man > CTWILL(1)

CTWILL(1)                              General Commands Manual                             CTWILL(1)

NAME
       ctwill, ctwill-refsort, ctwill-twinx - translate CWEB to TeX with mini-indexes

SYNOPSIS
       ctwill [options] webfile[.w] [{changefile[.ch]|-} [outfile[.tex]]]
       ctwill-refsort < indexfile.ref > indexfile.sref
       ctwill-twinx outfile.tex [outfile.tex ...]  > index.tex

DESCRIPTION
       The  ctwill program converts a CWEB source document into a TeX file that may be formatted and
       printed in the usual way.  It takes appropriate care of typographic details like page  layout
       and  the  use  of indentation, italics, boldface, etc., and it supplies extensive cross-index
       information that it gathers automatically.

       CWEB allows you to prepare a single document containing all the information  that  is  needed
       both  to produce a compilable C/C++ program and to produce a well-formatted document describ‐
       ing the program in as much detail as the writer may desire.  The user of CWEB ought to be fa‐
       miliar with TeX as well as C/C++.

USAGE
       The command line should have one, two, or three names on it.  The first is taken as the  CWEB
       input  file  (and  .w is added if there is no extension).  If there is a second name, it is a
       change file (and .ch is added if there is no extension).  The change file overrides parts  of
       the CWEB file, as described in the documentation.  If there is a third name, it overrides the
       default  name  of the output file, which is ordinarily the same as the name of the input file
       (but on the current directory) with the extension .tex.  If you just want to change the  out‐
       put file name, but don’t have a change file to apply, you can use `-' as the second argument.

       ctwill  is  exactly  like cweave except that it produces much better documentation, for which
       you must work much harder.  You should run ctwill twice, once to prime the pump and  once  to
       get decent answers.  Moreover, you must run the output twice through TeX.

       After tex foo you will have output that looks like final pages except that the entries of mi‐
       ni-indexes  won’t  be alphabetized.  The first run produces a weird file called foo.ref.  Say
       ctwill-refsort < foo.ref > foo.sref and then another tex foo will produce  alphabetized  out‐
       put.

       The ctwill-twinx program compiles a master index for a set of related programs that have been
       processed  by ctwill (not by cweave, mind you!).  The individual programs should define their
       names with a line of the form \def\title{NAME}.  For your convenience, ctwill-twinx grabs the
       first “word” in \title and turns it into uppercase form.  You should adapt file  twinx-start‐
       up.tex for the first page of the master index.

       The  mini-indexes list identifiers that are used but not defined on each two-page spread.  At
       the end of each section, ctwill gives TeX a list of identifiers used in that section and  in‐
       formation about where they are defined.

       The  current  meaning of every identifier is initially \uninitialized.  Then ctwill reads the
       .aux file for your job, if any.

       Before reading the .aux file, ctwill actually looks for a file called system.bux, which  will
       be  read if present.  And after foo.aux, a third possibility is foo.bux.  The general conven‐
       tion is to put definitions of system procedures such as printf into system.bux,  and  to  put
       definitions  found  in  specifically foo-ish header files into foo.bux.  Like the .aux files,
       .bux files should contain only @$ specifications.

       The meaning specified by @$...@> generally has four components: an  identifier  (followed  by
       space),  a  program  name  (enclosed  in braces), a section number (followed by space), and a
       TeX part.

       A special proofmode is provided so that you can check ctwill’s conclusions about cross-refer‐
       ences.  Run ctwill with the flag +P, and TeX will  produce  a  specially  formatted  document
       (without mini-indexes) in which you can check that your specifications are correct.

       More details how to use ctwill can be found in the first sections of its source code, respec‐
       tively  the change file cweav-twill.ch applicable to the cweave.w source.  A complete example
       with all bells and whistles is described in Mini-Indexes for Literate Programs, pages 225–245
       of Knuth’s Digital Typography.

DIFFERENCES TO ORIGINAL CTWILL
       The present incarnation of ctwill and its utilities tries hard to be  a  drop-in  replacement
       for the original package.  There are, however, a few differences worth noting:

       • This version is based on the most recent version of CWEB (4.8).

       • In  TeX Live the utility programs are prefixed with ctwill- and the macro files with ct for
         technical reasons.

