To manage the special variables providing bibliographic data on the work of IF being generated (title, author's name and so forth), and to write the Library Card in the index.
§2. Much of this section is best understood by reference to the Treaty of Babel, a cross-IF-system standard for bibliographic data and packaging agreed between the major IF design systems in 2006. Inform aims to comply fully with the Treaty and the code below should be maintained as such.
The bibliographic data for the story is kept in the following variables, which are used to build the iFiction record and the releasing blurb at the end of a successful compilation.
nonlocal_variable *story_title_VAR = NULL;
nonlocal_variable *story_author_VAR = NULL;
nonlocal_variable *story_headline_VAR = NULL;
nonlocal_variable *story_genre_VAR = NULL;
nonlocal_variable *story_description_VAR = NULL;
nonlocal_variable *story_release_number_VAR = NULL;
nonlocal_variable *story_creation_year_VAR = NULL;
int episode_number = -1; for a work which is part of a numbered series
wchar_t *series_name = NULL;
§3. This is organised as a plugin since it's all broadly IF-based, and not something you'd expect in a general programming language. But the main effect is only to make a small number of variables special.
void PL::Bibliographic::start(void) {
PLUGIN_REGISTER(PLUGIN_NEW_VARIABLE_NOTIFY, PL::Bibliographic::bibliographic_new_variable_notify);
}
The function PL::Bibliographic::start appears nowhere else.
§4. The following grammar contains the names of all of the bibliographic variables — those used to set entries on the Library Card about a project. As usual, Inform uses these English wordings to detect the creation of the variables in the Standard Rules, which are in English: so there's no point in translating this nonterminal to other languages.
<notable-bibliographic-variables> ::=
story title |
story author |
story headline |
story genre |
story description |
story creation year |
release number
define STORY_TITLE_BIBV 0
define STORY_AUTHOR_BIBV 1
define STORY_HEADLINE_BIBV 2
define STORY_GENRE_BIBV 3
define STORY_DESCRIPTION_BIBV 4
define STORY_CREATION_YEAR_BIBV 5
define RELEASE_NUMBER_BIBV 6
int PL::Bibliographic::bibliographic_new_variable_notify(nonlocal_variable *q) {
if (<notable-bibliographic-variables>(q->name)) {
switch (<<r>>) {
case STORY_TITLE_BIBV: story_title_VAR = q; break;
case STORY_AUTHOR_BIBV: story_author_VAR = q; break;
case STORY_HEADLINE_BIBV: story_headline_VAR = q; break;
case STORY_GENRE_BIBV: story_genre_VAR = q; break;
case STORY_DESCRIPTION_BIBV: story_description_VAR = q; break;
case STORY_CREATION_YEAR_BIBV: story_creation_year_VAR = q; break;
case RELEASE_NUMBER_BIBV: story_release_number_VAR = q; break;
}
NonlocalVariables::make_constant(q, TRUE);
}
return FALSE;
}
The function PL::Bibliographic::bibliographic_new_variable_notify is used in §3.
§6. This is what the top line of the main source text should look like, if it's to declare the title and author.
<titling-line> ::=
<plain-titling-line> ( in <natural-language> ) | ==> R[1]; *XP = RP[2];
<plain-titling-line> ==> R[1]; *XP = NULL;
<plain-titling-line> ::=
{<quoted-text-without-subs>} by ... | ==> TRUE
{<quoted-text-without-subs>} ==> FALSE
§7. That grammar is used at two points: first, to spot the natural language being used in the source text, something we have to look ahead to since it affects the grammar needed to understand the rest of the file —
natural_language *PL::Bibliographic::scan_language(parse_node *PN) {
if (<titling-line>(ParseTree::get_text(PN))) return <<rp>>;
return NULL;
}
The function PL::Bibliographic::scan_language appears nowhere else.
§8. — and secondly, to parse the titling-line sentence in the regular way, setting bibliographic variables as needed. The following is called on the first sentence in the source text if and only if it begins with text in double quotes:
void PL::Bibliographic::bibliographic_data(parse_node *PN) {
if (<titling-line>(ParseTree::get_text(PN))) {
wording TW = GET_RW(<plain-titling-line>, 1);
wording AW = EMPTY_WORDING;
if (<<r>>) AW = GET_RW(<plain-titling-line>, 2);
if ((story_title_VAR) && (story_author_VAR)) {
<Set the story title from the titling line 8.1>;
if (Wordings::nonempty(AW)) <Set the author from the titling line 8.2>;
}
} else {
Problems::Issue::sentence_problem(_p_(PM_BadTitleSentence),
"the initial bibliographic sentence can only be a title in double-quotes",
"possibly followed with 'by' and the name of the author.");
}
}
The function PL::Bibliographic::bibliographic_data appears nowhere else.
