NAME

       ctwill, ctwill-refsort, ctwill-twinx – translate CWEB to TeX
       with mini-indexes per spread or per section

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
       describing the program in as much detail as the writer may desire.  The user of CWEB ought
       to be familiar 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 output 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 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
       mini-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
       output.

       The  ctwill-twinx  program compiles a master index for a set of related programs that have
       been processed by ctwill.  The individual programs should define their names with  a  line
       of the form \def\title{NAME}.

       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 information 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
       convention 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-
       references.   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,
       respectively 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 (3.64c).

       • 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 -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).

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

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

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

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

       • -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

       • --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
       default if CWEBINPUTS is not set.  See tex(1) for the details of the searching.

       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.

       • 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
       index 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.
       As  of  2019,  ctwill  and  its  utilities ctwill-refsort and ctwill-twinx have been fully
       integrated with the extended CWEBbin system that serves as the basis for CWEB in TeX Live;
       see the project page (https://github.com/ascherer/cwebbin).