[tex-k] FYI: CWEB problems with PDF bookmarks

Julian Gilbey julian at d-and-j.net
Sun May 22 21:48:10 CEST 2016

On Mon, May 16, 2016 at 04:44:41PM +0200, Andreas Scherer wrote:
> To whom it may concern:
> I have been approached by mail that the set of PDF-related macros in 
> cwebmac.tex (originating from cweb 3.61 as of fall 2000) produces problems 
> with PDF bookmarks for sources and change files when "\let\maybe=\iffalse" is 
> set, so that only "changed" sections are actually printed.

Hello Andreas,

I replied to the original email author as follows:


The macros are not particularly robust: they were built by Don Knuth (the
original WEB macros) and then modified by Silvio Levy for CWEB, and
were designed to be good enough for most practical purposes.

The PDF features were added later by Silvio Levy, as far as I am
aware.  There seems to be no care taken to ensure that bookmarks work
correctly when only outputting changed sections; search the
cwebmac.tex file for the occurrence of the string "num" to see where
the PDF annotations are created and used.

It looks like it would be a significant pain to fix it for this
somewhat unusual use case, and would require some major redesign, so I
doubt anyone would be likely to do the needed work.


I had a quick think about what would be needed to fix it, and realised
that it would require a major code rewrite, which is probably not
worth it for this use case.


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