§8.1. We must not of course simply write to the variables; we call the assertion machinery to generate an inference about their values, because that ensures that contradictions, and so forth, are properly complained about.
<Set the story title from the titling line 8.1> =
parse_node *the_title;
if (<s-value>(TW)) the_title = <<rp>>;
else the_title = Specifications::new_UNKNOWN(TW);
Assertions::PropertyKnowledge::initialise_global_variable(story_title_VAR, the_title);
Strings::TextLiterals::suppress_quote_expansion(ParseTree::get_text(the_title));
This code is used in §8.
§8.2. The author is often given outside of quotation marks:
"The Large Scale Structure of Space-Time" by Lindsay Lohan
and in such cases we transcribe the name-words into quotes so that we can treat them as a text literal ("Lindsay Lohan").
<Set the author from the titling line 8.2> =
TEMPORARY_TEXT(author_buffer);
if (<quoted-text>(AW) == FALSE) {
WRITE_TO(author_buffer, "\"%+W", AW);
for (int i=1, L=Str::len(author_buffer); i<L; i++)
if (Str::get_at(author_buffer, i) == '\"')
Str::put_at(author_buffer, i, '\'');
WRITE_TO(author_buffer, "\" ");
AW = Feeds::feed_stream(author_buffer);
}
DISCARD_TEXT(author_buffer);
parse_node *the_author;
if (<s-value>(AW)) the_author = <<rp>>;
else the_author = Specifications::new_UNKNOWN(AW);
Assertions::PropertyKnowledge::initialise_global_variable(story_author_VAR, the_author);
This code is used in §8.
§9. This unattractive routine performs a string comparison of the author's name against one that's supplied, case sensitively, and is used when deciding whether to print credits at run-time for extensions written by the same person as the author of the main work.
int PL::Bibliographic::story_author_is(text_stream *p) {
if ((story_author_VAR) &&
(NonlocalVariables::has_initial_value_set(story_author_VAR))) {
parse_node *spec = NonlocalVariables::get_initial_value(story_author_VAR);
ParseTree::set_kind_of_value(spec, K_text);
int result = FALSE;
TEMPORARY_TEXT(TEMP);
wording W = ParseTree::get_text(spec);
int w1 = Wordings::first_wn(W);
HTMLFiles::compile_bibliographic_text(TEMP, Lexer::word_text(w1));
if (Str::eq(TEMP, p)) result = TRUE;
DISCARD_TEXT(TEMP);
return result;
}
return FALSE;
}
The function PL::Bibliographic::story_author_is appears nowhere else.
§10. Inform probably shouldn't support this sentence, which does nothing other than to fill in two pieces of rarely-used bibliographic data (which could just as easily be variables). But two of the larger worked examples we were trying Inform out on, in the early days, belonged to a sequence called "When in Rome". So it didn't seem such an obscure request at the time.
This is episode 2 of "When in Rome".
The subject noun phrase is fixed, so the information is in the object NP, which must match:
<episode-sentence-subject> ::=
<definite-article> story |
this story |
story
<episode-sentence-object> ::=
episode <cardinal-number> of <quoted-text-without-subs> | ==> R[1]; <<series>> = R[2];
episode ... ==> <Issue PM_BadEpisode problem 10.1>;
§10.1.
<Issue PM_BadEpisode problem 10.1> =
*X = -1;
Problems::Issue::sentence_problem(_p_(PM_BadEpisode),
"this is not the right way to specify how the story "
"fits into a larger narrative",
"and should take the form 'The story is episode 2 of "
"\"Belt of Orion\", where the episode number has to be a "
"whole number 0, 1, 2, ... and the series name has to be "
"plain text without [substitutions].");
This code is used in §10.
