Re: Registries

At 19:07 2003-07-13, David Abrahams wrote:
>Daniel Wallin <[email protected]> writes:
> > No, lua doesn't share python's concept of modules.
>
>OK, downloading lua, reading docs...
>
>Hmm, Lua is both cool (nice simple foundation, nice anonymous
>functions,...) and deeply disturbing.
>
><rant>
>
>The designers seem to have no problem letting coding errors pass
>silently.  I can't believe they made global variables the default and
>don't require an arity match for tuple assignment!  Ick, fully-closed
>ranges in for loops and 1-based indexing (how is that good in a
>language designed to interface with C/C++?)!  Ick, 'n' has special
>status as a table key!

By "tuple assignment" you mean multiple return values? It can be quite
convenient sometimes to not have arity checking there, although I agree
that it can result in coding errors getting passed by.
I agree with your other rants, global default in particular is disturbing.

>[and why can't I seem to call getn from the interactive interpreter?
>     $ lua
>     Lua 5.0  Copyright (C) 1994-2003 Tecgraf, PUC-Rio
>     > print(getn)
>     nil
>]

It should be "table.getn".

    > ./lua
    Lua 5.0  Copyright (C) 1994-2003 Tecgraf, PUC-Rio
    > print(table.getn)
    function: 0xa042350

>Hmm, the first draft of "Programming in Lua" seems wildly outdated.
>Maybe some of these problems are fixed?  No upvalues anymore, for
>example!  How do you learn this language these days?

Well, lua isn't as complex as python so it isn't that hard learning it, so 
I guess
you just read the reference manual and learn by trying. :)

> >> > When using multiple language bindings in the same system, it's
> >> > probably desirable to keep the cast-graph's separated.
> >>
> >>Why?  I can't see any good reason for that.
> >
> > You are right, there are no good reasons. I was confused.
> > All inheritance code can be shared directly.
>
>I was talking about the data structures.

Me too, but in my second post I for some reason decided to confuse you by
writing 'code' instead of 'graphs'. :)

>Given peoples' tendency to
>stick everything in the global namespace in C++, I guess we ought to
>consider having a separate cast graph for each group of interacting
>extension modules.  By "interacting" I mean that two extension modules
>manipulate some of the same C++ types and use them in their function
>interfaces.

Why? Do you mean because of type_info::name() comparing?
In that case we have the same problem of unique ID's with
the conversion registry as well.

>One question I have is, "how does a user say that this extension
>module interacts with these others, and what, precisely, does it mean
>internally?"

If the problem is the unique id's; do we really need to care about it?

---
Daniel Wallin



-------------------------------------------------------
This SF.Net email sponsored by: Parasoft
Error proof Web apps, automate testing & more.
Download & eval WebKing and get a free book.
www.parasoft.com/bulletproofapps1