Subject: Re: tab leaders
From: Paul Rohr (paul@abisource.com)
Date: Sat Dec 11 1999 - 15:07:25 CST
At 12:07 PM 12/11/99 -0600, Stephen Hack wrote:
>Is there any mechanism to save tab leaders in Abiword yet? I know there's no
>layout code or editing code (in the CVS, that is).
As mentioned in the POW, the major issue here is to decide how to extend the
syntax of the tabstops property to also indicate which optional leader
character should be used. Once that's done, adding another member variable
to fl_TabStop() will be easy.
Like all properties, the values are automatically persisted to the file
format. The only code which needs to change is the UI and formatter stuff
which reads and writes values to/from that property.
Does anyone have a preferred syntax for this? The current tabstops syntax
is something like the following:
tabstops:4.5000in/R,0.5625in/L,2.3750in/C
Basically, extending this syntax is an exercise in reliable parsing, so the
usual questions apply:
1. Do we need to support arbitrary leader characters, or just a small fixed
set? The latter is obviously easier, but is it enough?
2. What are the relevant syntactic limitations of CSS here? For example,
commas, colons, and semicolons all have semantic significance already.
3. More specifically, dashes, pluses and periods already have semantic
significance while parsing dimensions.
4. Is there another text-based syntax we can use as a model? For example,
how does RTF handle this problem?
5. Are there any other models in our existing syntax we could use? For
example, we can optionally specify "at least" semantics for line-height.
Will that suffixing trick work as well here?
6. When considering multiple design alternatives, is one easier to parse
reliably? Likewise, are any of the alternatives more human-readable?
Since we'll want to maintain backward compatibility with whatever we choose
here, I'd appreciate design feedback from anyone on the list with relevant
expertise.
>The tabs dialog is coming along nicely. Hopefully it'll be check in this
>weekend. (Possibly w/ leader editing support).
Looking forward to it.
Paul
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