§11. This handles the special meaning "The story is episode...".
int PL::Bibliographic::episode_SMF(int task, parse_node *V, wording *NPs) {
wording SW = (NPs)?(NPs[0]):EMPTY_WORDING;
wording OW = (NPs)?(NPs[1]):EMPTY_WORDING;
switch (task) { "The story is episode 2 of ..."
case ACCEPT_SMFT:
if ((<episode-sentence-subject>(SW)) && (<episode-sentence-object>(OW))) {
ParseTree::annotate_int(V, verb_id_ANNOT, SPECIAL_MEANING_VB);
if (<<r>> >= 0) {
episode_number = <<r>>;
Word::dequote(<<series>>);
series_name = Lexer::word_text(<<series>>);
}
return TRUE;
}
break;
}
return FALSE;
}
The function PL::Bibliographic::episode_SMF appears nowhere else.
§12. In the I6 template layer, some of the bibliographic variables are actually compiled to constants, used early on at run-time to print the banner.
void PL::Bibliographic::compile_constants(void) {
encode_constant_text_bibliographically = TRUE;
BEGIN_COMPILATION_MODE;
COMPILATION_MODE_ENTER(COMPILE_TEXT_TO_I6_CMODE);
if (story_title_VAR) <Compile the I6 Story constant 12.1>;
if (story_headline_VAR) <Compile the I6 Headline constant 12.2>;
if (story_author_VAR) <Compile the I6 Story Author constant 12.3>;
if (story_release_number_VAR) <Compile the I6 Release directive 12.4>;
<Compile the I6 serial number, based on the date 12.5>;
END_COMPILATION_MODE;
encode_constant_text_bibliographically = FALSE;
}
The function PL::Bibliographic::compile_constants appears nowhere else.
§12.1. If the author doesn't name a work, then its title is properly "", not "Welcome": that's just something we use to provide a readable banner.
<Compile the I6 Story constant 12.1> =
inter_name *iname = Hierarchy::find(STORY_HL);
NonlocalVariables::treat_as_plain_text_word(story_title_VAR);
inter_t v1 = 0, v2 = 0;
if (NonlocalVariables::has_initial_value_set(story_title_VAR))
NonlocalVariables::seek_initial_value(iname, &v1, &v2, story_title_VAR);
else
Strings::TextLiterals::compile_literal_from_text(iname, &v1, &v2, L"\"Welcome\"");
Emit::named_generic_constant(iname, v1, v2);
This code is used in §12.
<Compile the I6 Headline constant 12.2> =
inter_name *iname = Hierarchy::find(HEADLINE_HL);
inter_t v1 = 0, v2 = 0;
if (NonlocalVariables::has_initial_value_set(story_headline_VAR)) {
NonlocalVariables::treat_as_plain_text_word(story_headline_VAR);
NonlocalVariables::seek_initial_value(iname, &v1, &v2, story_headline_VAR);
} else {
Strings::TextLiterals::compile_literal_from_text(iname, &v1, &v2, L"\"An Interactive Fiction\"");
}
Emit::named_generic_constant(iname, v1, v2);
This code is used in §12.
§12.3. This time we compile nothing if no author is provided:
<Compile the I6 Story Author constant 12.3> =
if (NonlocalVariables::has_initial_value_set(story_author_VAR)) {
inter_name *iname = Hierarchy::find(STORY_AUTHOR_HL);
inter_t v1 = 0, v2 = 0;
NonlocalVariables::treat_as_plain_text_word(story_author_VAR);
NonlocalVariables::seek_initial_value(iname, &v1, &v2, story_author_VAR);
Emit::named_generic_constant(iname, v1, v2);
}
This code is used in §12.
§12.4. Similarly (but numerically):
<Compile the I6 Release directive 12.4> =
if (NonlocalVariables::has_initial_value_set(story_release_number_VAR)) {
inter_name *iname = Hierarchy::find(RELEASE_HL);
inter_t v1 = 0, v2 = 0;
NonlocalVariables::seek_initial_value(iname, &v1, &v2, story_release_number_VAR);
Emit::named_generic_constant(iname, v1, v2);
}
This code is used in §12.
§12.5. This innocuous code — if Inform runs on 25 June 2013, we compile the serial number "130625" — is actually controversial: quite a few users feel they should be able to fake the date-stamp with dates of their own choosing.
<Compile the I6 serial number, based on the date 12.5> =
inter_name *iname = Hierarchy::find(SERIAL_HL);
TEMPORARY_TEXT(SN);
int year_digits = (the_present->tm_year) % 100;
WRITE_TO(SN, "%02d%02d%02d",
year_digits, (the_present->tm_mon)+1, the_present->tm_mday);
Emit::named_text_constant(iname, SN);
DISCARD_TEXT(SN);
This code is used in §12.
