Thanks for the clarification, I didn't about them. Now I need even more reading and thinking :)
> Le 18 mai 2015 à 22:23, Marc Fawzi <[email protected]> a écrit : > > Back to composability > > I read about stacked vs hierarchical FSMs and it looks like what you want is > a stacked one not a hierarchical one... Subgraphs dont have to be entangled > with the global graph > > Sent from my iPhone > >> On May 18, 2015, at 10:26 AM, Khalid Jebbari <[email protected]> >> wrote: >> >> I like how you break up the state machines, it has sense in web app. Page 1 >> has 2 widgets, page 2 has a form. Each widget/form can have a FSM associated >> with it, the higher level FSM knowing just the higher level state of all >> widget displayed. Mmmh... Interesting. >> >>> Le 18 mai 2015 à 19:13, Daniel Kersten <[email protected]> a écrit : >>> >>> From my understanding of it: >>> >>> Use higher level states and decouple them somewhat from the data. >>> >>> For example, games do have lots of dynamically changing data. In a modern >>> shooter you might have dozens of characters with positions, orientation, >>> velocity, health information, weapons, ammunition, etc all of which can be >>> constantly changing. And that's just taking the characters into account. >>> >>> I wouldn't go and build a state machine that enumerates all of the possible >>> transitions from a "twelve characters with done distribution of attributes >>> in this location moving in that direction" state. I'd break it down so that >>> each character has a high level state like "seeking powerup" or "running". >>> >>> Probably not a great example although it does illustrate that you might >>> have a hierarchy of state machines. In the game example, the highest level >>> might be something like "in play" or "paused" and the lowest might be an >>> each characters "firing weapon". >>> >>> In client side web app, you could say that each configuration of data is a >>> state (the re-frame readme mentions that you could think of the app-db like >>> this), but I think that's too fine grained to be useful. >>> >>> Instead I'd define higher level states (possibly in a hierarchy). I'd ask >>> myself, regardless of the data available, what are the logical states that >>> a user could be in and for each one, what are the actions that they can >>> perform (and what state does each action transition them to). >>> This could be as simple as pages and links, but with a rich single page >>> application it's more likely finer grained than that. Maybe what dialogs or >>> widgets are accessible. >>> >>> Again, you could then layer these into a hierarchy of state machines. >>> >>> One advantage of this is you always know what a user can do at any given >>> time because you can look at what state they're in. >>> >>> I think of FSM states as orthogonal to the data, not as the data itself. >>> The states dictate what data is accessible and what can be done to it; the >>> data doesn't dictate what state the application is in. >>> >>> I suppose terminology gets confusing, but this is the approach I'm toying >>> with. I'll see how that goes :) >>> >>> But yeah, needs more thinking. >>> >>> >>>> On Mon, 18 May 2015 16:55 Marc Fawzi <[email protected]> wrote: >>>> Games are ideal candidate for straight-forward FSM implementation since >>>> you normally download the data at game load time and from there on you >>>> have a *relatively* small set of states that can be transitioned between >>>> based in user input. You can even apply state minimization techniques to >>>> reduce the total number of states. >>>> >>>> But in a web app you are continuously grabbing data from the server and >>>> that data is generated based on not only user input but also the state of >>>> the server side database and that server generated data would modify UI >>>> side app state and you have to account for all possibilities so the total >>>> number of states could grow wildly if your UI is data driven (where the >>>> state of the UI depends on the data in non-trivial ways) but even if your >>>> UI state dependence on server data was a trivial relationship you could >>>> still end up with a huge state diagram for the simplest viable business >>>> app if you include templating the view as part of the UI FSM on top of >>>> business logic. You could segment your app into micro apps and that will >>>> help regardless of whether you're building the app as FSM or not. >>>> >>>> And what if the state transitions are probability driven? How many states >>>> will you end up having to chart? >>>> >>>> Not convinced YET... >>>> >>>> Sent from my iPhone >>>> >>>> > On May 18, 2015, at 6:57 AM, Sean Tempesta <[email protected]> >>>> > wrote: >>>> > >>>> > Hi Khalid. I found your topic interesting so I thought I'd chime in. >>>> > Regarding your comments on routing: >>>> > >>>> > So, under normal conditions, the initial URL sets the FSM in motion (as >>>> > an event). We could call this entry point a routing state. Afterward, >>>> > the state transitions are controlling the urls (not the other way >>>> > around), right? >>>> > >>>> > Outside of normal conditions (ie. people copying and pasting links into >>>> > random parts of the system), you also just send the url to the routing >>>> > state and then switch to a new state based on whatever rules and >>>> > definitions you've