<<notangle.1>>=
.TH NOWEB 1 "local <<noweb documentation date>>"
.SH NAME
notangle, noweave, nountangle \- noweb, a literate-programming tool
.SH SYNOPSIS
.B notangle
[\fB\-R\fProotname ...] [\fB\-filter\fP command]
[\fB\-L\fP[format]] [file] ...
.br
\fBnountangle\fP 
[\fB\-ml\fP|\fB\-m3\fP|\fB\-c\fP|\fB\-c++\fP|\fB\-awk\fP|\fB\-tex\fP|\fB\-f77\fP|\fB\-f90\fP|\fB\-lisp\fP|\fB\-matlab\fP]
[\fB\-R\fProotname ...] [\fB\-filter\fP command] [\fB\-w\fPwidth] [file] ...
.br
\fBnoweave\fP [options] [file] ...
.SH DESCRIPTION
.I Noweb
is a literate-programming tool like Knuth's
.I WEB,
only simpler.
A 
.I noweb
file contains program source code interleaved with documentation.
When 
.I notangle
is given a 
.I noweb
file, it writes the program on standard output.
When 
.I noweave
is given a 
.I noweb
file, it reads the 
.I noweb
source and produces, on standard output, \fILaTeX\fP, \fITeX\fP, \fItroff\fP,
or \fIHTML\fP
source for typeset documentation.
.I nountangle
converts a literate program into an ordinary program by
turning interleaved documentation into comments.
The file name `\-' refers to standard input.
.SH FORMAT OF NOWEB FILES
<<paragraph describing markup of chunks>>
<<paragraph describing markup of chunks>>=
A 
.I noweb 
file is a sequence of
.IR chunks ,
which may appear in any order.
A chunk may contain code or documentation.
Documentation chunks begin with a line that starts with an at sign (@) 
followed by a space or newline.
They have no names.
Code chunks begin with
.br
@<<\fIchunk name\fP@>>=
.br
on a line by itself.
The double left angle bracket (@<<) must be in the first column.
Chunks are terminated by the beginning of another chunk, or by end of file.
If the first line in the file does not mark the beginning of a
chunk, it is assumed to be the first line of a documentation chunk.
@
<<notangle.1>>=
.PP
Documentation chunks contain text that is ignored by
.I notangle
and copied verbatim to 
standard output
by
.I noweave
(except for quoted code).
.I noweave
can work with \fILaTeX\fP, plain \fITeX\fP, \fItroff\fP or \fIHTML\fP.
With plain \fITeX\fP, it inserts a reference to a 
.I TeX
macro package, \fInwmac\fP, which defines commands like
.B \echapter
and
.B \esection.
.PP
Code chunks contain program source code and references to other code
chunks.
Several code chunks may have the same name;
.I notangle
concatenates their definitions to produce a single chunk, just as does
.IR tangle (1).
Code chunk definitions are like macro definitions;
.I notangle
extracts a program by expanding one chunk (by default, the chunk named
\fB@<<\fP*\fB@>>\fP).
The definition of that chunk contains references to other chunks, which are 
themselves expanded, and so on.
\fInotangle\fP's output is readable; it preserves the indentation of expanded
chunks with respect to the chunks in which they appear.
.PP
Code may be quoted within documentation
chunks by placing double square brackets
(\fB[[\fI...\fB]]\fR) around it.
These double square brackets are ignored by
.I notangle,
but they may be used by 
.I noweave
to give the code special typographic treatment, e.g., hypertext links.
If quoted code ends with three or more square brackets,
.I noweave
chooses the rightmost pair, so that, for example, \fB[[a[i]]]\fR is
parsed correctly.
The names of
code chunks may appear within quoted code unless that quoted code is itself
part of the name of a code chunk.
.PP
<<paragraph on escaping angle brackets>>
<<paragraph on escaping angle brackets>>=
In code, noweb treats unpaired
double left or right angle brackets as literal \fB@<<\fP and \fB@>>\fP.  
To force any
such brackets, even paired brackets or brackets in documentation, 
to be treated as literal, use a preceding at sign (e.g. \fB@@<<\fP).
