Chip Salzenberg writes:
According to Ken Fox:
Overlapping metadata is a problem though.
Not in this area, AFAIK.
How about this text:
hello<foot><foot>fu</foot>bar</foot>
which (could) become:
# 0123456789
$s = "hellofubar";
meta($s, 5, 2) = 'foot';
meta($s, 7, 3) = 'foot';
meta($s, 5, 0) = 'word break'; # otherwise \b fails!
meta($s, 7, 0) = 'word break';
Calling meta($s, 'foot') will return foot ABC. How should foot DEF
be fetched? It applies to the same offset. I think meta() should
always return a metadata stream (collection maybe?). (I'm assuming
that Topaz will have more built-in data types than Perl 5.) The
stream should include all matching metadata objects contained in the
range of the first metadata object found.
I favor streams over lists because we can mess around with the
semantics of streams whereas lists have to be compatible with Perl 5.
BTW, creating nested metadata isn't a problem with Chip's proposal.
The example above could also become:
# 012345
$s = "hello";
$t = "bar";
meta($t, 0, 0) = { name => 'foot', data => "fu" };
meta($s, 5, 0) = { name => 'foot', data => $t };
To fetch the nested foot, just say:
meta(meta($s, 'foot')->{data}, 'foot');
- Ken
--
Ken Fox, kfox(_at_)ford(_dot_)com, (313)59-44794
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