[Tile-dev] Tree API -- item identifiers

[Joe E. <jen...@fl...>]

Well, I tried switching to the form

    $tree insert $parent $index ...options ...

returning an integer item ID.  This didn't work out as
well as I thought it would.

Use cases where you want application-defined node IDs --
like the test suite -- really do become a lot more painful.
There's an odd asymmetry in that you *have* to name columns
but you *can't* name items.  The implementation and test suite
didn't really get any simpler, it just traded one set of special
cases for another one.

This form lacks discoverability: when you're playing with
the widget from an interactive wish prompt, you end up
saying things like:

    $tree insert 91 3 -text foo

Since item ids and indexes are both integers, this gets confusing.
The only real benefit is that it saves some memory [*].

So for now I've reverted to the BWidget form,

    $tree insert $index $parent $id ...options...

I'm going to try this next:

    $tree insert $parent $index ? -id $id ? ...options...

If "-id" isn't supplied, the widget will generate one
of the form "ixxxx", where the xes are hex digits.


--Joe English

  jen...@fl...

[*] I haven't bothered measuring, but: items currently take
10 words plus a hash table entry plus a TCL_STRING_KEY; with
integer IDs the last can be changed to a TCL_ONE_WORD_KEY
which is "free" with the hash entry.