12 CUSTOMIZATION

The default behavior of FWEB can be changed in a variety of ways.

1. UNIX environment variables (logical variables in VMS) affect path or file names.
2. An initialization file resides in the home directory.
3. 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:

1. Evaluate environment variables. See Environment variables.
2. 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.
3. Process .fweb options beginning with ‘-’ (or ‘+’, for backward compatibility), except for ‘-p’.
4. Read and process command-line options, except for ‘-p’. See Options.
5. Process remaining .fweb options (either file names, or options beginning with ‘&’).
6. Process any ‘-p’ options from .fweb. See -p.
7. Process the style file. See Style.
8. 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.