Yes, I think he finds a DSL useful for that reason: each place where flow of code diverges (FOR, IF) is recorded and serves as the identity of the entire execution path.
The differential execution approach is to "diff" the GUI by "diff"ing the program's control flow. As opposed to something like React where we're diffing the virtual-DOM output of the render().
During a GUI update the program is run comparing it's new control flow with the prior run. So for example on an IF statement, if the prior execution took branch A but the new run takes branch B, then we need to run branch A again in "erase" mode to erase everything created by branch A, then run branch B to create the new state.
The differential execution approach is to "diff" the GUI by "diff"ing the program's control flow. As opposed to something like React where we're diffing the virtual-DOM output of the render().
During a GUI update the program is run comparing it's new control flow with the prior run. So for example on an IF statement, if the prior execution took branch A but the new run takes branch B, then we need to run branch A again in "erase" mode to erase everything created by branch A, then run branch B to create the new state.