The default behavior of FWEB can be changed in a variety of ways.
- UNIX environment variables (logical variables in VMS) affect path or file names.
- An initialization file resides in the home directory.
- A style file resides in the current directory.
The initialization file (usually called .fweb
) is intended to contain
command-line options (one per line) that are to be used in every run.
See Initialization.
The style file (called fweb.sty
by default; see -z) is
intended to provide more local customization, perhaps
differing for each source file and group of source files. The style
file does not contain command-line
options; rather, it contains parameter settings that override
FWEB's defaults. The -p
option (see -p)
may be used to specify a style-file entry in .fweb
(i.e., a
global value for all source files) or on the
command line (i.e., a value used for a single run).
The order of processing is:
- Evaluate environment variables. See Environment variables.
- Read
.fweb
and remember its contents; sort those into three groups: options beginning with-
, beginning with&
, and beginning with a letter (file names) . See Initialization.- Process
.fweb
options beginning with-
(or+
, for backward compatibility), except for-p
.- Read and process command-line options, except for
-p
. See Options.- Process remaining
.fweb
options (either file names, or options beginning with&
).- Process any
-p
options from.fweb
. See -p.- Process the style file. See Style.
- Process any
-p
options from the command line.
Unfortunately, because not all options are processed immediately when
they are read, errors may not show up when one expects. For example,
nothing is actually processed while .fweb
is being read; its
contents are just being stored. It
could therefore happen that a syntax error in entering a -p
option in .fweb
may not be reported until after the style file
has been read, possibly confusing the user as to the source of the
error.