Triangular

Triangular is a two-dimensional stack-based esoteric programming language, inspired by Surface and Hexagony. Source code is read in the shape of the smallest triangle that the length of the code can fit into. Whitespace is ignored. For example, if the source code was 123456, Triangular would format this into:

  1
 2 3
4 5 6

To build, type make. This will generate an executable triangular. Command-line options:

--verbose                     prettyprint the triangle
--display-code                display code as it's read

Triangular has:

• A stack size of 30,000
• A maximum of 300 jumps
• A maximum source code of 1000 lines, 1000 characters per line
• A second stack (see section Memory), which is currently just one value.

Acronyms: ToS = top of stack, IP = instruction pointer

There are eight directions in which the IP can move (the IP is located at .):

    2  
   1 3
  8 . 4
   7 5
    6

(. is a no-op.)

The directional numbers correspond to the cardinal directions and their combinations like so:

1 NorthWest  `
2 North      ^
3 NorthEast  /
4 East       >
5 SouthEast  \
6 South      v
7 SouthWest  ,
8 West       <

Visualization of directional switches:

   ^
  ` /
 < . >  
  , \
   v

IP starts from the top of the triangle, moving in direction 5 (SE).

    \
     .
    . .
   . . .
  . . . .
 . . . . .

If the IP goes off the playing field, the program will terminate.

Commands

IP switches

` switch to direction 1 (NW)
^ switch to direction 2 (N)
/ switch to direction 3 (NE)
> switch to direction 4 (E)
\ switch to direction 5 (SE)
v switch to direction 6 (S)
, switch to direction 7 (SW)
< switch to direction 8 (W)
o rotate the direction of the IP clockwise
e rotate the direction of the IP counter-clockwise
c rotate the direction of the IP clockwise, then become z
z rotate the direction of the IP counter-clockwise, then become c

Program commands

& end program

Stack commands

p pop
: duplicate ToS
+ add ToS to ToS-1, pop both, push result
- subtract ToS from ToS-1, pop both, push result
* multiply ToS and ToS-1 together, pop both, push result
_ divide ToS-1 by ToS, pop both, push result
= compare ToS and ToS-1 for equality, DON'T pop, push result
d decrement ToS
i increment ToS
0 push 0 to stack. 1 pushes 1, 2 pushes 2, etc.
A push 10 to stack. B pushes 11, etc. up to F.
" swap top two stack values
l push 1 if ToS-1 < ToS, otherwise 0, discard values used
g push 1 if ToS-1 > ToS, otherwise 0, discard values used
| negate ToS (positive -> negative, negative -> positive)
u un-sign ToS (negative -> positive)
m divide ToS-1 by ToS, pop both, push remainder

I/O commands

$ input ToS as a number
~ input ToS as a character
% print ToS as integer
@ print ToS as character
# print ToS as character and pop

Memory commands

P pop ToS stack to memory
S stash ToS in memory
U pull memory to stack

Conditionals (stolen directly from Surface)

? skip one instruction in the direction the IP is facing if ToS is <= 0
! skip one instruction in the direction the IP is facing if ToS is > 0
s skip the quantity of following instructions as specified by the number contained in ToS
( set a point to be jumped to by ) and ]
) unconditionally move the instruction pointer back to the most recent (
] move the instruction pointer back to the most recent ( if the ToS is > 0, otherwise do away with the most recently accumulated (
x do away with the most recently accumulated (
; end program if ToS <= 0

Unused characters

'[{}abfhyGHIJKLMNOQRTVWXYZ