texinfo - wrap long lines in code

Question

I found a hint from Karl Berry written 4 years ago about how to get line wrapping in code samples, in texi2pdf output. I demonstrate that solution below. However, it would be interesting to know if there is a way to do this without requiring hand-tuning of the expressions that are being printed.

One possible work-around that occurred to me is to do the hand-tweaking as needed and wrap that in @ifpdf tags. But that seems to be explicitly not possible.

At present, Texinfo does not provide ‘@ifpdf’ or ‘@pdf’ commands as for the other output formats, since PDF documents contain many internal low-level offsets and references that would be hard or impossible to get right at the Texinfo source level.

\input texinfo   @c -*-texinfo-*-      
@c %**start of header
@setfilename longline.info
@settitle Long Line Sample
@c %**end of header

@node    Top
@chapter Long line example

Here is an example of a code block, it is formatted using a pair of matching @code{@@example} and @code{@@end example} tags.

@example
(["lessfrequentword" java.lang.string]
["mostfrequentword" java.lang.string]
["wordstupleswithfrequency" 
#<parameterizedtypeimpl java.util.arraylist<java.lang.string[]>>]
["words" #<parameterizedtypeimpl
 java.util.arraylist<ccg.flow.processnodes.text.retrievers.dictionary.dictionaryitem>>])
@end example

As you can see, there is no linewrapping.  What I would like is something that looks more like this:

@quotation
@t{(["lessfrequentword" java.lang.string]}@*
@t{["mostfrequentword" java.lang.string]}@*
@t{["wordstupleswithfrequency"}@*
@t{#<parameterizedtypeimpl java.util.arraylist<java.lang.string[]>>]}@*
@t{["words" #<parameterizedtypeimpl}@*
@t{ java.util.arraylist<ccg.flow.processnodes.text.retrievers.dictionary. dictionaryitem>>])}@*
@end quotation

But ideally without the need to hand-tweak the text (note extra space introduced in the
second listing in particular).

@bye

Answer 1

something like this might be a start

Start the file

\input texinfo   @c -*-texinfo-*-
@iftex
@input texinfoextras
@end iftex

then compiling (e.g. for Info) with

makeinfo --no-iftex texinfo.texi

to hide the input command from this processor.

For processing with texi2pdf, a sensible texinfoextras.tex could be

@catcode`@\=0
\let\oldexample\example
{
\gdef\example{\oldexample
\relax
\catcode46=\active
\def\normaldot{\string.\hfil\penalty0\hfilneg}}
}
@catcode`@\=13

which allows line wrapping on . resulting in