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Noweb

A lyx document that explains how to get Lyx 1.6.2 working with noweb 2.11b, because sadly notangle garbles the output, and so does noweave to a lesser degree.

1.  Goal

Generate sane C files and Latex documents from Lyx, suitable for use from a Makefile.

Sadly notangle is not able to un-lyx-ify lyx noweb documents, it requires Lyx to do TeX export, which Lyx can do:

lyx -e literate FILENAME.lyx

which produces FILENAME.tex

If noweb is used works on the .Lyx file, we find some problems:

In a code scrap, a newline is not used to signify a newline, these signify a newline:

\begin_inset Newline newline
\end_inset

notangle is also unable to un-escape backslashes in the code scrap, which come out as:

\backslash

notangles's -L mode is also broken and ruins the indentation included noweb blocks in the generated code, as well as interrupting multi-line #define's.

Noweave with Lyx also generates spoiled output, with << in the code becoming a guillemot (double chevron as a single character), the fact that chunk names fail if they have an underscore in the name; e.g. <<file_name.c>>

2.  Solution

Some awk scripts to fixup notangle output and some sed filters to fixup the weave output.

3.  Files

I don't have access to uploads on this wiki so the files will be somewhat out of date.

The Lyx document that explains it all is found at: uploads:/noweb/noweb-lyx.lyx

The older notanglefix is found at: uploads:/noweb/notanglefix

4.  Installation

Ultimately you may want to have noweb-lyx.lyx accessible from your build tree so that you can automatically extract the latest notanglefix-filter and Makefile.inc, but generally you will just need to extract a Makefile.inc and notanglefix-filter and put them in your source tree.

For generating better noweave output you will need to change the Lyx noweb convertor to:

sed '/^ *<</s/_/\\_/g' $$i |
sed 's/{\[}{\[}/\[\[/g;s/{\]}{\]}/\]\]/g' |
noweave -delay -index - |
sed 's/@<\\textcompwordmark{}</<\\textcompwordmark{}</g;' |
sed '/[^\\]\\nwbegincode/h;
     /[^\\]\\nwendcode/h;
     /<</{x;/begincode/{x;s/<</<\\textcompwordmark</g;x};x};
     />>/{x;/begincode/{x;s/>>/>\\textcompwordmark>/g;x};x}'
> $$o

The reasoning behind this filter is explained in uploads:/noweb/noweb-lyx.lyx

5.  Usage

If you don't have notanglefix-filter, you can extract it like this:

notangle -Rnotanglefix-filter -filter "
                /bin/sed '/^@nl/d;
                          /@text \\\\end_/d;
                          s/^@text \\\\begin_inset Newline newline/@nl/;
                          s/^@text \\\\backslash/@text \\\\/'
                       " noweb-lyx.lyx

chmod +x notanglefix-filter

6.  Example

Once you have the file ./notanglefix-filter, can invoke like this to generate #line directives in the extracted code; e.g.

 notanglefixlines=1 notangle -f ./notanglefix-filter -Rexample noweb-lyx.lyx

or without the #line directives:

 notangle -f ./notanglefix-filter -Rexample noweb-lyx.lyx

You can also use the older notanglefix to un-mangled extracted source like this:

notangle -Rchunk file.lyx | awk -f notanglefix > chunk

7.  Comments, Bugs

Leave this field for future bugs or comments for your script

A Python clone of noweb is available at https://github.com/JonathanAquino/noweb.py . Since LyX already uses python scripts, I think it may be a good idea checking out this project.

8.  Contributors

• Sam Liddicott

9.  Categories

Category noweb