Re: Can't compile hello world with cons plus

[Johan Holmberg]

On Fri, 17 May 2002, Steve Allan wrote:
>
> I'd like to convert my GNU make system to cons, but I need some of the
> features of Cons Plus.  Unfortunately, I seem to be having trouble getting
> cons plus to work. When I try to build 'Hello World' with cons plus, I get
> this message:
>
>   Error: File with unknown language,
>   Error: don't know how to produce an object file from
> 'file=HASH(0x259410c)'.
>
> Does this look familar to anyone?  The same source builds fine with plain
> Cons.   My build environment is:
> [...]
> Cons 2.2.0
> Cons-Plus-0.06
>

Sorry for this late answer (I've been on vacation).
I saw that you already  got an answer (ie. "too old Cons"),
but since I'm the author of Cons::Plus I still want to give my
explanation.

Cons::Plus is forced to use an "undocumented" part of the interfaces
in Cons (the 'cons::_Objects' method) to do it's job.

Somewhere after 2.2.0, this interface was changed (Steven couldn't
know that I was dependent on that interface; thats the whole point
of being "undocumented").

The change occured in RCS version 1.140 of "cons.pl".
Cons 2.2.0 is before this change (RCS version 1.129)
Cons 2.3.0 is after  this change (RCS version 1.161)

I have planned to make Cons::Plus "aware" of which "cons.pl" it is
used under, and complain if it is too old (I should probably
add this to the next version of Cons::Plus).

I choose not to try to be compatible with old versions of cons.pl
(perhaps I'm to lazy).

I think 2.2.0 is somewhat old by now (from 2000/11/16 it seems),
but I realize that it can be confusing that Cons::Plus doesn't work
with the latest "stable" version.

I'll think about this for later versions of Cons::Plus, but I think
it would be nice if a new "stable" version was produced, that wasn't
so old ...


/johan holmberg