Method push

src/main/java/net/starlark/java/eval/Printer.java:262–277

(Object x)

  // Reports whether x is already present on the visitation stack, pushing it if not.
  private boolean push(Object x) {
    // cyclic?
    for (int i = 0; i < depth; i++) {
      if (x == stack[i]) {
        return false;
      }
    }

    if (stack == null) {
      this.stack = new Object[4];
    } else if (depth == stack.length) {
      this.stack = Arrays.copyOf(stack, 2 * stack.length);
    }
    this.stack[depth++] = x;
    return true;
  }

  private void pop() {
    this.stack[--depth] = null;