I believe this is caused by the Composer and Transformer working slightly
differently.
Basically by placing the insert after the delete the Composer is encoding
non-existent information about the location of the insert, namely that it was
inserted after the location of the delete.
Whereas the Transformer receiving `c1` then `c2` will be working on the
assumption that the 'c' was inserted to the left of the delete location.
So based on this one example I think having the Composer place inserts that
occur after deletes to the left of the deletes would work, however I think this
could break depending on if the composition is happening on the server side or
the client side.
--
Wim Looman
ghostundersc...@gmail.com
On 5/03/2011, at 9:43 PM, Joseph Gentle wrote:
> On Sat, Mar 5, 2011 at 6:45 PM, Joseph Gentle <jose...@gmail.com> wrote:
>> s = insert: 's', skip: 1
>> c1 = delete: 'x'
>> c2 = insert: 'c'
>>
>>
>> // Make println() usable.
>> DocOpScrub.setShouldScrubByDefault(false);
>>
>> DocOp s = new DocOpBuilder().characters("s").retain(1).build();
>>
>> DocOp c1 = new DocOpBuilder().deleteCharacters("x").build();
>> DocOp c2 = new DocOpBuilder().characters("c").build();
>>
>> DocOp cc = Composer.compose(c1, c2);
>>
>> // s_ = s T c1
>> DocOp s_ = Transformer.transform(c1, s).serverOp();
>> // s__ = s T c1 T c2
>> DocOp s__ = Transformer.transform(c2, s_).serverOp();
>>
>> // cc = c1 + c2
>> System.out.println("cc: " + cc);
>> // scc_ = s T (c1 + c2)
>> DocOp scc_ = Transformer.transform(cc, s).serverOp();
>>
>> // s__ and scc_ are different!
>> System.out.println("s__: " + s__);
>> System.out.println("scc_: " + scc_);
>> System.out.println();
>>
>> // ... And not just different syntactically. They're different
>> semantically.
>> DocOp doc1 = Composer.compose(ImmutableList.of(new
>> DocOpBuilder().characters("x").build(), c1, c2, s__));
>> System.out.println("doc1: " + doc1);
>>
>> DocOp doc2 = Composer.compose(ImmutableList.of(new
>> DocOpBuilder().characters("x").build(), cc, scc_));
>> System.out.println("doc2: " + doc2);
>>
>
> How rude of me!
>
> Output:
>
> cc: [--"x"; ++"c"; ]
>
> s__: [__1; ++"s"; ]
> scc_: [++"s"; __1; ]
> ^----- You would expect these last two to be equivalent
>
> doc1: [++"cs"; ]
> doc2: [++"sc"; ]
> ^----- .... and these to be identical.
