// Phase 133 P0: Promoted carrier join_id test (JsonParser._skip_whitespace pattern)
// 目的: Loop + promoted carrier の join_id 問題を検証・修正（Phase 133課題）
// Issue: promoted carrier 'is_char_match' has no join_id when break is used
// Pattern: [cond_promoter] A-3 Trim pattern promoted → [phase229] no join_id error
// Input: "   X" (3 spaces + character)
// Expected: return 3 (count of leading spaces before first non-space)
// Verification: exit code (VM: RC, LLVM EXE: exit code)

static box Main {
  countSpaces(s) {
    local count = 0
    local index = 0
    loop(index < s.length()) {
      local char = s.substring(index, index + 1)
      if char == " " {
        count = count + 1
        index = index + 1
      } else {
        break
      }
    }
    return count
  }

  main() {
    local input = "   X"
    return me.countSpaces(input)  // Expected: 3
  }
}