Section 5.3.5.3.1.4. The ancillary format file

Because a printed paper may be more verbose than its parent CIF data file, it is necessary to add text to the output from ciftex to represent section headings, line spaces or other formatting instructions. The program reads an ancillary file, known as the format file, for such additional text.

Each line in the format file begins with a hash mark #, a single ASCII character and a colon. The second character is chosen to match the corresponding locator character associated with data names in the map file. The rest of the line is text to be output. When the locator character associated with the data name currently being processed differs from the previous one, the output text from all lines in the format file with the new locator character are output.

The special strings #[: and #]: indicate text to be emitted at the beginning and end of the output stream, respectively.

Fig. 5.3.5.8 is an example of a simplified format file. The first line is printed at the start of the output file; the second line at the end. The next line will be printed on the first occurrence of a data name flagged with the locator code a in the map file. In this example, that will be the name or address of an author of the paper; some typographic directives are emitted immediately before the authors' names and addresses, including the introduction of a blank line (`vertical skip', or `vskip') of height 10 typographic points.

Figure 5.3.5.8 | top | pdf | Example format file for ciftex.

The lines beginning #g: are emitted immediately before the first data name in the group that is associated with locator code g. In this example, the effect is to output a heading and subheading before printing the cell-length parameters and to switch to double-column format. The line containing only the characters #g: provides for the introduction of a blank line into the file, with the sole purpose of making the file more readable by human editors.

The lines beginning #U: are emitted at the beginning of the table of anisotropic U values.

The mechanism looks complicated at first sight, but addresses the need to generate headings at standard locations in a printed paper when the exact content of the paper is not known in advance.

The different format for directives in the map and format files means that the same file can be used for both purposes, if required. In practice it is often easier to maintain different files: the same mapping between CIF data names and macros might be common to different journals, while each journal uses its own format file.