<<old paragraph on escaping angle brackets>>=
If the double left or right angle bracket is to be used 
in code or documentation,
not as part of a chunk name, it should be preceded by an at sign
(e.g. \fB@@<<\fP), although the at sign is not required in code if there is no 
matching double bracket.
<<notangle.1>>=
.PP
<<paragraph on escaping initial at sign>>
<<paragraph on escaping initial at sign>>=
Some programming or formatting languages may require a single \fB@\fP sign in 
the first column. 
Noweb users may achieve this effect by putting a doubled \fB@@\fP in the first column;
in this position only, it stands for a single \fB@\fP sign.
<<paragraph on marking identifier definitions (no longer used)>>=
Any line beginning with `\fB@ \fP' terminates a code chunk,
but if the line has the form
.br
\fB@ %def \fP\fIidentifiers\fP
.br
it is taken to mean that the preceding chunk defines the identifiers listed 
in 
.IR identifiers .
This list contains identifiers separated by whitespace; 
any sequence of nonwhite characters may be an identifier.
.I noweb
uses a simple heuristic to avoid recognizing identifiers 
that are substrings of other identifiers.
.I "This feature is deprecated."
.I "Instead, I recommend that you use the"
.B btdefn
.I "filter described on the nowebfilters(7) man page."
<<notangle.1>>=
.SH TANGLING
.I notangle
and
.I nountangle
accept the same set of options, although some options have effects only on one 
or the other.
The options are:
.TP
.B \-R\fIname\fR
Expand the \fB@<<\fIname\fB@>>\fR code chunk.
The 
.B \-R
option can be repeated, 
in which case each chunk is written to the output.
If no
.B \-R
option is given, expand the chunk named  \fB@<<\fP*\fB@>>\fP.
.TP
.B \-L\fIformat\fR
Emit line number indications at chunk boundaries.
A line number indication identifies the source of the line that follows it.
In
.IR format ,
.B "%F"
indicates the name of the source file,
.B "%L"
indicates the line number of the source file,
.B "%N"
indicates a newline,
and 
.B "%%"
indicates a percent sign.
A sign and digit may be inserted between the percent sign and the `\fBL\fP',
in which case the line number will be adjusted by that amount.
If 
.I format
is omitted, the default format is that accepted by the C preprocessor:
`\fB#line %L "%F"%N\fR'.
When using the \fB\-L\fIformat\fR option, 
.I notangle
ensures that all text appears in the same column in input and output.
.I nountangle
ignores this option.
.IP " "
Common format strings include:
.ta \w'zzzSunyFORTRANxxxx'u
.nf
   C	\fB\-L'#line %L "%F"%N'\fP
   Sun FORTRAN	\fB\-L'\\# %L "%F"%N'\fP
   Icon	\fB\-L'#line %\-1L "%F"%N'\fP
   Modula-3	\fB\-L'<*LINE %L "%F" *>%N'\fP
   SML/NJ	\fB\-L'(*#line %L "%F"*)'\fP
.fi
.IP " "
To solve the converse problem, that is, to get noweb to do something sensible 
with \fB#line\fP in its input, see the \fBsharpline\fP filter in the examples
directory.
.TP
.B \-t\fIk\fP
Copy tabs untouched from input to output, and use tabs for indentation, 
assuming stops every \fIk\fP columns.
By default, tabs are expanded to spaces with stops every 8 columns.
.TP
.B \-filter \fIcmd\fP
Filter the 
.I noweb
source through 
.I cmd
after converting it to tool form and before tangling.
.I notangle
looks for 
.I cmd
first on the user's
.BR PATH ,
then in
.BR |LIBDIR| .
Such filters
can be used to add features to
.IR notangle ;
for an example see
.BR |LIBDIR|/emptydefn .
For experts only.
<<description of -markup option>>
.TP
.B "\-awk | \-c | \-icn | \-icon | \-ml | \-m3 | \-pascal | \-f77 | \-f90 | \-tex"
When 
.I nountangle
transforms documentation chunks into comments, use the comment format of the language
named.
.B \-c
is the default.
