Windy

A 2D esoteric language where code flows like wind. GitHub · SPEC

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      Opcode reference (35 opcodes — click to expand)
      

        Every cell is one Unicode codepoint. Outside string mode, the IP
        decodes its current cell as one of these opcodes; inside string
        mode (toggled by ") every cell except "
        pushes its codepoint to the stack instead.
      

      

        

          
            
CatGlyphNameEffect

          
          
            
Flow  ·NOPDo nothing.

            
Flow@HALTRemove the executing IP from the live list. When empty, the program ends.

            
Flow#TRAMPOLINEAdvance an extra step (skip the next cell).

            
FlowtSPLITSpawn a new IP at (x − dx, y − dy) going (−dx, −dy); empty stack, strmode off.


            
Wind→ >MOVE_Edir ← (+1, 0)

            
Wind↗MOVE_NEdir ← (+1, −1)

            
Wind↑ ^MOVE_Ndir ← (0, −1)

            
Wind↖MOVE_NWdir ← (−1, −1)

            
Wind← <MOVE_Wdir ← (−1, 0)

            
Wind↙MOVE_SWdir ← (−1, +1)

            
Wind↓ vMOVE_Sdir ← (0, +1)

            
Wind↘MOVE_SEdir ← (+1, +1)

            
Wind~TURBULENCEPick a random direction from the eight winds. Use --seed for reproducibility.


            
Speed≫GUSTspeed += 1. The IP advances speed cells per tick; only the destination decodes.

            
Speed≪CALMspeed −= 1; runtime trap (exit 134) if it would yield 0.


            
Lit0…9PUSH_DIGITPush the digit's integer value (0–9).

            
Lit"STR_MODEToggle string mode.


            
Arith+ADDb ← pop; a ← pop; push a + b

            
Arith−SUBpush a − b

            
Arith*MULpush a × b

            
Arith/DIVFloor division. b == 0 ⇒ push 0.

            
Arith%MODFloor modulo. b == 0 ⇒ push 0.

            
Arith!NOTpush 1 if a == 0 else 0

            
Arith`GTpush 1 if a > b else 0


            
Stack:DUPDuplicate the top.

            
Stack$DROPDiscard the top.

            
Stack\SWAPSwap the top two.


            
Branch_IF_Ha ← pop; dir ← east if a == 0 else west

            
Branch|IF_Va ← pop; dir ← south if a == 0 else north


            
I/O.PUT_NUMPop, write decimal repr followed by a space.

            
I/O,PUT_CHRPop codepoint, write as a Unicode character.

            
I/O&GET_NUMRead one decimal integer from stdin (EOF → −1).

            
I/O?GET_CHRRead one Unicode character; push codepoint (EOF → −1).


            
GridgGRID_GETy ← pop; x ← pop; push G[(x, y)] (missing ⇒ 0x20).

            
GridpGRID_PUTy ← pop; x ← pop; v ← pop; G[(x, y)] ← v


          
        

      

      

        Stack underflow yields 0 (no trap). Pop from empty,
        divide by zero, and unknown glyphs are all explicitly defined —
        see SPEC §7.
      

      

        Each IP carries a positive-integer speed (default 1)
        and advances speed cells per tick — only the
        destination cell decodes (SPEC §3.7).
        End-of-tick coincidence triggers a
        collision merge
        (§3.8): stacks concatenate in birth order, directions sum and
        clip ((0,0) ⇒ merged IP dies), speed becomes
        max, strmode resets. Toggle v0 legacy
        in the toolbar to disable both and reproduce the v0.4 surface.