§13. The Library Card is part of the Contents index, and is intended as a natural way to present bibliographic data to the user. In effect, it's a simplified form of the iFiction record, without the XML overhead.
void PL::Bibliographic::index_library_card(OUTPUT_STREAM) {
HTML_OPEN("p");
Index::anchor(OUT, I"LCARD");
HTML::begin_html_table(OUT, "*bg_images/indexcard.png", FALSE, 0, 3, 3, 0, 0);
PL::Bibliographic::library_card_entry(OUT, "Story title", story_title_VAR, I"Untitled");
PL::Bibliographic::library_card_entry(OUT, "Story author", story_author_VAR, I"Anonymous");
PL::Bibliographic::library_card_entry(OUT, "Story headline", story_headline_VAR, I"An Interactive Fiction");
PL::Bibliographic::library_card_entry(OUT, "Story genre", story_genre_VAR, I"Fiction");
if (episode_number >= 0) {
TEMPORARY_TEXT(episode_text);
WRITE_TO(episode_text, "%d of %w", episode_number, series_name);
PL::Bibliographic::library_card_entry(OUT, "Episode", NULL, episode_text);
DISCARD_TEXT(episode_text);
}
PL::Bibliographic::library_card_entry(OUT, "Release number", story_release_number_VAR, I"1");
PL::Bibliographic::library_card_entry(OUT, "Story creation year", story_creation_year_VAR, I"(This year)");
TEMPORARY_TEXT(lang);
WRITE_TO(lang, "%+W", NaturalLanguages::get_name(language_of_play));
PL::Bibliographic::library_card_entry(OUT, "Language of play", NULL, lang);
DISCARD_TEXT(lang);
PL::Bibliographic::library_card_entry(OUT, "IFID number", NULL, PL::Bibliographic::IFID::read_uuid());
PL::Bibliographic::library_card_entry(OUT, "Story description", story_description_VAR, I"None");
HTML::end_html_table(OUT);
HTML_CLOSE("p");
}
The function PL::Bibliographic::index_library_card appears nowhere else.
void PL::Bibliographic::library_card_entry(OUTPUT_STREAM, char *field, nonlocal_variable *nlv, text_stream *t) {
text_stream *col = I"303030";
if (nlv == story_title_VAR) col = I"803030";
HTML::first_html_column_nowrap(OUT, 0, NULL);
HTML::begin_colour(OUT, col);
HTML_OPEN_WITH("span", "class=\"typewritten\"");
WRITE("%s", field);
HTML_CLOSE("span");
HTML::end_colour(OUT);
HTML::next_html_column(OUT, 0);
HTML::begin_colour(OUT, col);
HTML_OPEN_WITH("span", "class=\"typewritten\"");
HTML_OPEN("b");
PL::Bibliographic::index_bibliographic_variable(OUT, nlv, t);
HTML_CLOSE("b");
HTML_CLOSE("span");
HTML::end_colour(OUT);
HTML::end_html_row(OUT);
}
The function PL::Bibliographic::library_card_entry is used in §13.
§15. The Index also likes to print the name and authorship at the top of the Contents listing, so:
void PL::Bibliographic::contents_heading(OUTPUT_STREAM) {
if ((story_title_VAR == NULL) || (story_author_VAR == NULL))
WRITE("Contents");
else {
PL::Bibliographic::index_bibliographic_variable(OUT, story_title_VAR, I"Untitled");
WRITE(" by ");
PL::Bibliographic::index_bibliographic_variable(OUT, story_author_VAR, I"Anonymous");
}
}
The function PL::Bibliographic::contents_heading appears nowhere else.
§16. And both of those features use:
void PL::Bibliographic::index_bibliographic_variable(OUTPUT_STREAM, nonlocal_variable *nlv, text_stream *t) {
BEGIN_COMPILATION_MODE;
COMPILATION_MODE_ENTER(COMPILE_TEXT_TO_XML_CMODE);
if ((nlv) && (NonlocalVariables::has_initial_value_set(nlv))) {
wording W = NonlocalVariables::treat_as_plain_text_word(nlv);
HTMLFiles::compile_bibliographic_text(OUT, Lexer::word_text(Wordings::first_wn(W)));
} else {
WRITE("%S", t);
}
END_COMPILATION_MODE;
}
The function PL::Bibliographic::index_bibliographic_variable is used in §14, §15.