set. >>>> > >>>> > Or maybe I'm missing something. I haven't built an FSM in a while. :) >>>> > >>>> > Sean >>>> > >>>> >> On Monday, May 18, 2015 at 6:07:22 PM UTC+8, Khalid Jebbari wrote: >>>> >> Trying to push forward the discussion about Web UI with state machines. >>>> >> I came up with the following decomposition of the core components of a >>>> >> web application : >>>> >> >>>> >> - application state >>>> >> - application data >>>> >> - business logic >>>> >> - ui logic >>>> >> - event processing >>>> >> - presentation layer >>>> >> - routing >>>> >> >>>> >> In this schema, I think the application state is the real core, because >>>> >> every other components is directly related to it, at least if you use a >>>> >> state machine. I came up with the following model. >>>> >> >>>> >> - application data : related to application state because both can >>>> >> easily represented as data. If we want a web app that is completely >>>> >> state-driven (I want this, for debugging, testing and time-travel >>>> >> capabilities), simply merge the data and the state in the same data >>>> >> entity. >>>> >> >>>> >> - business logic/ui logic : in a state machine there's the notion of >>>> >> "actions" executed with each transition (where necessary). So the logic >>>> >> could just be executed by the state machine itself. >>>> >> >>>> >> - event processing : a state machine can be event-driven, and this a >>>> >> perfect match with a web app since the web (and any UI for that matter) >>>> >> is inherently event driven. So the event/input of the state machine >>>> >> could just match the event triggered by the user, as well as custom >>>> >> events if necessary. >>>> >> >>>> >> - presentation layer : simply display the current app-state as >>>> >> HTML/CSS. In the React.js model, it would simply mean updating the app >>>> >> state and letting React render everything. >>>> >> >>>> >> - routing : this is where stuff gets complicated in my mind. In a >>>> >> proper application, lot of state is derived from the URLs. But not all >>>> >> state, for instance whether a modal is displayed or not, or whether a >>>> >> form is validated client side or not isn't tied to a URL. Which tend to >>>> >> let me think that there's some kind of hierarchy in the state machine. >>>> >> The URLs could be represented as events as well in the state machine, >>>> >> but could happen at anytime, whereas other events and related >>>> >> transition depend on the current state in a state machine. So it's like >>>> >> you have a top-level state machine for URLs, and each URL has its own >>>> >> state machine for all interactions in the page. Maybe page-state >>>> >> machine could be refined in multiple levels state machines too, not >>>> >> sure about that. It seems like Hierarchical State Machine may help >>>> >> here, but I haven't studied the subject yet at all. >>>> >> >>>> >> What do you think ? >>>> > >>>> > -- >>>> > Note that posts from new members are moderated - please be patient with >>>> > your first post. >>>> > --- >>>> > You received this message because you are subscribed to the Google >>>> > Groups "ClojureScript" group. >>>> > To unsubscribe from this group and stop receiving emails from it, send >>>> > an email to [email protected]. >>>> > To post to this group, send email to [email protected]. >>>> > Visit this group at http://groups.google.com/group/clojurescript. >>>> >>>> -- >>>> Note that posts from new members are moderated - please be patient with >>>> your first post. >>>> --- >>>> You received this message because you are subscribed to the Google Groups >>>> "ClojureScript" group. >>>> To unsubscribe from this group and stop receiving emails from it, send an >>>> email to [email protected]. >>>> To post to this group, send email to [email protected]. >>>> Visit this group at http://groups.google.com/group/clojurescript. >>> >>> -- >>> Note that posts from new members are moderated - please be patient with >>> your first post. >>> --- >>> You received this message because you are subscribed to a topic in the >>> Google Groups "ClojureScript" group. >>> To unsubscribe from this topic, visit >>> https://groups.google.com/d/topic/clojurescript/7STtgK5QiIc/unsubscribe. >>> To unsubscribe from this group and all its topics, send an email to >>> [email protected]. >>> To post to this group, send email to [email protected]. >>> Visit this group at http://groups.google.com/group/clojurescript. >> -- >> Note that posts from new members are moderated - please be patient with your >> first post. >> --- >> You received this message because you are subscribed to the Google Groups >> "ClojureScript" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at http://groups.google.com/group/clojurescript. > -- > Note that posts from new members are moderated - please be patient with your > first post. > --- > You received this message because you are subscribed to a topic in the Google > Groups "ClojureScript" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/clojurescript/7STtgK5QiIc/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/clojurescript. -- Note that posts from new members are moderated - please be patient with your first post. --- You received this message because you are subscribed to the Google Groups "ClojureScript" group. 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