Unix Programming - make: Automating Your Recipes

The Art of Unix Programming
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Unix Programming - make: Automating Your Recipes - make in Non-C/C++ Development

make in Non-C/C++ Development

Suppose, for example, that you actually generate part of your code from a specification file, using one of the techniques from Chapter9. You can use make to tie the spec file and the generated source together. This will ensure that whenever you change the spec and remake, the generated code will automatically be rebuilt.

It's quite common to use makefile productions to express recipes for making documentation as well as code. You'll often see this approach used to automatically generate PostScript or other derived documentation from masters written in some markup language (like HTML or one of the Unix document-macro languages we'll survey in Chapter18). In fact, this sort of use is so common that it's worth illustrating with a case study.

Case Study: make for Document-File Translation

In the fetchmail makefile, for example, you'll see three productions that relate files named FAQ, FEATURES, and NOTES to HTML sources fetchmail-FAQ.html, fetchmail-features.html, and design-notes.html.

The HTML files are meant to be accessible on the fetchmail Web page, but all the HTML markup makes them uncomfortable to look at unless you're using a browser. So the FAQ, FEATURES, and NOTES are flat-text files meant to be flipped through quickly with an editor or pager program by someone reading the fetchmail sources themselves (or, perhaps, distributed to FTP sites that don't support Web access).

The flat-text forms can be made from their HTML masters by using the common open-source program lynx(1). lynx is a Web browser for text-only displays; but when invoked with the -dump option it functions reasonably well as an HTML-to-ASCII formatter.

With the productions in place, the developer can edit the HTML masters without having to remember to manually rebuild the flat-text forms afterwards, secure in the knowledge that FAQ, FEATURES, and NOTES will be properly rebuilt whenever they are needed.