Lenta

v0.11 This a work in progress. Written by User:Milcho.

Programs in Lenta consist in a two-dimensional grid of instructions, like Befunge, and operate on a tape of cells, like brainfuck. There is also an extra variable, the buffer, that can be accessed at all times.

Instructions

• Unary operators apply to the buffer.
• Binary operators take the current cell and the buffer as operands, and store result in the buffer.
• Logic operators read 0 and less as false, 1 and greater as true, and return 0 for false, 1 for true.
• Any character that is not a valid instruction is ignored.

Symbol	Operator
+	PLUS	Add buffer and current cell and store result in buffer.
-	MINUS	Subtract buffer from current cell and store result in buffer.
*	MULT	Multiply buffer and current cell and store result in buffer.
_	DIV	Divide current cell by buffer and store integer quotient in buffer.
%	MOD	Divide current cell by buffer and store remainder in buffer.
0	ZERO	Zero the buffer.
<	LESS	Store 1 in buffer if current cell is less than buffer, 0 otherwise.
>	GREATER	Store 1 in buffer if current cell is greater than buffer, 0 otherwise.
=	EQUAL	Store 1 in buffer if current cell is equal to buffer, 0 otherwise.
&	AND	Store 1 in buffer if both current cell and buffer are true, 0 otherwise.
|	OR	Store 1 in buffer if current cell or buffer is true, 0 if both are false.
!	NOT	If buffer is 0 or less, set it to 1; if it is 1 or greater, set it to 0.
Symbol	Instruction
$	START	Start program here, moving right.
[	LEFT	Move to previous cell.
]	RIGHT	Move to next cell.
{	N-LEFT	Move n cells to the left, where n is the value in the buffer.
}	N-RIGHT	Move n cells to the right, where n is the value in the buffer.
/	RULD	Reflect flow: right-up, left-down.
\	LURD	Reflect flow: left-up, right-down.
:	CEL<BUF	Overwrite current cell with a copy of the buffer.
;	BUF<CEL	Overwrite buffer with a copy of the current cell.
@	INDEX	Overwrite buffer with the location index of the current cell.
~	SWAP	Swap the buffer and current cell values.
'	OUT	Output the buffer as a character.
,	OUT	Output the buffer as an integer.
.	IN	Read an ASCII character or an integer from input, and store it in the buffer.
"	SET	Overwrite buffer with the ASCII value of the next character in the program (and skip it?).
?	SKIP	If the buffer is 0 or less (false), skip next valid instruction.
#	HALT	Halt execution.

Example programs

Those programs haven't been tested yet.

Hello, World!

$ "H'"e'"l' '"o'" '"W'"o'"r'"l'"d'"!' #

Addition

Read in two ints, add their values and print it, and loop until both ints are 0.

$ 0? / .:].:[+,0=:]0=[&!?\#
     \                   /

Fibonacci sequence

Read a number N, and print the first N Fibonacci numbers.

                            /    \
$ ]0: ]0!: [[  .:  0?/  ; ? / \  \ ] ; , ",' ] ; [ ~ + ] : [[ 0! - : \
                              #                                  
                     \                                               /

External links

• Interpreter in Python