What to do to make use of the words module in a new command-line tool.

§1. Status. The words module provided as one of the "services" suite of modules, which means that it was built with a view to potential incorporation in multiple tools. It can be found, for example, in inform7, inbuild and words-test, among others. words-test may be useful as a minimal example of a tool using words.

By convention, the modules considered as "services" have no dependencies on other modules except for foundation and other "services" modules.

A tool can import words only if it also imports foundation.

§2. Importing the module. We'll use the term "parent" to mean the tool which is importing words, that is, which will include its code and be able to use it. As with any imported module,

Import: somepath/words

§3. Using callbacks. Shared modules like this one are tweaked in behaviour by defining "callback functions". This means that the parent might provide a function of its own which would answer a question put to it by the module, or take some action on behalf of the module: it's a callback in the sense that the parent is normally calling the module, but then the module calls the parent back to ask for data or action.

The parent must indicate which function to use by defining a constant with a specific name as being equal to that function's name. A fictional example would be


    void Emotions::wow(text_stream *OUT) {
        WRITE("My word!\n");

The words module has only a few callbacks, and they are all optional. The following alphabetical list has references to fuller explanations:

§4. If the selection of a natural language is a meaningful thing to the parent, it can define NATURAL_LANGUAGE_WORDS_TYPE to tell the Preform parser how to refer to these. For example, the supervisor module has:

    @d NATURAL_LANGUAGE_WORDS_TYPE struct inform_language