#multicoding

To bake a Hello World Souffle requires exactly 114 g sugar, 111 ml beaten eggs, 54 ml double cream, and 32 g cocoa powder. Most recipes measure by the number of eggs, rather than their volume in milliliters, and do not opt for a level of specificity appropriate more for a chemistry lab than a kitchen. However, this recipe is not only for cooking, but also serves as a computer program in the Chef language.

Chef is one of the best-known esolangs to embrace multicoding: where content has different meanings when considered in different contexts. The term (as "multiple coding") was coined by Michael Mateas and Nick Montfort in their "A Box, Darkly" (2005), the paper that first introduced many academics to esoteric and obfuscated coding practices. It uses the example of "Jean put dire comment on tap," a phrase that holds very different meanings in French and English. Programs can be multicoded on a few different levels. Malicious programs are sometimes written with a gap between its reading by a human and its actual execution by the machine. In our previous post, we looked at the case of Primify, which multicodes numbers and images. Programs known as polyglots have a single text that holds multiple meanings even to the machine itself, functioning differently when interpreted in more than one programming language.

When Chef appeared in 2003, it joined a slowly growing list of esolangs that are explicitly multicoding, although this term was not one used by their creators (they are usually simply described as "designed to make programs appear to be something else"). Its author, David Morgan-Mar (interviewed here), created the cult esolang Piet the previous year. Where Chef's programs multicode as cooking recipes, programs in Piet (pronounced "Pete") are images, with commands defined by the change in hue or lightness between adjacent pixelly blobs of color, called codels. Shakespeare (created 2001) has as its programs, long, rambling stage scripts. Whitespace (2003) uses only tab, space, and return. In Whitespace, commands are multicoded as what is normally read as their absence. These characters are treated interchangeably by C and C-derived languages, meaning Whitespace programs can be embedded between words in these programs, creating polyglot programs that function in both languages.

There were few precursors for these languages in the early '00s. Previous esolangs like brainfuck and Malbolge had unusual lexicons, but emphasized their puzzle-like logic. Multicoding languages don't generally have unusual logical systems, most are straightforward, procedural languages behind their odd vocabularies. More recent multicoding languages, like AshPaper and bodyfuck, have benefited from these forerunners, learning the lessons of how Shakespeare commands are constructed as dialogue. But at the time Shakespeare was written, it was intended primarily as both joke and provocation. Its creators likely had little expectation that esoprogrammers would continue to work with these languages and learn from them decades later. Otherwise, there would be alternatives to Shakespeare's repetitive "SPEAK YOUR MIND!" command. So it might seem unfair to overly critique their design decisions, but considering Chef's design more deeply can give us insight into how multicoding schemes function and help consider possibilities in multicoding strategies for future works.

Primify takes an image and embeds it into a prime number, so that, when viewed from a distance, it resembles the original image. It was created by Levi Borodenko, a masters student in mathematics and statistics at the University of Oxford. While it works particularly well for logos and simple line art, was actually first developed for portraits.

The idea came while I was a counselor at PROMYS -- a summer camp providing an immersion into rigorous mathematics. We had a secret Santa and me being a poor student, I tried to come up with a gift idea that would light a maths majors heart without being pricey. So I decided to find a prime that looked like the face of the person that I had to gift. I coded up a quick and dirty script (back then I was using python to find the number and then mathematica to find the next prime). After doing this for a few years I decided that more people should be able to enjoy generating these primes. This is when I coded up the open-source tool.

In primify, the underlying data is not only used in a graphical way, but also holds information when read as text; in this case, a single prime number. This is multicoding, where content holds multiple meanings when read in different systems. It's a strategy familiar not only from esolangs like legit, which multicodes between git commands and code, and polyglots, where one program executes successfully in multiple programming languages. The strategy here, where the text functions as a picture, is more akin to how multicoding functions in obfuscated code that builds on concrete poetics, where the opacity of the code is offset with a visual clue as to its function. We can see this in the example cited here by Adrian Cables, or the cauldron example in this post about the IOCCC. The term multicoding comes from the seminal paper on esolangs and code art, "A Box Darkly" by Matteas and Montfort (as "multiple coding").