a turing machine in clickhouse?

turing.sql

WITH RECURSIVE turing AS (
    SELECT 
      [
        ('RSET', 3, 42),    -- Register SET (register#, int val): set register #LHS to value in RHS
        ('PASS', 0, 0),     -- is no-op
        ('IADD', 2, 2),     -- Integer ADD (register#, int val): add the value in RHS to the register #LHS
        ('RGTE', 2, 3),     -- Register Greater Than or Equal (register#, register#): sets the comparison register (register #1) to truthy if register #LHS is >= register #RHS
        ('CJMP', 7, 0),     -- Conditional JuMP: jump to the program index #LHS if the comparison register (register #1) is truthy (> 0)
        ('UJMP', 2, 0),     -- Unconditional JUMP: jump to the program index #LHS (here never reached)
        ('STOP', 0, 0)      -- STOP: stop the VM (terminates the request)
      ] AS program,
      0::UInt64 AS pcounter,
      [0::UInt64, 0, 0, 0] AS registers,
      0::UInt64 AS steps
UNION ALL
    SELECT
      program,
      multiIf(
        program[pcounter].1 == 'UJMP', program[pcounter].2,
        program[pcounter].1 == 'CJMP', if(registers[1] > 0, program[pcounter].2, pcounter+1),
        pcounter+1
      ) AS pcounter,
      multiIf(
        program[pcounter].1 == 'RSET', arrayMap((i, r) -> if(i == program[pcounter].2, program[pcounter].3, r), arrayEnumerate(registers), registers),
        program[pcounter].1 == 'IADD', arrayMap((i, r) -> if(i == program[pcounter].2, r+program[pcounter].3, r), arrayEnumerate(registers), registers),
        program[pcounter].1 == 'RMOV', arrayMap((i, r) -> if(i == program[pcounter].2, registers[program[pcounter].3], r), arrayEnumerate(registers), registers),
        program[pcounter].1 == 'RGTE', arrayMap((i, r) -> if(i == 1 /*bool-ish register for conditional instructions*/, registers[program[pcounter].2] >= registers[program[pcounter].3], r), arrayEnumerate(registers), registers),
        registers
      ) AS registers,
      steps+1 AS steps
    FROM turing
    WHERE program[pcounter].1 <> 'STOP' AND steps < 1000
)
SELECT
  program[pcounter] AS instruction,
  registers AS registers_after,
  pcounter AS program_counter
FROM turing;