Re: How does XML limit "the range of implementation decisions that must be automatically made"?

On Thu, Jun 23, 2022 at 5:09 PM Stephen D Green <[email protected]>
wrote:

The SQL is declarative, and non-procedural


This is a widespread myth.   SQL is an imperative language whose domain is
(mostly) relations rather than lower-level objects.  It is only
"declarative" in the sense that C is declarative: you tell the compiler
what you want done, and it chooses an execution plan for doing it, namely a
machine language program.

As for "procedural", it seems nowadays to be a synonym for "imperative".

Isn't all
> declarative, 'non-procedural' code usually actually turned into
> something procedural behind the scenes?


Yes, if it is compiled; no if it is interpreted.  This distinction is
meaningful but relative: languages are in all cases compiled into something
lower-level which is then interpreted, whether by hardware or software.  We
call an implementation an interpreter if it does only a small amount of
compiling; we call it a compiler if the interpreter is hardware or very low
level.


> Isn't declarative,
> 'non-procedural' code actually an illusion, wrapping procedural code
> under the hood - smoke and mirrors?


On modern pipelined CPU the so-called "machine language" is also smoke and
mirrors.  "You don't fool _me_, young man.  It's turtles all the way down."


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