An overview of the index module's role and abilities.

§1. Prerequisites. The index module is a part of the Inform compiler toolset. It is presented as a literate program or "web". Before diving in:

§2. The Index. All users of the Inform GUI app are familiar with the Index: it's a sort of mini-website giving a detailed picture of the content of the story being created. In the current design, there are seven colour-coded "pages", each divided up into two or more parts called "elements".

In fact, this is only one of the possible "index products". It's also possible to generate an EPS (encapsulated PostScript) file of a spatial map, for example.

Until 2021 the Index for a project was generated by the main inform7 compiler, but a radical refactoring then moved the entire index module into inter instead. Index products are now generated from trees of Inter code, not from Inform projects as such:

                      source text
                          | inform7
                      inter tree
                       /     \
               inter  /       \  inter
    (final module)   /         \   (index module)
                    |           |
                   \|/         \|/
           generated code     Index products
                    | inform6 (or similar)
       Executable products

§3. The index module has a very simple API: point it at a tree of Inter code, say what sort of index you want, and go. See Indexing API for the details, though the details are not much more than that.

§4. Localisation. A new and somewhat experimental addition in 2021 is the ability to localise the Index, that is, to produce an Index in a language other than English. This does not of course aim to translate source text: simply to translate subheadings, notes, and other fixed-wording text in the Index.

As a demonstration, try running a project with:

Use French language index.

You should then find that the index has a French-titled Contents section — only a couple of strings have been localised at present, and those not localised revert to English, so the index still looks basically English. This is all really just laying groundwork.

For how to write localisation files, see Localisation (in html), or follow the example of inform/inform7/Internal/Languages/English/Index.txt.