focal (1) cweave.1.gz

NAME

       ctangle, cweave – translate CWEB to TeX

SYNOPSIS

       ctangle [options] webfile[.w] [{changefile[.ch]|-} [outfile[.c]]]
       cweave [options] webfile[.w] [{changefile[.ch]|-} [outfile[.tex]]]

DESCRIPTION

       The  ctangle  program  converts  a  CWEB source document into a C/C++ program that may be compiled in the
       usual way.  The output file includes #line specifications so that debugging can be done in terms  of  the
       CWEB source file.

       The  cweave  program converts the same CWEB file 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.

DIFFERENCES TO ORIGINAL CWEB

       CWEBbin  tries  hard  to  be  a  drop-in  replacement  for  CWEB, so in general you should not notice any
       differences in invoking the programs nor in the resulting output.  There are, however, a few  differences
       worth noting:

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

       • Option +lX is accompanied by several wrapper files for cwebmac.tex with translated captions for  German
         (+ld), French (+lf), and Italian (+li).

       • CWEB  in  TeX Live  operates  silently  by  default  (as  of 2019); 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  programs  ctangle  and cweave are 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).

       The first batch of options are common to both ctangle and cweave:

       • +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

       • +s: print usage statistics

       • --help: display help message and exit

       • --version: output version information and exit

       There are six other options applicable to cweave only:

       • -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

       • +lX/-lX: use macros for language X as of Xcwebmac.tex

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, ctangle and cweave use 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.

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

       • 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).

       • Literate Programming: by D. E. Knuth.

       • Weaving a Program: by Wayne Sewell.

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

AUTHORS

       Don Knuth wrote WEB for TeX and Pascal.
       Silvio  Levy  designed and developed CWEB by adapting the WEB conventions to C and by recoding everything
       in CWEB.  Knuth began using CWEB and made further refinements.  Many other helpers  are  acknowledged  in
       the CWEB manual.
       As  of  2019,  the  CWEB  system  in  TeX Live  is based on the CWEBbin extension that collects ideas and
       improvements from numerous contributors; see the project page (https://github.com/ascherer/cwebbin).