.I notangle
ignores these options.
.TP
.B \-w\fIn\fP
When 
.I nountangle
transforms documentation chunks into comments, create comments on lines of width \fIn\fP.
.I notangle
ignores this option.
.SH WEAVING
<<man page: WEAVING section>>
.SH INDEXING AND CROSS-REFERENCE
<<man page: INDEXING AND CROSS-REFERENCE section>>
When used with 
.IR LaTeX ,
.IR troff ,
or
.I HTML,
.I noweave
can provide indexing and cross-reference information for chunks and for 
programming-language identifiers.
Identifier definitions may be marked by hand using backticks (`); the 
\fB-filter btdefn\fP option recognizes these markings.
For some languages, definitions may be found automatically using the 
\fB-autodefs\fP option.
This section describes the indexing and cross-reference options;
it might well be skipped on first reading.
<<noweave man page indexing options>>
.SH ERROR MESSAGES
If
.I notangle
or
.I noweave
encounters a chunk name within documentation, it assumes that this
indicates an error, usually misspelling ``@<<name@>>=''.
Other error messages should be self-explanatory.
.PP
It is incorrect to refer to a chunk that is never
defined, but it is OK for chunks to be defined and not used.
.SH EXAMPLES
If you have trouble digesting this man page, you're not alone.
Here are a few examples to get you started.
I'll assume you have a
.B foo.nw
file with a C program in chunk 
.B @<<foo.c@>>
and a header file in chunk
.BR @<<foo.h@>> ,
and that your documentation is marked up using
.IR latex(1) .
I'll show you how to build things using the most common options.
.PP
To rebuild your C source, try
.RS
.B "notangle \-L \-Rfoo.c foo.nw > foo.c"
.RE
To rebuild your header file, try
.RS
.B "notangle \-Rfoo.h foo.nw | cpif foo.h"
.RE
There are two compromises here.
Omitting \fB\-L\fP keeps \fB#line\fP out of your header file,
and using \fBcpif\fP prevents the command from rewriting 
.B foo.h
unless the contents have changed.  Thus, this is good code to put in a Makefile rule.
.PP
To build a printed document, run
.RS
.B "noweave \-autodefs c \-index foo.nw > foo.tex"
.RE
If you have your own preamble, containing \fB\\documentclass\fP and all, 
you will also need the \fB\-delay\fP option.
.PP
To build a web page, run
.RS
.B "noweave \-filter l2h \-autodefs c \-index \-html foo.nw | htmltoc > foo.html"
.RE
Have fun!
.SH FILES
.PP
.ta \w'|TEXINPUTS|nwkernel.texxxxx'u
.nf
|LIBDIR|/markup	markup preprocessor
|LIBDIR|/unmarkup	inverts markup
|LIBDIR|/nt	notangle proper
|LIBDIR|/finduses	find uses of identifiers for index
|LIBDIR|/noidx	generate index and cross-reference info
|LIBDIR|/toroff	back end to emit \fItroff\fP
|LIBDIR|/totex	back end to emit \fITeX\fP or \fILaTeX\fP
|LIBDIR|/tohtml	back end to emit HTML
|TEXINPUTS|/nwmac.tex	formatting \fITeX\fP macros
|TEXINPUTS|/noweb.sty	use in \fILaTeX\fP documents; see \fInowebstyle(7)\fP
.fi
.SH SEE ALSO
.PP
.IR cpif (1),
.IR nodefs (1),
.IR noroots (1),
.IR noweb (1),
.IR noindex (1),
.IR noroff (1),
.IR nowebstyle (7),
.IR nowebfilters (7)
.SH BUGS
.I notangle 
and
.I nountangle
fail if names used on the command line contain single quotes.
.PP
Ignoring unused chunks can cause problems;
if a chunk has
multiple definitions and one is misspelled,
the misspelled definition is silently ignored.
.IR noroots (1)
can be used to catch this mistake.
\".PP
\".I noweb
\"requires the new version of
\".IR awk ,
\"assumed to be called
\".IR nawk .
\"DEC
\".I nawk
\"has a bug in that that causes 
\".B noweave
\"to fail to translate braces correctly.
