// without types and proper AOT parsing

srecord noeq GazelleVScript(S text) {

  LS tok;

  sS helpText = !include string #1033775;

  // A sequence is a sequence of runs,

  // for example in an animation

  class Sequence {

    new MapSO vars;

  }

  class Run is Steppable {

    ListAndIndex<S> ptr; // where are we in the script

    S token;

    new Stack stack;

    // main variables

    settable IBWIntegralImage inputImage;

    IBWIntegralImage integralImage;

    settable BWImage bwImage;

    selfType setIntegralImage(IBWIntegralImage ii) {

      push(integralImage = ii);

      this;

    }

    *() {

      parse();

      ptr = ListAndIndex(tok, 1);

    }

    void push(O o) { stack.add(o); }

    O value() { ret last(stack); }

    public bool step() {

      token = ptr!;

      if (token == null) false;

      next();

      if (isInteger(token)) {

        int i = parseInt(token);

        token = tpp();

        if (is("p"))

          scaleToHeight(i);

        else if (is("c"))

          posterize(i);

        else if (is("w"))

          scaleWidthOnly(i);

        else

          warn("Unknown token: " + token);

      } else if (is("rasters"))

        push(reproduceRasterBars(bwIntegralImage()));

      else if (is("struct"))

        push(struct(value()));

      else if (is("niceStruct"))

        push(sfuIndent(value()));

      else if (is("className"))

        push(className(value()));

      else if (is("borderImage"))

        push(bwImage = gazelle22_borderImage(bwImage));

      else if (is("gradientImage"))

        push(bwImage = new Gazelle22_GradientImage(bwImage)!);

      else if (is("q1")) clip(0, .5, 0, .5);

      else if (is("q2")) clip(.5, 1, 0, .5);

      else if (is("q3")) clip(0, .5, .5, 1);

      else if (is("q4")) clip(.5, 1, .5, 1);

      else if (is("original"))

        push(toBufferedImage(inputImage));

      else {

        warn("Unknown token: " + token);

      }

      true;

    }

    bool is(S t) { ret eqic(token, t); }

    S tpp() { var token = ptr!; next(); ret token; }

    void next { if (!ptr.atEnd()) ptr = ptr.plus(2); }

    // operations

    void scaleToHeight(int pixelRows) {

      pixelRows = min(pixelRows, 512);

      if (integralImage == null)

        ret with warn("No integral image to scale down");

      push(bwImage = scaledBWImageFromBWIntegralImage_withMeta_height(pixelRows, integralImage));

    }

    void posterize(int colors) {

      colors = clamp(colors, 2, 256);

      if (bwImage == null)

        ret with warn("No image to posterize");

      else

        push(bwImage = posterizeBWImage_withMeta(colors, bwImage));

    }

    IBWIntegralImage bwIntegralImage() {

      O val = value();

      if (val cast IBWIntegralImage) ret val;

      if (val cast BWImage) {

        var ii = main bwIntegralImage(val);

        setIntegralImage(ii);

        ret ii;

      }

      fail("Not an image on stack");

    }

    void scaleWidthOnly(int w) {

      var ii = bwIntegralImage();

      push(bwImage = scaledBWImageFromBWIntegralImage_withMeta(

        ii, w, ii.getHeight());

    }

    void clip(double x1, double x2, double y1, double y2) {

      O val = value();

      if (val cast IBWIntegralImage) {

        int w = val.getWidth(), h = val.getHeight();

        Rect r = toRect_round(scaleRect(w, h,

          doubleRectFromPoints(x1, y1, x2, y2)));

        setIntegralImage(new IIBWVirtualClip(val, r));

      }

      else if (val cast BWImage)

        todo();

      else fail("Not an image on stack");

    }

    // end of operations

    O result() {

      ret last(stack);

    }

    run { stepAll(this); }

  }

  void parse() {

    tok if null = javaTok(text);

  }

}