type font_layout_data = {
    font_ascent: int;
    font_descent: int;
    font_leading: int;
    font_glyphs_layout: font_layout_glyph_data array;
    font_kerning: font_kerning_data list;
}

    {
            font_ascent = snip
            font_descent = snip
            font_leading = snip
            font_glyphs_layout = snip
            font_kerning = !kerning;
    }

Error: This expression has type Swf.font_layout_data but is here used with type unit.