Noweb

noweb is a free literate programming tool,created in 1989-1999 by Norman Ramsey [http://www.eecs.harvard.edu/~nr/index.html] ,and designed to be simple, easily extensible and language independent.

Like in WEB and CWEBmain components of noweb are two programs:"notangle", which extracts 'machine' source code from the source texts,and "noweave", which produces nicely-formatted printable documentation.

noweb 'out of the box' supports TeX, LaTeX, HTML, and troff back ends and works with any programming language.Besides simplicity this is the main advantage over WEB, whichneeds different versions to support programming languagesother than Pascal.(Thus the necessity of CWEB, which supports C andsimilar languages.)

Noweb's input

A noweb input text contains program source code interleaved with documentation.It consists of so-called "chunks" that areeither "code-chunks" or "documentation-chunks".

It uses LaTeX code for "documentation chunks", but you mayeasily use any form you like.

"Code chunks" aren't treated speciallyby noweb's tools - they may be placed in any orderand when needed, they are just concatenated,chunk-references in code are dereferenced andthe whole requested source code is extracted.

Example of a simple noweb program

This is an example of a hello-world program(s) with documentation:

@ section{Hello world} Today I awakened and decided to write some code, so I started to write a Hello World in extsf C. <>= /* <> */ #include int main(int argc, char *argv [] ) { printf("Hello World! "); return 0; } @ oindent ldots then I did the same in PHP. <>= > */ echo "Hello world! "; ?> @ section{License} Later, same day some lawyer reminded me about licenses. So, here it is: <>= This work is placed in the public domain. @

Assuming that the above code is placed in a file named 'hello.noweb',the command to extract the human-readable document in HTML format is:

noweave -filter l2h -index -html hello.noweb | htmltoc > hello.html

... and in LaTeX format:

noweave -index -latex hello.noweb > hello.tex

To extract machine source code:

notangle -Rhello.c hello.noweb > hello.c

notangle -Rhello.php hello.noweb > hello.php

See also

*WEB
*CWEB

External links

* [http://www.eecs.harvard.edu/~nr/noweb/ Noweb home page]
* [http://www.eecs.harvard.edu/~nr/index.html Norman Ramsey's home page]
* [http://www.cs.virginia.edu/cgi-bin/manpage?section=1&topic=notangle notangle online man page]