\"GNU 
\".I gawk
\"is reported to work.
\".PP
\"DEC 
\".I sh
\"has a bug that causes the
\".B \-filter
\"option to fail whenever the filter command contains more than one word.
.PP
The 
.I "-L"
option of
.I notangle
puts an implicit initial newline in the format string.
.PP
<<paragraph about bogus latex pagestyles>>
.PP
.IR latex2html (1)
mangles some source files.
.PP
.I noweave
has too many options, and this man page is too long.
<<AUTHOR section>>
<<description of -markup option>>=
.TP
.B "\-markup \fIparser\fP"
Use 
.I parser
to parse the input file.
Enables use of noweb tools on files in other formats;
for example, the 
.B numarkup
parser understands
.IR nuweb (1)
format.
See 
.IR nowebfilters (7)
for more information.
For experts only.
<<paragraph about bogus latex pagestyles>>=
The default
.I LaTeX
pagestyles don't set the width of the boxes containing headers and footers.
Since 
.I noweb
code paragraphs are extra wide, this 
.I LaTeX
bug sometimes results in extra-wide headers and footers.
The remedy is to redefine the relevant 
.B ps@*
commands;
.B ps@noweb
in 
.B noweb.sty
can be used as an example.
@
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
<<noweb.1>>=
.TH NOWEB 1 "local <<noweb documentation date>>"
.SH NAME
noweb \- a simple literate-programming tool
.SH SYNOPSIS
.B noweb
[\fB-t\fP] 
[\fB-o\fP] 
[\fB-L\fP\fIformat\fP] 
[\fB-markup\fP \fIparser\fP]
[file] ...
.SH DESCRIPTION
.I Noweb
is a literate-programming tool like
.I FunnelWEB
or 
.IR nuweb ,
only simpler.
A 
.I noweb
file contains program source code interleaved with documentation.
When 
.I noweb
is invoked, it writes the program source code 
to the output files mentioned in the noweb file, and it writes a 
.I TeX
file for typeset documentation.
.PP
The 
.IR noweb (1)
command is for people who don't like reading man pages or who are switching from 
.IR nuweb .
To get the most out of
.IR noweb ,
use
.IR notangle (1)
and 
.IR noweave (1)
instead.
.SH FORMAT OF NOWEB FILES
<<paragraph describing markup of chunks>>
.PP
Documentation chunks contain text that is copied verbatim to the
.I TeX
file (except for quoted code).
.I noweb
works with \fILaTeX\fP; the first documentation chunk must contain
a 
.I LaTeX
.B "\\\\documentclass"
command, it must contain
.B "\\\\usepackage{noweb}"
in the preamble, and finally
it must also contain a 
.I LaTeX
.B "\\\\begin{document}"
command.
.PP
Code chunks contain program source code and references to other code
chunks.
Several code chunks may have the same name;
.I noweb
concatenates their definitions to produce a single chunk, just as
other literate-programming tools do.
.I noweb
looks for chunks that are defined but not used in the source file.
If the name of such a chunk contains no spaces, the chunk is
an ``output file;''
.I noweb
expands it and writes the result onto the file of the same name.
A code-chunk definition is like a macro definition;
it contains references to other chunks, which are 
themselves expanded, and so on.
\fInoweb\fP's output is readable; it preserves the indentation of expanded
chunks with respect to the chunks in which they appear.
.PP
If a star (\fB*\fP) is appended to the name of an output file,
.I noweb
includes line-number information as specified by the \fB\-L\fP\fIformat\fP
option (or for C if no \fB\-L\fP\fIformat\fP option is given).
The name itself may not contain shell metacharacters.
.PP
Code may be quoted within documentation
chunks by placing double square brackets
(\fB[[\fI...\fB]]\fR) around it.
These double square brackets are used to
give the code special typographic treatment in the
.I TeX
file.
If quoted code ends with three or more square brackets,
.I noweb
chooses the rightmost pair, so that, for example, \fB[[a[i]]]\fR is
parsed correctly.
