[Laszlo-dev] Dynamic libraries

[Andrew Wooldridge]

Hmm how about DLib or DyLi (Dilly) 
:)

I cant wait to see this in action.  This was supposed to be a big
feature for XUL/Mozilla, but I dont thing it ever has (yet) been
implemented.  Is this a parity feature with Flex?

-Andrew




On Fri, 7 Jan 2005 11:03:23 -0500, Oliver Steele
<steele at laszlosystems.com> wrote:
> One of the new features for LPS 3.0 is the dynamically loaded library,
> or dynamic library.  A dynamic library is a library that can be loaded
> after the main application execution file has loaded.  The initial goal
> for dynamic libraries is to reduce the initial download size of a
> Laszlo application, by deferring bandwidth costs until an optional
> feature of the application is actually used, or at least until the user
> has had time to interact with the initial screen.  Some non-goals for
> the initial implementation are shared libraries (where the same
> dynamically loaded library execution file can be be shared among
> multiple applications), binary distribution (where a library author can
> distribute a Laszlo library without distributing source code), and
> namespaces (where two libraries can define entities with the same name,
> without collision).  It is intended that the initial version of dynamic
> libraries be forwards compatible with these features, but, in the
> interests of implementation time, the initial version will not
> implement them.
> 
> LPS 2.x, for comparison, has static libraries, which use the <library>
> element to define the library, and the <include> element to include it
> in an application (or another library).  Static libraries support
> source code organization, team workflow, and source re-use, but they
> don't have any effect, versus the alternate strategy of putting
> everything in one big source file, on the executable file: a program
> that includes a static library is equivalent, to the compiler, to a
> program that has had the library source code textually inserted at the
> point of the <include> element.
> 
> Ideally, a dynamic library can contain anything that today's static
> library contains: class, instance, dataset, resource, and font
> definitions, as well as <script> blocks.  In practice, the Flash
> implementation of Laszlo may have some limits which Laszlo inherits
> from the limits of the Flash file format and execution engine.  We'll
> be exploring this over the next week; this message is intended partly
> to set the context for some of the discussions exploring those limits.
> 
> I'll send out a concrete proposal for the dynamic library syntax in the
> coming week.  Henry Minsky is implementing a draft of the syntax, and a
> limited provisional implementation is available in the 3.0b1 release
> (so you'll be able to try it out as soon as I tell you what it is :-).
> 
> Something we haven't decided yet is the name for dynamic libraries.
> I've been calling them dynamic libraries, short for dynamically loaded
> libraries, in this message, but that's a provisional name as well.
> It's unlikely that we'll call them "dynamically loaded libraries (DLL)"
> because that name has picked up some negative connotations over the
> past decade.  (These are connotations that I'm now learning to
> associate with the term "jar file", by the way, but we can get into
> that separately...)  "Dynamic library" is perhaps more accurate anyway,
> since it is likely that the location of the library can be determined
> at runtime, as well as just its bits.  Other names that have been
> bandied about are "snippets", "runtime libraries", and "runtime loaded
> libraries".
> 
> I suppose one could throw "execution", "late", "lazy", and "deferred"
> into the mix.  "Deferred" would be consistent with the
> initstage="deferred" attribute of views and other LZX nodes, which has
> an analogous function at the instance (as opposed to the file) level.
> In fact, it might be desireable to allow both "late" libraries which
> loaded automatically, but after the main execution file has loaded, and
> "deferred" libraries, which are loaded upon request.
> 
> Comments appreciated, although there will be another chance when I post
> the syntax.
> 
> Best,
> Oliver
> 
> --
> Oliver Steele
> Chief Software Architect
> Laszlo Systems, Inc.
> 
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