EDE

EDE (Esolang Defenition Esolang) is an esolang that every program defines an interpreter.

Brainfuck interpreter

define a pointer
define b string-ascii
----------
> moves a forward on b
< moves a backward on b
+ increases b at spot of a
- decreases b at spot of a
, replaces b at spot of a with input
. puts b at spot of a in output
[ goes to ] if b at spot of a is 0
] goes to [ if b at spot of a is !0

Deadfish interpreter

define a number
----------
i increases a
d decreases a
s squares a
q outputs a
----------
if a=256, a=0
if a=-1, a=0

Truth machine interpreter

----------
0 outputs 0
1 outputs 1
----------
when output 1, output 1

Conway's game of life interpreter

----------
----------
o touching 4o is b
o touching 7b is b
b touching 3o 5b is o
! ruletype=ca-moore !

my-new-esolang.txt interpreter

define a accumulator
define b temp
define c boolean
----------
P outputs rotate25 lowercase
I input to a
C input boolean to c
{ rotate1 a character
>b- if a is b
<b: if c is b
) goes to (