Customizing GED2HTML Output under Unix

The output produced by GED2HTML is extensively customizable to suit the tastes of individual users. There are two main ways to customize the output: (1) by selecting various options settings on the GED2HTML command line; (2) by modifying or rewriting the output program that controls the generation of the HTML output. Most people will probably find the amount of customization that can be performed via the command line options to be adequate for their needs. We discuss the mechanics of making these customizations below. Modifying the output programs is more involved, and is discussed here.

GED2HTML understands command-line arguments according to the following "Unix man page style" synopsis:

ged2html [-HvDft] [[--] <gedcom-file> ...] The various arguments have the following meanings:

The -H argument causes GED2HTML to print a brief message listing the available arguments.
The -v option causes GED2HTML to print out its version number and copyright information.
The -D option takes a single argument, which has the form "VARIABLE=VALUE", where VARIABLE is the name of an output interpreter variable to be initialized, and VALUE is an integer or string value to which it is to be initialized. If the VALUE starts with a digit, then it is regarded as an integer, otherwise it is regarded as a string. If the VALUE starts with a double quote ("), then it is interpreted as a string. In this case, the value must also end with a double quote, and the intervening characters are the characters in the string.
The -f option takes a single argument, which is interpreted as the name of an options file. The options template file must be in the format of an GED2HTML output program (see here for more details) containing the definition of a single procedure, "set_options", whose purpose is to assign initial values to variables of the output interpreter that control GED2HTML processing. Any settings in the options file override defaults, but can themselves be overridden by initializations specified on the command line using the "-D" option, or by statements in the procedure "do_initialize" in the output program.
The following is a simple example of an options file.
define set_options { set LANGUAGE to "French" set INDIVIDUALS_PER_FILE to 20 }
The -t option takes a single argument. If the argument is '-', then GED2HTML dumps the source code for its built-in output program to the standard output. Otherwise, the argument is interpreted as a file name and the output program is dumped to that file. This option is used for obtaining the exact source code to the built-in output program, so that it can be used as a starting point for customizations. See here for information on output programs.

Nearly all the processing options that can be selected in a GED2HTML run are accessed by initializing certain variables of the output interpreter to have certain values. Initialization of output interpreter variables can be accomplished in three different ways:

By using the -D command line option to initialize the variables.
By using the -f command line option to select an options file. The "set_options" procedure in the options file is executed before any other processing occurs, for the purpose of initializing output interpreter variables.
By adding code to the procedure "do_initialize" in the output program, to perform the desired initializations.

For a list of all the output interpreter variables that can be initialized to select processing options, see here.

Order of Options Processing

As indicated above, GED2HTML has several different mechanisms for selecting options that modify its behavior. A summary of these mechanisms, in the order in which they occur when GED2HTML is run is the following:

When GED2HTML starts, predefined default values are set for all the options.
If an options file has been specified using the "-f" command line flag, then this file is read and compiled by the GED2HTML output language compiler. Then, the procedure "set_options" in this file is executed by the GED2HTML output language interpreter.
GED2HTML processes any additional options the user might have specified using the "-D" command line flag. Any such additional options settings override those from steps (1) and (2).
If an assignment has been made to the OUTPUT_PROGRAM option variable in step (2) or (3), then the specified output program is located and compiled. Otherwise, the built-in standard output program is used.
GED2HTML executes the procedure do_initialize in the output program. Any options settings made in this procedure will override those made in previous steps.
GED2HTML reads the GEDCOM file and produces output.

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