On Fri, Sep 23, 2011 at 4:37 PM, Pete <p...@mollysrevenge.com> wrote:
> Thanks for such a clear explanation of what is involved, Andre! > Don't take it as the platonic truth... that was my approach only and what I've seen thru the years. I bet there will be someone that will simply prove me wrong. Cheers and thanks for the kind words. andre > Pete > Molly's Revenge <http://www.mollysrevenge.com> > > > > > On Fri, Sep 23, 2011 at 12:13 PM, Andre Garzia <an...@andregarzia.com > >wrote: > > > Folks, > > > > Speaking as someone who actually (tried to) build lots LC to Web tools I > > must say that the challenge is not rendering the controls or converting > the > > language to javascript. That is not where the main issue lies. To convert > > LC > > to the Web, you would need what I call an "LiveCode Kernel" implemented > in > > Javascript. This would be basically a reimplementation of the features we > > have in the engine such as message path, all the commands, all the > > functions, all the externals, all the controls, all of everything, in > > javascript. someting like: > > > > livecode.js > > > > Now, a translation process would begin by exporting the stackfile format > to > > a json structure with all the properties and ownerships so that in the > end > > you have a complete translation of all the data that is in the stackfile > to > > a format that can be manipulated by javascript. With this json alone, you > > would be able to render the user interface but the scripts would require > > more work. > > > > Multiple steps would be needed to convert the scripts of the stack. They > > would be parsed into an AST of sorts, a graph or some storage medium that > > we > > could use to keep our representation of the script. This AST-like thing > > would then be exported to unoptimized javascript where all the LiveCode > > commands and functions are just wrapped in javascript calls so a script > > like: > > > > get totalTime > > add 1 to it > > put it into field "total" > > > > would be converted to: > > > > lc.env.it = totalTime; > > lc.env.it += 1; > > lcSetObjectProperty(lcObjectReference("field","total"), "text", > lc.env.it > > ); > > > > You can see that there is no inteligence, it is a direct translation > > changing all that would be LiveCode commands to javascript wrappers. a > > global structure in the form of "lc.env.*" holds all the globals and > > special > > variables. A helper function lcSetObjectProperty() is used to set any > > object > > property using three parameters - the object reference, the property, the > > value. Another helper function picks an object type and a name and > returns > > the reference that is used in the lcSetObjectProperty(); > > > > We're not translating LiveCode script to idiomatic Javascript, we're > > wrapping LiveCode semantics in a JavaScript syntax. This would be very > slow > > but it would not be the hardest thing to build. Once you have a way to > pick > > an alternative stackfile representation like a JSON file and you have all > > the engine features wrapped in your own javascript little kernel, you can > > convert stacks to the web. > > > > What many projects that boost their features as RAD tools for the web are > > doing is something different. Instead of translating their stuff to > > HTML+CSS+JS, what they do is wrap around the native program. They create > a > > virtual screen on the browser where the output that would usually go to > X11 > > or something similar is sent to the browser in a CANVAS tag or SVG or > JPG. > > The raw mouse input such as coordinates and button status are constantly > > sent back to the server along with the keyboard status. The server > maintain > > different client states for each connected user allowing the software to > > mimic it being run as different instances. This can be accomplished with > > closures and continuations. In this way, there is no conversion at all, > you > > have a wrapper that pipes output to the browser and pushes browser input > > events to the server. All the logic and inteligence is on the server, > there > > is nothing business related on the browser. > > > > This approach might sound more complicated but it is actually easier. > Just > > google for GTK on the Web and you will see a GTK adapter that just do > that. > > We can adopt that approach with LiveCode because we don't have > multitasking > > or closures or continuations so the user state management would be really > > hard. > > > > The previous approach of reimplementing the engine in javascript and > > passing > > a stackfile representation around brings the logic and inteligence back > to > > the browser and the server has no dealing with it anymore. It is a harder > > approach but it can be done. I started coding this during that Apple > > License > > fiasco we had where they prohibited all the non-objc languages on the > > appStore. I called the project RevImpossible and set a very slow pace. > When > > apple reverted their license, I saw no use in trying to reimplement > > something that is so complex (it would take me years and a lot of smart > > people with me). I shifted RevImpossible to another focus, it still > > converts > > the visuals of stacks to the web but my focus is not the scripts anymore > > but > > a quick way to prototype websites using RevIgniter. > > > > My two cents > > PS: REALStudio Web thing appears to use FastCGI. I demoed a Revolution > > FastCGI library during RevConWest a long time ago... > > _______________________________________________ > > use-livecode mailing list > > use-livecode@lists.runrev.com > > Please visit this url to subscribe, unsubscribe and manage your > > subscription preferences: > > http://lists.runrev.com/mailman/listinfo/use-livecode > > > > > _______________________________________________ > use-livecode mailing list > use-livecode@lists.runrev.com > Please visit this url to subscribe, unsubscribe and manage your > subscription preferences: > http://lists.runrev.com/mailman/listinfo/use-livecode > -- http://www.andregarzia.com All We Do Is Code. _______________________________________________ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode
