tangle - translate WEB to Pascal
tangle [
options]
webfile[
.web] [ {
changefile[
.ch] |-} [
outfile[
.p] ]
]
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 one, two or three names on it. The first is taken
as the Web file (and
.web is added if there is no extension). If there
is second 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.
If there is a third name, it is the Pascal output file (and
.p is added
if there is no extension). In this case you can specify an empty change file
with '-' as the second argument. Otherwise the name of the Pascal file is
formed by adding
.p to the root of the Web file name.
An optional second output file is a string pool file, whose name is formed by
adding
.pool to the root of the Pascal file name.
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.
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.
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
[email protected] to join.
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.