Re: How to check if a symbol has been defined?

[Valeriy E. Ushakov]

On Tue, Nov 25, 2003 at 20:58:12 +0300, flamasuta wrote:

> From: "flamasuta" <address@hidden>
> X-Diagnostic: Not on the accept list

Please, subscribe.  Posting to the list is restricted to subscribers
only.

[BTW, has *anything* been decided about the new hosting for the list?]


> Is it possible to check if a symbol has already been defined?
> 
> For example, in pseudo-code:
> if (symbol is defined) then
>    do that thing
> else
>    do another thing
> endif
> 
> Or, at least, is it possible to re-define a symbol (only if it is 
> currently undefined)?

No.  Lout is not a macro language.  Some examples of what you can do
can be found here:

http://snark.ptc.spbu.ru/~uwe/lout/essays/496.scoping.txt
http://snark.ptc.spbu.ru/~uwe/lout/essays/636.scoping.txt

SY, Uwe
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