Issue 87337 - sub/sup: do not force operators as non-objects
sub/sup: do not force operators as non-objects
Status: REOPENED
Product: Math
Classification: Application
Component: code
OOo 2.3.1
All All
: P3 trivial (vote)
: ---
Assigned To: AOO issues mailing list
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Depends on:
Blocks:
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Reported: 2008-03-22 16:21 UTC by macias
Modified: 2013-08-07 14:54 UTC (History)
3 users (show)

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Issue Type: ENHANCEMENT
Latest Confirmation on: ---
Developer Difficulty: ---


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Description macias 2008-03-22 16:21:30 UTC
This for example will not work:
sub 0

despite it makes sense. And I need to use it all the time in expressions like 
this one:

P(AB  mline sub 0)

(again it does not work). Workaround -- insert empty object:
P(AB  mline "" sub 0)

but it would be really useful to simply write what you mean. In latex you just 
type:
P(AB|_2)
and that's it -- no fake objects to make parser happy.

Bottom line -- if user needs to use sup/sub tags, just let him/her do it, do 
not check if there is an reference object for it.
Comment 1 troodon 2008-03-22 19:49:23 UTC
Confirming with 2.4. I think the easier fix for this is to consider mline as a
valid reference object. Please note that expressions like

a divides^c_d b
a nsupset^c_d b
a equiv^c_d b
a parallel^c_d b
a divides^c_d b

are allowed and so should be a mline^c_d b.
Comment 2 eric.bachard 2008-03-22 21:25:30 UTC
CC for me

Comment 3 michael.ruess 2008-03-27 10:08:23 UTC
MRU->TL: could be a useful change for the future. I think it should be allowed
to use the "sub x" expression anywhere the user wants. There are some more
situations than just using as index.
Comment 4 thomas.lange 2008-03-27 12:23:52 UTC
The problem with this is that the parser needs to decide where the subscript is
placed on way or the other.

The two choice that immediately come two mind are
  left ( a over b _ 2 right ) newline
  left ( a over b "" _ 2 right ) newline 
And it becomes worse if the same idea is applied to left subscripts as (and it
should be for sake of common overall behavior)
  left ( a over b _ lsub right ) newline
  left ( a over b "" _ lsub right ) newline 

There is no way a mere parser can decide what the users intend was when writing it. 

Also such a change will be incompatible with existing documents that might have
such constructs in use. You can't just have the formula
  left ( a over b right ) _2 newline
look differently from one version to another. 
Currently the "2" is rendered at the bottom of the right brace where according
to your proposal it should be rendered like
  left ( a over b right ) {}_2 newline
Thus there would be import and export filter required as well.

Maybe(!) it is possible to introduce some special rules to handle the case
better but a simple rule with no exception is usually preferable to more more
complex rules that have exception.

Overall: No, this is not going to be changed.
Especially not since there is a good concept that makes it clear to the parser
and reader(!) which way the user wants the formula to be rendered. It is the
very same construct that can also be used in TeX. 
And that is already almost what you did. The expected way to do this is using
empty groups. E.g:
  P(AB |{}_0)
Comment 5 macias 2008-03-27 13:05:26 UTC
> It is the very same construct that can also be used in TeX. 

Ooo:
P(AB mline {} _0)

Latex:
P(AB|_0)

The problem is -- you can make OOo as the latex competitor, or you can make 
every piece a bit more complex than latex (for reason unknown), but then latex 
will easily beat OOo.

In this case it "just" 7 keystrokes less in favor of latex. And think about 
people with RSI or handicapped, for them it is not "just" 7 keystrokes, less 
or more. And this is just _one_ _simply_ equation.

Latex parser can decide what object is on the left, so I guess it is 
technically possible.

I am reopening this issue for reconsideration -- it is all if you want good 
theory of parsing, or great Ooo.

I rephrase the wish maybe a bit -- do not insist that operators are not 
objects (case of sub and sup).
Comment 6 macias 2008-03-27 13:08:40 UTC
PS. Sorry, missed the counting -- it is _8_ keystrokes difference. And the 
equation in latex takes 11 keystrokes (on my layout 9). So Ooo makes almost 
the double of it.