.PP
<<paragraph on escaping angle brackets>>
.SH OPTIONS
.TP
.B \-t
Suppress generation of a 
.I TeX
file.
.TP
.B \-o
Suppress generation of output files.
.TP
.B \-L\fIformat\fR
Use 
.I format
to format line-number information for starred output files.
(If the option is omitted, a format suitable for C is used.)
.I format
is as defined by 
.IR notangle (1);
<<description of -markup option>>
.SH BUGS
.PP
Ignoring unused chunks whose names contain spaces
sometimes causes problems, especially in the case when a chunk has
multiple definitions and one is misspelled;
the misspelled definition will be silently ignored.
.IR noroots (1)
can be used as a sanity checker to catch this sort of mistake.
.PP
.I noweb
is intended for users who don't want the power or the complexity of 
command-line options.
More sophisticated users should avoid
.I noweb
and use 
.I noweave 
and 
.I notangle
instead.
If the design were better, we could all use the same commands.
.PP
.I noweb
requires the new version of
.IR awk ,
assumed to be called
.IR nawk .
DEC
.I nawk
has a bug in that that causes problems with braces in
.I TeX
output.
GNU 
.I gawk
is reported to work.
.PP
<<paragraph about bogus latex pagestyles>>
.SH SEE ALSO
.PP
.IR notangle (1),
.IR noweave (1),
.IR noroots (1),
.IR nountangle (1),
.IR nowebstyle (7),
.IR nowebfilters (7),
.IR nuweb2noweb (1)
.br
Norman Ramsey,
.I "Literate programming simplified, IEEE Software"
11(5):97-105, September 1994.
<<AUTHOR section>>
<<nowebstyle.7>>=
.TH NOWEB 7 "local <<noweb documentation date>>"
.SH NAME
nowebstyle \- \fILaTeX\fP package for \fInoweb\fP
.SH SYNOPSIS
.B "\\\\usepackage{noweb}"
.SH DESCRIPTION
When 
.I noweave
generates code for 
.IR LaTeX ,
the
.B noweb
package is required.
In addition to the necessary arcana, it
defines a 
.B webcode
environment in which you can place fragments of 
code, and in which
only backslash and curly braces have their special meanings;
all other characters are taken literally.
It also defines a
.B noweb
pagestyle.
Finally, it defines a
.B "\\\\noweboptions{...}"
command that can be used to tinker with the appearance of the output.
Options are separated by commas and include:
<<man page: [[\noweboptions]]>>
.SH CONTROL SEQUENCES
The noweb package describes a gazillion special control sequences.
Only a few are listed here.
<<man page: noweb style control sequences>>
.SH SEE ALSO
.IR noweave (1),
.IR noweb (1)
<<AUTHOR section>>
@ 
<<cpif.1>>=
.TH CPIF 1 "local <<noweb documentation date>>"
.SH NAME
cpif \- selectively update files
.SH SYNOPSIS
.B cpif
[\fB\-eq\fP|\fB\-ne\fP] file ...
.SH DESCRIPTION
.I cpif
is an auxiliary tool for use with 
.IR notangle (1)
and
.IR make (1).
.I cpif
compares its standard input to each of the named files,
overwriting the file if the comparison succeeds or if
the named file does not exist.
If neither
.B \-eq
or 
.B \-ne
is specified, the default is
.BR \-ne .
Typical usage is in the following default rule, suitable for use in a Makefile.
.br
 .nw.h: ; notangle \-Rheader $*.nw | cpif $*.h
.br
.SH SEE ALSO
.IR notangle (1)
<<AUTHOR section>>
@ 
<<nuweb2noweb.1>>=
.TH NOWEB 1 "<<noweb documentation date>>"
.SH NAME
nuweb2noweb \- convert nuweb files to noweb form
.SH SYNOPSIS
.B nuweb2noweb
file ...
.SH DESCRIPTION
.I Nuweb2noweb
converts a file or files in 
.I nuweb
format to
.I noweb
format, writing the results on standard output.
Input is from the file(s) named on the command line.
.SH SEE ALSO
.PP
.IR noweb (1),
.IR nuweb (1)
<<AUTHOR section>>
@ 

