[augeas-devel] Representing and setting a null key

[Matt Palmer]

I have a lens that is trying to parse a list of strings, which are a mix of
just values and key/value pairs, and I'd like to turn that into a list.  For
example:

append key=val something else foo=bar

Should turn into:

append/key val
append/(none)[1] something
append/(none)[2] else
append/foo bar

By leaving the key unspecified in the lens, I can produce this exact tree,
and that's cool (well, I'd like it if "something" and "else" were keys
rather than values, but I understand why that isn't practical).

There are two problems I'm stuck on, though:

1) How do I specify the null key in my parsing tests?  I've tried many
variations:

{ (none) = "something" }
{ = "something" }
{ (null) = "something" }
{ none = "something" }
{ "something" }

And so on.  Nothing I've thought up yet does the trick (most of them are
syntax errors, a few just do the wrong thing).

2) How do I represent the null key in my "set" commands?  A trailing slash
and using an index both fail:

set "/append/" "notsoempty"     => "garbage at end of path expression"
set "/append/[1]" "notsoempty"  => "empty name"

In case anyone's curious and hasn't worked it out, I'm writing a lens for
{pxe,iso,sys}linux files, which I'll release if I can ever get the bloody
thing working.

Any suggestions (either as to my direct problem, or alternate suggestions
for representing the data I have in a sane tree format) greatly appreciated.


-- 
Matt Palmer - Systems Administrator

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