.

How can I represent this in my state diagram?

It's entirely possible that a UML state diagram is not the right tool for what I'm trying to do here, so if that's the case, what would be the correct type of diagram to use to plan out my game?