// Phase 164: Test skip_whitespace from JsonParserBox (Pattern3 with if-else PHI + break)
// Simulates: loop(p < len) { if is_whitespace(ch) { p++ } else { break } }

static box Main {
  main(args) {
    // Simulate skipping leading whitespace
    local s = "   \t\nhello world"
    local p = 0
    local len = s.length()

    // Loop with if-else PHI: p is updated in both branches differently
    loop(p < len) {
      local ch = s.substring(p, p + 1)
      // Check if whitespace
      local is_ws = 0
      if ch == " " {
        is_ws = 1
      } else if ch == "\t" {
        is_ws = 1
      } else if ch == "\n" {
        is_ws = 1
      } else if ch == "\r" {
        is_ws = 1
      }

      if is_ws == 1 {
        p = p + 1
      } else {
        break
      }
    }

    // Output result
    local remaining = s.substring(p, len)
    print("Skipped leading whitespace")
    print("Position: " + ("" + p))
    print("Remaining: " + remaining)
    print("Expected position: 4")
    print("Expected remaining: hello world")
    return 0
  }
}