hakorune/apps/selfhost-vm/mini_vm_if_branch.nyash

// Mini-VM: function-based entry for branching
// Local static box (duplicated from mini_vm_lib for now to avoid include gate issues)
static box MiniVm {
  _is_digit(ch) { return ch == "0" || ch == "1" || ch == "2" || ch == "3" || ch == "4" || ch == "5" || ch == "6" || ch == "7" || ch == "8" || ch == "9" }
  read_digits(json, pos) {
    local out = ""
    loop (true) {
      local s = json.substring(pos, pos+1)
      if s == "" { break }
      if _is_digit(s) { out = out + s  pos = pos + 1 } else { break }
    }
    return out
  }
  parse_first_int(json) {
    local key = "\"value\":{\"type\":\"int\",\"value\":"
    local idx = json.lastIndexOf(key)
    if idx < 0 { return "0" }
    local start = idx + key.length()
    return read_digits(json, start)
  }
  run_branch(json) {
    local n = parse_first_int(json)
    if n == "0" || n == "1" || n == "2" || n == "3" || n == "4" { print("10") return 0 }
    print("20")
    return 0
  }
}

// Program entry: embedded JSON (value=1 → print 10; else → 20)
static box Main {
  main(args) {
    local vm = new MiniVm()
    local json = "{\"kind\":\"Program\",\"statements\":[{\"kind\":\"Print\",\"expression\":{\"kind\":\"Literal\",\"value\":{\"type\":\"int\",\"value\":1}}}]}"
    // If provided, override by argv[0]
    if args {
      if args.size() > 0 {
        local s = args.get(0)
        if s { json = s }
      }
    }
    return vm.run_branch(json)
  }
}

// Top-level fallback entry for current runner
function main(args) {
  local vm = new MiniVm()
  local json = "{\"kind\":\"Program\",\"statements\":[{\"kind\":\"Print\",\"expression\":{\"kind\":\"Literal\",\"value\":{\"type\":\"int\",\"value\":1}}}]}"
  if args {
    if args.size() > 0 {
      local s = args.get(0)
      if s { json = s }
    }
  }
  local n = vm.parse_first_int(json)
  if n == "0" || n == "1" || n == "2" || n == "3" || n == "4" { print("10") return 0 }
  print("20")
  return 0
}