Re: [Re: Re: [naviserver-devel] ns_parseargs example]

[Zoran V. <zv...@ar...>]

Am 30.05.2005 um 12:23 schrieb Stephen Deasey:

>
> The other option is -eightbit:flag syntax.  It's not perfect, but it's
> better than nested lists and has ~5 years of usage in the ACS behind
> it.
>

Another try (I can't just let go) ...

I do not see much sense in trying to keep the Tcl argument list
format under all costs. Give me a good reason why we should do that?
Anyways, we are about to define a new "proc"-type of command
(ns_proc) aren't we? What is the sense then to force ourselves
to the old format?

Why don't we *extend* Tcl-proc arg-treatment like this:

    {name typecheck ?default_value?}

This is *not* Tcl-proc compatible but *is* in the spirit of
the language. The "typecheck" above can/will be definitely
a list of one or more elements, depending on the check itself.
The typecheck is *forced*. You must give a type. If you need
no checking at all use "string" which will cover all possiblities.
By *forcing* the type-check, many of the programming
errors and double-checks in the procedure itself can be saved.

Also, all people needing no extra checking can always use plain Tcl-proc
calls. Others who'd need checking would use exteneded ns_proc syntax.
This is pretty clear and I see no problems with that at all.

For example:
    ns_parseargs {{-retries int 0} {-blockcopy flag} {device string}  
args}

or
    ns_proc dosomething {{-retries int 0} {-blockcopy flag} {device  
string}} {
       # ...
    }

The most natural Tcl-way is to use lists. We've seen that the
desperate try to keep the Tcl-proc syntax leads to too complicated
nested lists which humans are not easily assembling.
So, this is a plain list which is easy to write and read by humans.

We can evolve typecheck over time to include more elaborate
tests, but a handful of those (string, int, flag, bool, list) are most
useful and complete for about all the needs I can think of
at the moment.

What is wrong with that (except that it perhaps does not follow
openacs model)?

Zoran