ΙΧΘΥΣ / ἰχθῦς / ixqus

• νεκροΐχθυς (deadfish)
• ἀρχαῖος ἰχθῦς (ancient fish)
• παλαιός ἰχθῦς (old fish)
• γάρος (aged, fermented fish)
• ἰχθῦς σηπτός (rotten fish)

ΙΧΘΥΣ means 'fish' in Classical Greek. It is a derivative of firefly431's Deadfish x, and therefore a superset of Jonathan Todd Skinner's original Deadfish.

Motivation

I wanted to experiment with creating a reduced instruction set esoteric (+joke) programming language that made use of archaic languages and alphabets (yay Unicode!). Deadfish seemed an appealing base, and Deadfish x seemed like a powerful extension by adding 'functions', even though I don't believe they are functions in a strict sense.

ΙΧΘΥΣ Commands

letter	term	action	CAPITAL	CAPITAL action
ι	ἵστημι (raise / set up)	x+1	Ι	Begin statement def
χ	χάζω (draw back)	x-1	Χ	Set x to 0
θ	Θʹ (9) a square number	x*x	Θ	End statement def (Θέτε! / Make!)
υ	ὑπάγω (bring forth)	display x	Υ	display x as Unicode character
ς	σύμβολον (symbol/token)	N/A	Σ	N/A

Details, and modifications from Deadfish x:

• Reinstates the original Deadfish 'overflow' arithmetic behaviour (reset to 0 iff accumulator equals -1 OR 256). It is a feature, not a bug. Essential to allow values over 256 and enable the Unicode output required by ΙΧΘΥΣ.
• Output is Unicode, not ASCII.
• Does not refer to the definable 'functions' (The X command in Deadfish X, Ι in ΙΧΘΥΣ) as 'functions' since they take no arguments, return no results, and can only produce side-effects. In ΙΧΘΥΣ they are called 'statements', and have a number of important features, listed below.
• Adds a dedicated symbol (sigma) for labelling new statements.
• Statements are a collection of one or more statement symbols associated with a symbol, 'ς'.
• There is no execute command (Deadfish x C) required to trigger a defined statement, ΙΧΘΥΣ simply interprets the symbol if it can find a definition.
• Statement definitions can be nested.
• Statements definitions can be recursive.
• Statement symbols can be read before they are defined (or after they have been removed). There is no error on unrecognised symbols, simply a NOOP.
• Appying subsequent satement definitions (Ι) to an existing symbol appends to the statement definition, not overwrites.
• A statement definition is removed from storage if the Deadfish 'overflow' condition is triggered while reading from its definition. Only the symbol definition is removed, no action is taken with copies currently being read.
• Built-in command definitions are not appendable or removable, but they can be overwritten with new statement definitions that use the original command symbol.

Architecture

• A counting board (abacus) and pebbles to track the tally. (accumulator: x)
• A large pithos (storage jar) to store inscribed ostraka (clay fragments)
• A stack of papyrus sheets to track current symbols (primary storage)
• A line in the sand creating two rows, (2 register stacks)
  • one above for a list of ostraka currently being read
  • the other below for a list of ostraka currently being written
• A magic fish that can manifest Unicode specification characters

Other equipment: A sharp point for inscribing ostraka, a reed pen and ink for transcribing to papyrus, a wooden stick for drawing σύμβολα in the sand, many blank potsherds, a pile of extra abacuses and stones (for θ), wine.

Procedure: The slave/scribe (δοῦλος) begins with a sheet of papyrus, already containing some symbols. ... TODO: expand this section ... New statements are inscribed on ostraka, assigned a symbol (sigma) and placed in the pithos.

Examples

"Hello, World!" (direct port from the Deadfish x version)

ιιθιιιιθιιιιιιιιΥΧιιθιιιιιιθιΥιιιιιιιΥΥιιιΥΧιιιιιιιθχχχχχΥΧιιιιιιθχχχχΥΧιιιθιιθχχΥχχχχχχχχΥιιιΥχχχχχχΥχχχχχχχχΥΧιιιιιιθχχχΥ

OUTPUT: Hello, world!

Alphabet (Latin), again ported, but compressed, from Deadfish x example:

ΙΣιΥΘιιθιιιιθΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣ

OUTPUT: ABCDEFGHIJKLMNOPQRSTUVWXYZ

With its Unicode support, ΙΧΘΥΣ can just as easily display the Greek alphabet

XΙΣιΥΘιιιιιθιιιιιθιιιιιιιιιιιιΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣιΣΣΣΣΣΣΣ

OUTPUT: ΑΒΓΔΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΩ

And is not just limited to Greek, but can output from any Unicode block, for example, in Phoenician:

ΧΙΣιΥΘΙσχχχχχχχχχχχχχχχχχχχχχχχχχχχχΘιιιθιιιιιιιιθσθχχσσσσσσσσσσΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣΣ

OUTPUT: 𐤀𐤁𐤂𐤃𐤄𐤅𐤆𐤇𐤈𐤉𐤊𐤋𐤌𐤍𐤎𐤏𐤐𐤑𐤒𐤓𐤔𐤕

Non-Latin charset "Hello World"s

A more representative example for ΙΧΘΥΣ is to print 'Hello World' in Classical Greek:

ΙΣΧιιιιιθιιιιιιθΘΙϛχχχχχχχΘΙσϛϛιΘΙϲιιιιιιιιΘΣσσΥϲιιΥϲΥϲΥισΥΧιιθιιθϲΥΣσσσΥϲϲϲϲϲχχχΥιιιιΥϛΥϛΥΧιιιιιθϲΥ

OUTPUT: Χαιρε,Κοσμε!

Deadfish interpreter in ΙΧΘΥΣ

Since ΙΧΘΥΣ is a superset of Deadfish, it is relatively trivial to create a compliant Deadfish interpreter, e.g. for standard "idso" version:

ΙiιΘΙdχΘΙsθΘΙoυΘΧ

File Extension

The official file extension for ΙΧΘΥΣ code is .ἰχ, U+1F30 U+03C7, not to be confused with the letters ix.

The SYNTAX ERROR

There is only one form of syntax error in ΙΧΘΥΣ. Any line terminated with a sigma / σύμβολον character that is not a final-form sigma will result in a SYNTAX ERROR. On encountering such a SYNTAX ERROR, it may be challenged by an argument referencing at least one published academic article from the fields of classical studies, epigraphy, philology, or even less plausibly, computer science etc.

This does not mean lines have to end in a sigma, simply that if they do, they must be of an appropriate final form.

valid

>> ΙΣιιιυΘΣ
3

>> ΙςιιιυΘς
3

invalid

>> ΙσιιιυΘσ
?SYNTAX ERROR

The Non-Aristotelian Syllogism

• All Unicode code points can be represented by ΙΧΘΥΣ, except Ā, Latin Capital Letter A With Macron (U+0100).
• Ā, 'Null-A', refers to non-Aristotelian logic. ¹
• Therefore, ΙΧΘΥΣ cannot represent non-Aristotelian logic.

Localisation

Computational Class