Re: Dynamic functions

[Poul-Erik Andreasen <poulerik@pea.dk>]

Dmitry A. Kazakov wrote:
> On Fri, 10 Aug 2007 08:54:57 +0200, in comp.lang.ada you wrote:
> 
>> Poul-Erik Andreasen wrote:
>>
>>> How is the best way to make a representation of a function/algorithm
>>> wich can bee setup at runtime in Ada.
>> Is there any reason that you cannot convert the function to Ada, write
>> it to a file, compile it to a plug-in/DLL/shared library, and then
>> load the plug-in/DLL/shared library?
> 
> Yup, this is how MatLab and many other similar languages do, if you really
> need to *program* (as opposed to draw (:-))  something...
>  
>> The complication is that it requires an Ada compiler on the running
>> system, but the benefit is pretty fast execution.
> 
> ?
> 
> Execution includes elaboration of the code. In your case elaboration would
> mean to call the compiler, to link the DLL, to load the DLL. How frequent
> the given function F will be called per run? If you are not going to design
> some image rendering/processing system with millions of calls per function,
> it probably will not pay off.

In my case wee are in fact talking about  several million calls per 
function. Jacob have bee proposing this model to me before, but i find i 
a bit to cumbersome. By the way it is not images it is timeseries

> Other potential issues:
> 
> 1. You will need a lot of free system resources to be able to run the
> compiler/linker in parallel to your program, free memory and disk space.
> 
> 2. The response time (from request to execute F to its start) will be
> awful.
> 
> 3. You will need to manage files (lots of) and other environmental stuff.
> Deployment, integration etc might turn difficult.

This is my main issue
> 
> 4. DLL interface does not know Ada. Exporting complex data types and
> objects of from a dynamically loaded DLL could be difficult.
> 
> 5. DLL handling stuff is non-portable.
> 
This could also become an issue.