sharplib/imm/FSM.cs
2024-04-07 19:21:52 -07:00

64 lines
987 B
C#

using System;
namespace imm;
public record class Context : imm.Recorded<Context>
{
}
public record class State<T, CTX> : imm.Recorded<State<T, CTX>>
where T : State<T, CTX>
where CTX : Context
{
virtual public (CTX, T) onEnter(CTX ctx, State<T, CTX> oldState)
{
return (ctx, (T)this);
}
virtual public (CTX, T) onExit(CTX ctx, State<T, CTX> newState)
{
return (ctx, (T)this);
}
}
public record class FSM<T, CTX, ST> : imm.Recorded<FSM<T, CTX, ST>>
where T : FSM<T, CTX, ST>
where CTX : Context
where ST : State<ST, CTX>
{
public CTX Context { get; private set; }
public ST State { get; private set; }
public FSM( CTX context, ST stStart )
{
Context = context;
State = stStart;
}
public FSM<T, CTX, ST> Transition(ST newState)
{
var (newOldCTX, oldState) = State.onExit(Context, newState);
var (newCTX, storeState) = newState.onEnter(newOldCTX, oldState);
return this with
{
Context = newCTX,
State = storeState,
};
}
}