You're over generalizing me just a bit.
Thank you for clarifying.
What I'm saying is that each action has a time frame, and also spells out which specific rules exist for it.
Fair enough. One minor quibble: each action does not necessarily spell out ALL the rules for it, but the rules it does include are undoubtably...rules for it...!
So no, they don't have to be divisible for their effects to last until the effect ends.
Sure, but IF actions are indivisible, AND each action lasts until its effects end (specific for each action), THEN if an action's duration has not ended, no other action can be taken.
Attack specifies that you can move in-between attacks.
And if you take the view that the
reason you can move
during the Attack action between attacks is because it says so, this means that you
cannot move
during ANY action if the book
doesn't say so!
Note that the rule for the Attack action does
not give you permission to move between attacks! There is no mention of moving between attacks in the description of the Attack action on p192.
The reason we are certain that you
can move between attacks is because it says so on p.190 under Movement and Position under Breaking Up Your Move: Moving Between Attacks.
IF you take the view that you cannot move
during an action without a rule saying you
can (I am not of that opinion myself), then in order to move
during an action is if it says so under Breaking Up Your Move (it does not, except for the Attack action) OR it says so under the heading of that particular action.
Dash specifies that your move speed doubles, so the duration for it is the duration of your movement.
Agreed. However, it certainly does
not say that you can move
during this action! Therefore, with the previous assumption, you
cannot move until ALL your movement has been expended, nor can you take any other action until ALL your move has been expended. So, with those assumptions, if you Dash then you cannot move(!) and cannot take any other action!
Disengage specifies that you can move and that such moves do not provoke attacks.
No. It does
not say that you can move! It says that your movement doesn't provoke. It remains in effect until your movement is expended, but with the above assumption you are not
allowed to move
during the Disengage action because you have no written permission to do so! Not in the description of Disengage, not in the section on Breaking Up Your Move.
If we say that the actions are all instantaneous, but the effects last longer, then you end up with the ridiculous situation I described above. You can take the Disengage action, do a 1 second jig, and then stand stock still. A monster who was nowhere near you when you began your jig can rush up to you, attack you while you are standing stock still, and get disadvantage to the attack. That's just silly, but it's the result of treating all actions as being instantaneous.
I agree that this interpretation would lead to 'silly'. But this position (position 1) is not that you Dodge for a moment and then stop while getting the benefit for a period of time; the position is that 'taking the action' is an instantaneous game construct decision by the player which allows the character to do the things associated with that action for the specified time. So 'taking the Dodge action' is an instantaneous event at the game table which then means that the character can dodge incoming attacks from now until the start of their next turn.
To remind you:-
1) is the position that 'taking the action' is an instantaneous player decision at the table which allows the character to do the stuff for a period of time
2) is the position that 'taking the action' and 'doing the stuff' are one and the same with the same duration.
2a) follows that actions are divisible
2b) follows that actions are
not divisible
Which of these positions do you hold?
Now, this is my reading of how RAW works. How I personally would run things would be to allow bonus actions to be used when it seems reasonable. I would let the shove from Shield Master work after the first attack and not require the attack to end first. I would allow bonus actions to work while you are moving for disengage and dash.
I appreciate that, because in my view it is not possible to hold position 2b) AND the position that you cannot break up your move without text saying that you can! You
must 'houserule' at this point, because that interpretation of RAW is unplayable!
However, it is of no value to debate what our houserules are! We can only debate the RAW and our interpretations of it. For me, the very fact that position 2b) and 'cannot break up your move without permission' positions result in an unplayable game clearly demonstrates that those are incorrect interpretations of the RAW!
Nothing requires you to use all of your movement. The rogue could use the bonus action, move however much he wants to until he decides to stop, then attack.
Since he cannot move
during an action, he cannot move. This means that taking the Dash or Disengage action is totally pointless given those previous interpretations.
For me, all this clearly rules out both 2b) AND the 'cannot move during an action without permission' interpretations of the RAW.
This leaves us with the interpretation that you CAN move during an action that is itself a non-instantaneous event. The Movement Between Attacks section therefore is not something that gives permission, but is there to clarify that you CAN move between attacks in this new 5e system, unlike in 3e/Pathfinder.
It also means that either position 1) OR position 2a) must be true.