// Phase 200-D: Digits accumulation test (no body-local in condition)
// This test verifies captured variable (digits) with string accumulation
// without requiring Pattern 5 body-local promotion.
//
// Key constraints:
// - Loop condition uses only LoopParam (p) and OuterLocal (n)
// - No body-local variables in break/if conditions
// - digits is captured and used in loop body

static box Main {
    main() {
        local digits = "0123456789"  // Captured var
        local s = "abc"              // Input string

        local p = 0
        local result = ""
        local n = s.length()  // n = 3

        // Simple loop: iterate exactly n times
        loop(p < n) {
            local ch = s.substring(p, p + 1)

            // Use digits to check if char is a digit (result not used in condition)
            local is_digit = digits.indexOf(ch)  // digits: captured

            // Always append the char (no conditional break)
            result = result + ch
            p = p + 1
        }

        print(result)  // Expected: "abc"
    }
}