tangle(1)
NAME
tangle - translate WEB to Pascal
SYNOPSIS
tangle [options] webfile[.web] [changefile[.ch]]
DESCRIPTION
This manual page is not meant to be exhaustive. The complete
documentation for this version of TeX can be found in the info file or
manual Web2C: A TeX implementation.
The tangle program converts a Web source document into a Pascal program
that may be compiled in the usual way with the on-line Pascal compiler
(e.g., pc(1)). The output file is packed into lines of 72 characters
or less, with the only concession to readability being the termination
of lines at semicolons when this can be done conveniently.
The Web language allows you to prepare a single document containing all
the information that is needed both to produce a compilable Pascal
program and to produce a well-formatted document describing the program
in as much detail as the writer may desire. The user of Web must be
familiar with both TeX and Pascal. Web also provides a relatively
simple, although adequate, macro facility that permits a Pascal program
to be written in small easily-understood modules.
The command line should have either one or two names on it. The first
is taken as the Web file (and .web is added if there is no extension).
If there is another name, it is a change file (and .ch is added if
there is no extension). The change file overrides parts of the Web
file, as described in the Web system documentation.
The output files are a Pascal file and a string pool file, whose names
are formed by adding .p and .pool respectively to the root of the Web
file name.
OPTIONS
This version of tangle understands the following options. Note that
some of these options may render the output unsuitable for processing
by a Pascal compiler.
--help Print help message and exit.
--length number
Compare only the first number characters of identifiers when
checking for collisions. The default is 32, the original tangle
used 7.
--loose
When checking for collisions between identifiers, honor the
settings of the --lowercase, --mixedcase, --uppercase, and
--underline options. This is the default.
--lowercase
Convert all identifiers to lowercase.
--mixedcase
Retain the case of identifiers. This is the default.
--strict
When checking for collisions between identifiers, strip
underlines and convert all identifiers to uppercase first.
--underline
Retain underlines (also known as underscores) in identifiers.
--uppercase
Convert all identifiers to uppercase. This is the behaviour of
the original tangle.
--version
Print version information and exit.
ENVIRONMENT
The environment variable WEBINPUTS is used to search for the input
files, or the system default if WEBINPUTS is not set. See tex(1) for
the details of the searching.
SEE ALSO
pc(1), pxp(1) (for formatting tangle output when debugging), tex(1).
Donald E. Knuth, The Web System of Structured Documentation.
Donald E. Knuth, Literate Programming, Computer Journal 27, 97-111,
1984.
Wayne Sewell, Weaving a Program, Van Nostrand Reinhold, 1989, ISBN
0-442-31946-0.
Donald E. Knuth, TeX: The Program (Volume B of Computers and
Typesetting), Addison-Wesley, 1986, ISBN 0-201-13437-3.
Donald E. Knuth, Metafont: The Program (Volume D of Computers and
Typesetting), Addison-Wesley, 1986, ISBN 0-201-13438-1.
These last two are by far the largest extant examples of Web programs.
There is an active Internet electronic mail discussion list on the
subject of literate programming; send a subscription request to
litprog-request@shsu.edu to join.
AUTHORS
Web was designed by Donald E. Knuth, based on an earlier system called
DOC (implemented by Ignacio Zabala). The tangle and weave programs are
themselves written in Web. The system was originally ported to Unix at
Stanford by Howard Trickey, and at Cornell by Pavel Curtis.
Free and Open Source Software