RE: runtine instanciation

[Dmitry A.Kazakov <mailbox@dmitry-kazakov.de>]

Robert C. Leif wrote:

> From: Bob Leif
> To: Dmitry Kazakov et al.
> I suspect that in many cases there is a very straightforward approach to
> accomplish the equivalent of runtime instantiation. In my own work on
> the creation of a new bioinformatics standard, CytometryML, I have a
> requirement to create an array of records, which can have up to 15
> fields. Each of the data types for the fields (parameters) will be
> represented by a compiled package with a complete set of specific
> operations. However, the user (customer) at runtime will have the
> prerogative of selecting from 1 to 15 of these parameters to include in
> the record. Fortunately, this is directly analogous to the creation of
> the data type in a database. It does NOT have to occur instantaneously.
> Conceivably, the user could wait about a minute for this to occur. I
> would like to be able to compile and link the instantiation of the
> record and the array. Parenthetically, I am quite willing, if need be,
> to precompile 15 generic packages of records, which have from one to
> fifteen fields and instantiate only one of them. The 15 generic records
> perhaps could also be included in one package.
> 
> Another similar problem, is to create a calculation program in Ada that
> is very general for evaluating a mathematical expression. If the
> expression can be converted to an Ada function, why not just compile it?
> 
> I believe Rational and DEC had incremental compilers. Could this
> facility be made available, even in a space inefficient form, in one of
> the Ada 95 compilers? This approach has a significant potential
> commercial benefit for the vendors. It would require a runtime version
> of their compilers, which could be licensed for a fee to be ultimately
> paid by the end users of the program.
> 
> Before any of the real-time enthusiasts become upset by this proposal,
> please remember, that this is not to be applied to the run-time
> operations of mission critical applications where execution time and
> scheduling are important.

Well, if performance is not an issue, why not to use class-wide objects 
instead of genericity? Doing so you would not need to instantiate anything. 
In fact no automatic instantiation would help if the types are unknown in 
advance. A brute force, like an integrated compiler might help, but I think 
it would be better to advance ADT to solve problems like that. [ Those who 
disagree may just switch to SmallTalk. (:-)) ]

-- 
Regards,
Dmitry Kazakov
www.dmitry-kazakov.de