To provide the credits routines.

§1. Here we compile a routine to print out credits for all the extensions present in the compiled work. This is important because the extensions published at the Inform website are available under a Creative Commons license which requires users to give credit to the authors: Inform ensures that this happens automatically.

Use of authorial modesty (see above) will suppress a credit in the ShowExtensionVersions routine, but the system is set up so that one can only be modest about one's own extensions: this would otherwise violate a CC license of somebody else. General authorial modesty thus suppresses credits for all extensions used which are by the user himself. On the other hand, if an extension contains an authorial modesty disclaimer in its own text, then that must have been the wish of its author, so we can suppress the credit whoever that author was.

In I7FullExtensionVersions all extensions are credited whatever anyone's feelings of modesty.

void RTExtensions::ShowExtensionVersions_routine(void) {
    inter_name *iname = Hierarchy::find(SHOWEXTENSIONVERSIONS_HL);
    packaging_state save = Routines::begin(iname);
    inform_extension *E;
    LOOP_OVER(E, inform_extension) {
        TEMPORARY_TEXT(the_author_name)
        WRITE_TO(the_author_name, "%S", E->as_copy->edition->work->author_name);
        int self_penned = FALSE;
        #ifdef IF_MODULE
        if (PL::Bibliographic::story_author_is(the_author_name)) self_penned = TRUE;
        #endif
        if (((E == NULL) || (E->authorial_modesty == FALSE)) &&  if (1) extension doesn't ask to be modest
            ((general_authorial_modesty == FALSE) ||  and (2) author doesn't ask to be modest, or...
            (self_penned == FALSE))) {  ...didn't write this extension
                TEMPORARY_TEXT(C)
                RTExtensions::credit_ef(C, E, TRUE);  then we award a credit
                Produce::inv_primitive(Emit::tree(), PRINT_BIP);
                Produce::down(Emit::tree());
                    Produce::val_text(Emit::tree(), C);
                Produce::up(Emit::tree());
                DISCARD_TEXT(C)
            }
        DISCARD_TEXT(the_author_name)
    }
    Routines::end(save);
    Hierarchy::make_available(Emit::tree(), iname);

    iname = Hierarchy::find(SHOWFULLEXTENSIONVERSIONS_HL);
    save = Routines::begin(iname);
    LOOP_OVER(E, inform_extension) {
        TEMPORARY_TEXT(C)
        RTExtensions::credit_ef(C, E, TRUE);
        Produce::inv_primitive(Emit::tree(), PRINT_BIP);
        Produce::down(Emit::tree());
            Produce::val_text(Emit::tree(), C);
        Produce::up(Emit::tree());
        DISCARD_TEXT(C)
    }
    Routines::end(save);
    Hierarchy::make_available(Emit::tree(), iname);

    iname = Hierarchy::find(SHOWONEEXTENSION_HL);
    save = Routines::begin(iname);
    inter_symbol *id_s = LocalVariables::add_named_call_as_symbol(I"id");
    LOOP_OVER(E, inform_extension) {
        Produce::inv_primitive(Emit::tree(), IF_BIP);
        Produce::down(Emit::tree());
            Produce::inv_primitive(Emit::tree(), EQ_BIP);
            Produce::down(Emit::tree());
                Produce::val_symbol(Emit::tree(), K_value, id_s);
                Produce::val(Emit::tree(), K_number, LITERAL_IVAL, (inter_ti) (E->allocation_id + 1));
            Produce::up(Emit::tree());
            Produce::code(Emit::tree());
            Produce::down(Emit::tree());
                TEMPORARY_TEXT(C)
                RTExtensions::credit_ef(C, E, FALSE);
                Produce::inv_primitive(Emit::tree(), PRINT_BIP);
                Produce::down(Emit::tree());
                    Produce::val_text(Emit::tree(), C);
                Produce::up(Emit::tree());
                DISCARD_TEXT(C)
            Produce::up(Emit::tree());
        Produce::up(Emit::tree());
    }
    Routines::end(save);
    Hierarchy::make_available(Emit::tree(), iname);
}

§2. The actual credit consists of a single line, with name, version number and author.

void RTExtensions::credit_ef?Usage of RTExtensions::credit_ef:
§1(OUTPUT_STREAM, inform_extension *E, int with_newline) {
    if (E == NULL) internal_error("unfound ef");
    WRITE("%S", E->as_copy->edition->work->raw_title);
    semantic_version_number V = E->as_copy->edition->version;
    if (VersionNumbers::is_null(V) == FALSE) WRITE(" version %v", &V);
    WRITE(" by %S", E->as_copy->edition->work->raw_author_name);
    if (Str::len(E->extra_credit_as_lexed) > 0) WRITE(" (%S)", E->extra_credit_as_lexed);
    if (with_newline) WRITE("\n");
}