       • Options --help, --quiet, --verbose, --version, and flags +c, -i, -o, and  +lX  are  new  in
         CWEBbin and TeX Live.

       • Option  +lX is accompanied by example wrapper files for ctwimac.tex and ctproofmac.tex with
         translated captions for German (+ld).

       • Option +lX is also accompanied by an extended pdfctwimac.tex for production of  PDF  output
         with active hyperlinks (+lpdf).

       • ctwill in TeX Live operates silently by default; use the --verbose option to get the origi‐
         nal behavior.

       • File  lookup with the environment variable CWEBINPUTS is extended to permit several, colon-
         separated, paths; see ENVIRONMENT below.

       • If properly configured, the main program ctwill is localized with the “GNU  gettext  utili‐
         ties”.

OPTIONS
       Options  on the command line may be either turned off with `-' (if they are on by default) or
       turned on with `+' (if they are off by default).  In fact, the  options  are  processed  from
       left  to  right,  so a sequence like --verbose -h will only show the banner line (+b) and the
       progress report (+p), but leave out the happy message (-h).

       • +b: print banner line on terminal

       • +h: print success message on completion

       • +p: print progress report messages

       • +q/-q: shortcut for -bhp; also --quiet (default)

       • +v/-v: shortcut for +bhp; also --verbose

       • +c: check temporary output for changes

       • -e: do not enclose C/C++ material in \PB{...}

       • -f: do not force a newline after every C/C++ statement in output

       • -i: suppress indentation of parameter declarations

       • -o: suppress separation of declarations and statements

       • -x: omit indices, section names, table of contents

       • +P: \input ctproofmac.tex instead of ctwimac.tex

       • +lX/-lX: use macros for language X as of X{ctwimac|ctproofmac}.tex

       • +s: print usage statistics

       • +t: treat typename in a template like typedef

       • --help: display help message and exit

       • --version: output version information and exit

ENVIRONMENT
       The environment variable CWEBINPUTS is used to search for the input files, or the system  de‐
       fault  if CWEBINPUTS is not set.  See tex(1) for the details of the searching.  To avoid con‐
       flicts with other programs that also use the CWEBINPUTS environment, you can be more specific
       and use CWEBINPUTS_cweb for special requirements in CWEB.

       If prepared for NLS support, ctwill like ctangle and cweave  uses  the  environment  variable
       TEXMFLOCALEDIR to configure the parent directory where the “GNU gettext utilities” search for
       translation catalogs.

       These variables are preconfigured in TeX Live’s texmf.cnf.

FILES
       The  location  of  the files mentioned below varies from system to system.  Use the kpsewhich
       utility to find their locations.

       • ctwimac.tex: The default TeX macros \input in the first line of the output file.

       • ctproofmac.tex: If ctwill is invoked with the +P option, it will change the first  line  of
         the output file to \input ctproofmac.tex.

       In  both  cases  you  can  request  some  prefix X with the +lX option, e.g., +ld will \input
       dctwimac.tex and +Pld will \input dctproofmac.tex.  A special application is the use  of  op‐
       tion  +lpdf  that  will \input pdfctwimac.tex for production of PDF output with active hyper‐
       links.

       • webfile.bux: Reference definitions to resolve from other modules.

       • system.bux: Reference definitions to resolve from C/C++ standard library header files  like
         <stdio.h>.

       Other  auxiliary files with references are created automatically by ctwill and the actual in‐
       dex files are created by TeX.

       • cwebman.tex: The CWEB user manual, available in PDF from CTAN (https://ctan.org/pkg/cweb).

SEE ALSO
       • The CWEB System of Structured Documentation: by Donald E. Knuth and Silvio  Levy  (hardcopy
         version of cwebman.tex and the source code listings of common.w, ctangle.w, and cweave.w).

       • Digital Typography: by D. E. Knuth.

       • Literate Programming: by D. E. Knuth.

       • Weaving a Program: by Wayne Sewell.

       cweb(1), tex(1), cc(1)

AUTHORS
       Don Knuth wrote ctwill based on cweave by Silvio Levy and Knuth.
       Contemporary development on https://github.com/ascherer/cwebbin.

Web2c 2023                                  June 5, 2022                                   CTWILL(1)