Re: New command eval.

[Andrey Borzenkov]

В Sat, 11 May 2013 17:07:19 -0700
Seth Goldberg <address@hidden> пишет:

> Hi,
> 
>   What about the feature environment variable to allow dynamic detection of 
> this enhancement?
> 

That really does not scale. Commands come and go. What about single
command "has" (or probably better "implements") as in

implements --command eval|testspeed|...
implements --crypto_algorithm sha256|...
implements --network_protocol http|tftp|ipv6|...

Command "implements" itself may be instantiated under
fetature_201_final (or whatever next version is).

It probably could even be extended to feature test of single commands,
like

implements --command menuentry --feature id


Note that in this specific case (eval) this probably is not useful at
all. If you want to test whether this command is present, you
presumably are going to write alternative implementation without eval.
In this case why bother to test in the first place?