Re: nested entries in a configuration file

[Drake Wilson <drake@...>]

Quoth "Henderson, Michael D" <michael.d.henderson@lmco.com>, on 2011-02-24 11:01:34 -0700:
> The configuration file looks like:
> 
> database {
>   entry { id = 'batch@raw'
>     ,dev  = account { host = 'rawdev' , name = 'batch01', instance = 'raw' }
>     ,test = account { host = 'rawtest', name = 'batch11', instance = 'raw' }
>     ,prod = account { host = 'rawprod', name = 'batch21', instance = 'raw' }
>   },
>   entry { id = 'batch@staging'
>     ,dev  = account { host = 'stgdev' , name = 'batch02', instance = 'staging' }
>     ,test = account { host = 'stgtest', name = 'batch12', instance = 'staging' }
>     ,prod = account { host = 'stgprod', name = 'batch22', instance = 'staging' }
>   },
> }

Note that trailing commas are allowed in Lua table constructors, so
the initial-comma idiom is unnecessary unless there's some reason for
it I haven't seen before.

Also, curried function calls can be nice for this sort of thing:

  foo 'bar' { baz = 'quux' }

is equivalent to:

  foo('bar')({ baz = 'quux' })

and then you can handle the arguments in functional style:

  function foo(bar)
    return function(t)
      return do_something_with(bar, t.baz, 'quuuux')
    end
  end

I wouldn't necessarily do that here; I'd just make the entry IDs into
keys.  But if you don't want to generate the top-level table in one
go, you can also have functions that add entries to existing tables,
say, then postprocess things.

I don't know whether there's some other element that you think is ugly
or hard to understand compared to the other example, but those seem to
be the main differences.

   ---> Drake Wilson