emd

emd

Paradigm(s)	imperative
Designed by	User:Lupodevelop
Appeared in	2026
Memory system	stack-based, with memory cells
Dimensions	one-dimensional
Computational class	Turing complete
Reference implementation	emd (Rust)
File extension(s)	.emd

emd (short for em dash, also known as Emotional damage) is a stack-based language written only in eight Unicode dashes. Each pair of dashes is one instruction. In most fonts the dashes look alike, so a program reads as one long line of dashes.

Syntax

Index	Symbol	Code point	Name
0	-	U+002D	HYPHEN-MINUS
1	‐	U+2010	HYPHEN
2	‑	U+2011	NON-BREAKING HYPHEN
3	‒	U+2012	FIGURE DASH
4	–	U+2013	EN DASH
5	—	U+2014	EM DASH
6	―	U+2015	HORIZONTAL BAR
7	−	U+2212	MINUS SIGN

A source holds only these eight symbols and newlines. A line holds at most 32 symbols. Newlines are removed before decoding, so a break can fall anywhere, even inside an instruction. Any other character, including a look-alike dash, is an error.

An instruction is a pair: the first symbol picks the family, the second the operation. 32 of the 64 pairs are assigned; the others are decoding errors, not no-ops.

Instructions

b is the top of the stack, a the value below it.

Code	Name	Effect
- + symbol n	PUSH n	→ n, for n from 0 to 7
‐-	DUP	a → a a
‐‐	DROP	a →
‐‑	SWAP	a b → b a
‐‒	OVER	a b → a b a
‐–	ROT	a b c → b c a
‑-	ADD	a b → a+b
‑‐	SUB	a b → a−b
‑‑	MUL	a b → a·b
‑‒	DIV	a b → a/b truncated; fault if b=0
‑–	MOD	a b → remainder with the sign of a; fault if b=0
‒-	LOAD	a → M[a]
‒‐	STORE	v a →, M[a] := v
–-	JMP	off →, pc += off
–‐	JZ	c off →, jump if c=0
–‑	JNZ	c off →, jump if c≠0
–‒	HALT	stop
––	CALL	off → pc+1, pc += off
–—	RET	a →, pc := a
—-	READ	→ byte, or −1 at end of input
—‐	WRITE	v →, output byte v (0–255)
―-	EQ	a b → 1 if a=b, else 0
―‐	LT	a b → 1 if a < b, else 0
―‑	GT	a b → 1 if a > b, else 0
―‒	NOT	a → 1 if a=0, else 0

• There are no constants above 7; larger numbers are built with arithmetic (104 = 7·7·2+6).
• Jump offsets count instructions, relative to the jump itself. RET takes an absolute address, the one CALL pushed.
• Memory cells are indexed by naturals and start at 0. A negative address is a fault.
• Running past the end is a fault: programs end with HALT.
• The implementation uses 64-bit integers; overflow is a fault.

Examples

Print h (PUSH 7, DUP, MUL, PUSH 2, MUL, PUSH 6, ADD, WRITE, HALT):

-−‐-‑‑-‑‑‑-―‑-—‐–‒

Cat program:

—-‐---―‐-‐-−‑‑-‒‑-–‑—‐---‑-−‑‑-–
‑-‑‐–-–‒

Truth-machine:

—-‐--‐‑--‐-−‑‑-‒‑-–‐‐-—‐‐--−-−‑‑
―--‑–‑–‒‐-—‐---—‑‐–-

Hello, world!:

-‐-−‑‑-‒‑--−‑‑-‑‑-—‐-‑-−‑‑-−‑‑-‒
‑-—‐-‑-−‑‑-‐‑--−‑‑-‒‑-—‐-‑-−‑‑-‐
‑--−‑‑-‒‑-—‐-‑-−‑‑-‐‑--−‑‑-―‑-—‐
-―-−‑‑-‑‑-—‐-–-−‑‑-–‑-—‐-‑-−‑‑-‒
‑--−‑‑—‐-‑-−‑‑-‐‑--−‑‑-―‑-—‐-‑-−
‑‑-‑‑--−‑‑-‑‑-—‐-‑-−‑‑-‐‑--−‑‑-‒
‑-—‐-‑-−‑‑-−‑‑-‑‑-—‐-–-−‑‑-—‑-—‐
-‐-−‑‑-‒‑-—‐–‒

Computational class

emd is Turing complete. A direct simulation of Turing machines using 11 of the instructions is proved in Lean 4 and Rocq, with unbounded integers and memory.

emd can also be translated to 3-cell brainfuck:

brainfuck	emd
Start of program	------
+	-‐‑-
-	-‐‑‐
>	‐–
<	‐–‐–
[	‐-e–‐, where e is a construction for the amount of instructions in the loop plus two.
]	‐-e–‑, where e is a construction for the amount of instructions in the loop.

Implementations

The reference implementation, in Rust, has an interpreter, a readable assembler, a reversible debugger, a static analyzer and a C backend. The assembler is also written in emd and compiles itself to the same bytes as the Rust one.

External resources

• GitHub repository
• Try it in the browser
• Paper: language, semantics and verification