False

FALSE is an esoteric stack based language made in 1993 by Wouter van Oortmerssen. Its goals were to be a terse and powerful language with a minimal compiler. The original compiler was implemented in 1024 bytes using 68000 assembler. Despite its minimal compiler, FALSE supports features such as if operations, while loops, and anonymous functions (lambdas).

Additionally, FALSE allows for you to define up to 26 variables [a-z]. Further detail can be found on the esolang wiki for FALSE.

Code examples of FALSE:

{ Implementation of Factorial in FALSE
[$1=~[$1-f;!*]?]f:

{ Implementation of Fibonacci in FALSE }
{ Returns 0 if n <= 0                  }
[$0>~$[0@%\]?~[$1=$[1@%\]?~[$1-f;!\2-f;!+]?]?]f:

• esolang wiki
• The FALSE Programming Language
• FALSE Online Interpreter