Re: customizing coverage

[Ludovic Courtès]

Hi!

Thien-Thi Nguyen <address@hidden> skribis:

> () address@hidden (Ludovic Courtès)
> () Fri, 20 Jan 2012 22:17:51 +0100
>
>    So presumably, what you show above shouldn’t interfere badly, and in
>    fact shouldn’t make any difference.
>
> Good.
>
> Is that URL stable?  I'd like to add a blurb in HACKING re "how to
> add --enable-coverage to configure" (unless you beat me to it).

Yes, it’s fairly stable (it points to the Nixpkgs SVN repo.)

Note that ‘coverageAnalysis’ is documented in Hydra’s manual,
<http://hydra.nixos.org/job/hydra/trunk/tarball/latest/download-by-type/doc/manual>.

> It seems to me ‘X = TRANSFORM (X)’ is like the binding clause of a
> ‘let’ binding block, rather than that of ‘let*’.  Do i misunderstand?

There are two different things:

  1. local variables introduced by the ‘let’ form (which roughly
     corresponds to Scheme’s ‘letrec*’);

  2. attributes within attribute sets.

Attribute sets are a dictionary type (sort-of like vhashes in Guile),
associating symbols with values:

  { a = 1; b = 2; }

There are also recursive attribute sets, where values can refer to other
attributes of the set:

  rec { a = 1; b = a; }

The manual of Nix contains more details, see
<http://hydra.nixos.org/job/nix/trunk/tarball/latest/download/1/nix/manual.html>.

Thanks,
Ludo’.