From: Daniel Carrera <dcarrera@...>
Date: 2004-01-23T03:34:27+09:00
Subject: BibTeX parser

Hi all,

I have a difficult problem and I need some smart people to give me a hand.  
So I knew where to go for that. :)

I'm trying to figure out how to write a parser fo BibTeX files.  It's not 
easy.  A single BibTeX entry might look like this:

@BOOK{texbook,
    author    = "Donald O'brian",
    title     = "The {{\TeX}book}",
    publisher = 'Addison-Wesley',
    year      = 1984,
    key       = {Don's key}
}


I think you can see the problem.  

There is a nested collection of {squigly} brackers, as well as "double 
quotes" and 'single quotes'.  I'm not sure, either how to represent this 
structure, nor how to parse it.


If I only had to deal with {brackets} I could use an n-ary tree.  And to 
parse it, I would start with one node, move one character at a time.
Every time I see a { I'd make a new node.  Every time I saw a } I would 
come back up.


Now, when you and "double" quotes, the problem becomes more complicated, 
but doable.  I could first extract all the quotes and use an array where 
quoted and non-qutoed text alternates (for instance) and then parse using 
the brackets to make an n-ary tree.


But if I have 'single' quotes also, things can get very complicated.  I 
will have to deal with thigns like:

   {Dan's book}

and

   "O'brian"

And at this point I am truly at a loss.


I hope one of the more experienced programmers here can offer some 
insight.

Thanks a lot,
-- 
Daniel Carrera | No trees were harmed in the generation of this  e-mail.
PhD student.   | A significant number of electrons were, however, severely 
Math Dept. UMD | inconvenienced.