Footnotes, in standard literature, are textual asides or comments printed at the bottom of the page, signaled within the main body of the text by a matching superscripted number, an asterisk, a dagger symbol, or some other mark.
The equivalent feature in interactive fiction is uncommon, first appearing in Infocom's The Hitchhiker's Guide to the Galaxy (Douglas Adams and Steve Meretzky; 1984). The game indicates the existence of a footnote with a bracketed notation such as "(Footnote 14)". The player may then type the command FOOTNOTE 14 to read the footnote. Footnotes allow the author to provide extra information or commentary on what the player just read. Graham Nelson (in the DM4) describes Hitchhiker's use of footnotes as "puckish comedy".
Characteristics of footnotes
Footnotes in IF may be:
- pre-numbered or auto-numbered
- Hitchhiker's used pre-numbered footnotes, which permitted players to type "FOOTNOTE 1", "FOOTNOTE 2", etc. in order to read all the footnotes at will before ever being prompted to do so. This style encouraged subsequent authors to add fake footnotes or even booby-trapped fake footnotes to punish the player who cheats this way. It is generally preferred to use auto-numbered footnotes, so that whichever footnote is first encountered in a session becomes Footnote 1 and isn't readable until so encountered in the game.
- repeating, semi-repeating, or non-repeating
- Repeating footnotes display tags like "[Footnote 4]" unconditionally.
- Semi-repeating footnotes only display tags for footnotes that haven't been read yet.
- Non-repeating footnotes only display their tags once.
- enabled or disabled
- Some games permit the user to disable the footnotes with a FOOTNOTES OFF command.
- serious or comical
- Many footnotes are intentionally amusing, often informative (perhaps adding backstory to the game), but seldom are required reading to win the game. The vast majority of footnotes are optional bits of business.
Footnotes are signaled in the main text of the game by bracketed notations such as "" or "[Footnote 4]". Either square or round brackets might be used. Superscripting is generally not used because of limitations with either the standard authoring systems, the interpreters, or both.
A game with footnotes provides an extra implicit goal that the player can strive for: to find and read all the footnotes.
Possible avenues to explore for future authors include:
- displaying footnote marks with superscripted numbers (for those authoring systems and interpreters capable of displaying them),
- making the footnote marks clickable with the mouse,
- reserving a region on the bottom of the screen for displaying footnote text or displaying the footnote in a pop-up or tooltip, and
- auto-displaying the footnote text after all other text for that turn has been displayed, without requiring the player to type "FOOTNOTE 3" or any similar command.
There isn't really a standard set of player commands for managing footnotes, but these seem to be most common:
- FOOTNOTE number or NOTE number
- Displays the appropriate footnote.
- FOOTNOTES ON or NOTES ON
- Enables footnotes in the game.
- FOOTNOTES OFF or NOTES OFF
- Disables footnotes in the game.
Sometimes FOOTNOTE may be abbreviated to FN or F.
Sometimes FOOTNOTES informs the player whether or not footnotes are enabled.
Sometimes READ FOOTNOTE number or READ NOTE number will also display a footnote.
Some notable games with footnotes
- The Hitchhiker's Guide to the Galaxy (Douglas Adams and Steve Meretzky; publisher: Infocom; 1984; Z-code).
- First known work of interactive fiction to use footnotes.
- FIRST WAVE, Then Jump Up and Down Screaming (L. Ross Raszewski; 1999; Z-code).
- Frequent use of footnotes.
- Child's Play (Stephen Granade; 2006–2007; Z-code).
- Most games with footnotes enable them from the beginning, but Child's Play disables them entirely until you win the game, whereupon the game tells the player what secret command enables them. Thus the footnotes become a reward for winning.
- Yon Astounding Castle! of some sort (Duncan Bowsman; 2009; ADRIFT 4).
- Contains two varieties of footnotes: regular and puzzle. At certain points in the game, the player may be directed to look at, for example, Footnote 2, or Puzzle Footnote 6. The player should type FOOTNOTE 2 or PUZZLE FOOTNOTE 6 respectively to read them.
- Mentula Macanus: Apocolocyntosis (Adam Thornton as "One of the Bruces and Drunken Bastard"; 2010 and 2011; Glulx).
- Again, two types of footnotes, styled as footnotes and references. The commands "PONCY OFF" and "PONCY ON" toggle the display of footnotes; likewise, "BIBLIOGRAPHY OFF" and "BIBLIOGRAPHY ON" toggles display of references.
- Example 83 from the DM4.
- Footnote.h by L. Ross Raszewski.
- Library extension based on and expanded from the DM4 example. Cautions that the DM4 example will sometimes number the same footnote twice. Supports auto-numbered repeating footnotes. Output text strings are easy to replace for use with non-English languages.
- notes.h by Anson Turner.
- Library extension. Supports auto-numbered repeating footnotes. This is simpler than Raszewski's extension, but less flexible.
- footnotes.h in the Platypus replacement library for Inform 6 by Anson Turner is likely very similar to his notes.h extension.
- Example Ibid. in The Inform Recipe Book.
- Footnotes by Stephen Granade.
- Library extension originally created for Child's Play. Supports auto-numbered repeating or non-repeating footnotes which are by default disabled.