COW

The COW programming language is an esoteric programming language created by Sean Heber in 2003. It is a Brainfuck variant designed humorously with Bovinae in mind. COW has twelve instructions (four more than Brainfuck) and is Turing-complete. Most instructions are moos, only the capitalization varies: mOo, moO, mOO, Moo, and so on. MMM, OOO, oom and OOM are the exceptions. All other character combinations are ignored and treated as comments.

Commands

Instruction	Description
moo	This command is connected to the MOO command. When encountered during normal execution, it searches the program code in reverse looking for a matching MOO command and begins executing again starting from the found MOO command. When searching, it skips the instruction that is immediately before it (see MOO).
mOo	Moves current memory position back one block.
moO	Moves current memory position forward one block.
mOO	Execute value in current memory block as if it were an instruction. The command executed is based on the instruction code value (for example, if the current memory block contains a 2, then the moO command is executed). An invalid command exits the running program. Value 3 is invalid as it would cause an infinite loop.
Moo	If current memory block has a 0 in it, read a single ASCII character from STDIN and store it in the current memory block. If the current memory block is not 0, then print the ASCII character that corresponds to the value in the current memory block to STDOUT.
MOo	Decrement current memory block value by 1.
MoO	Increment current memory block value by 1.
MOO	If current memory block value is 0, skip next command and resume execution after the next matching moo command. If current memory block value is not 0, then continue with next command. Note that the fact that it skips the command immediately following it has interesting ramifications for where the matching moo command really is. For example, the following will match the second and not the first moo: OOO MOO moo moo
OOO	Set current memory block value to 0.
MMM	If no current value in register, copy current memory block value. If there is a value in the register, then paste that value into the current memory block and clear the register.
OOM	Print value of current memory block to STDOUT as an integer.
oom	Read an integer from STDIN and put it into the current memory block.

Sample code

Hello, World!

 MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO
 MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO
 MoO MoO Moo MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO Moo MoO MoO
 MoO MoO MoO MoO MoO Moo Moo MoO MoO MoO Moo OOO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO
 MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO Moo MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO
 MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO
 MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO
 MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO Moo MOo
 MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo MOo
 MOo MOo MOo MOo MOo Moo MOo MOo MOo MOo MOo MOo MOo MOo Moo MoO MoO MoO Moo MOo MOo MOo MOo MOo MOo Moo MOo MOo MOo MOo MOo MOo MOo MOo Moo
 OOO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO MoO Moo 

This also prints "Hello, World!" but uses loops and the register to lead to a much shorter program:

 MoO MoO MoO MoO MoO MoO MoO MoO MOO moO MoO MoO MoO MoO MoO moO MoO MoO MoO MoO moO MoO MoO MoO MoO moO MoO MoO MoO MoO MoO MoO MoO
 MoO MoO moO MoO MoO MoO MoO mOo mOo mOo mOo mOo MOo moo moO moO moO moO Moo moO MOO mOo MoO moO MOo moo mOo MOo MOo MOo Moo MoO MoO 
 MoO MoO MoO MoO MoO Moo Moo MoO MoO MoO Moo MMM mOo mOo mOo MoO MoO MoO MoO Moo moO Moo MOO moO moO MOo mOo mOo MOo moo moO moO MoO 
 MoO MoO MoO MoO MoO MoO MoO Moo MMM MMM Moo MoO MoO MoO Moo MMM MOo MOo MOo Moo MOo MOo MOo MOo MOo MOo MOo MOo Moo mOo MoO Moo 

Fibonacci sequence

 MoO moO MoO mOo MOO OOM MMM moO moO
 MMM mOo mOo moO MMM mOo MMM moO moO
 MOO MOo mOo MoO moO moo mOo mOo moo

See also

Similar languages:

• Whirl

External resources

COW - Programming For Bovines (from the Wayback Machine; retrieved on 3 April 2013)

COW github.io

COW on Github contains interpreters/compilers in C++ and K.

COW online interpreter in Javascript

C# COW byte-code compiler and interpreter on github