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//: An alternative syntax for reagents that permits whitespace in properties,
//: grouped by brackets. We'll use this ability in the next layer, when we
//: generalize types from lists to trees of properties.

:(scenarios load)
:(scenario dilated_reagent)
def main [
  {1: number, foo: bar} <- copy 34
]
+parse:   product: {1: "number", "foo": "bar"}

:(scenario load_trailing_space_after_curly_bracket)
def main [
  # line below has a space at the end
  { 
]
# successfully parsed

:(scenario dilated_reagent_with_comment)
def main [
  {1: number, foo: bar} <- copy 34  # test comment
]
+parse:   product: {1: "number", "foo": "bar"}
$error: 0

:(scenario dilated_reagent_with_comment_immediately_following)
def main [
  1:number <- copy {34: literal}  # test comment
]
$error: 0

//: First augment next_word to group balanced brackets together.

:(before "End next_word Special-cases")
if (in.peek() == '(')
  return slurp_balanced_bracket(in);
// treat curlies mostly like parens, but don't mess up labels
if (start_of_dilated_reagent(in))
  return slurp_balanced_bracket(in);

:(code)
// A curly is considered a label if it's the last thing on a line. Dilated
// reagents should remain all on one line.
bool start_of_dilated_reagent(istream& in) {
  if (in.peek() != '{') return false;
  int pos = in.tellg();
  in.get();  // slurp '{'
  skip_whitespace_but_not_newline(in);
  char next = in.peek();
  in.seekg(pos);
  return next != '\n';
}

// Assume the first letter is an open bracket, and read everything until the
// matching close bracket.
// We balance {} () and [].
string slurp_balanced_bracket(istream& in) {
  ostringstream result;
  char c;
  list<char> open_brackets;
  while (in >> c) {
    if (c == '(') open_brackets.push_back(c);
    if (c == ')') {
      if (open_brackets.empty() || open_brackets.back() != '(') {
        raise << "unbalanced ')'\n" << end();
        continue;
      }
      assert(open_brackets.back() == '(');
      open_brackets.pop_back();
    }
    if (c == '[') open_brackets.push_back(c);
    if (c == ']') {
      if (open_brackets.empty() || open_brackets.back() != '[') {
        raise << "unbalanced ']'\n" << end();
        continue;
      }
      open_brackets.pop_back();
    }
    if (c == '{') open_brackets.push_back(c);
    if (c == '}') {
      if (open_brackets.empty() || open_brackets.back() != '{') {
        raise << "unbalanced '}'\n" << end();
        continue;
      }
      open_brackets.pop_back();
    }
    result << c;
    if (open_brackets.empty()) break;
  }
  skip_whitespace_and_comments_but_not_newline(in);
  return result.str();
}

:(after "Parsing reagent(string s)")
if (starts_with(s, "{")) {
  assert(properties.empty());
  istringstream in(s);
  in >> std::noskipws;
  in.get();  // skip '{'
  name = slurp_key(in);
  if (name.empty()) {
    raise << "invalid reagent '" << s << "' without a name\n" << end();
    return;
  }
  if (name == "}") {
    raise << "invalid empty reagent '" << s << "'\n" << end();
    return;
  }
  {
    string s = next_word(in);
    if (s.empty()) {
      assert(!has_data(in));
      raise << "incomplete dilated reagent at end of file (0)\n" << end();
      return;
    }
    string_tree* type_names = new string_tree(s);
    // End Parsing Dilated Reagent Type Property(type_names)
    type = new_type_tree(type_names);
    delete type_names;
  }
  while (has_data(in)) {
    string key = slurp_key(in);
    if (key.empty()) continue;
    if (key == "}") continue;
    string s = next_word(in);
    if (s.empty()) {
      assert(!has_data(in));
      raise << "incomplete dilated reagent at end of file (1)\n" << end();
      return;
    }
    string_tree* value = new string_tree(s);
    // End Parsing Dilated Reagent Property(value)
    properties.push_back(pair<string, string_tree*>(key, value));
  }
  return;
}

:(code)
string slurp_key(istream& in) {
  string result = next_word(in);
  if (result.empty()) {
    assert(!has_data(in));
    raise << "incomplete dilated reagent at end of file (2)\n" << end();
    return result;
  }
  while (!result.empty() && *result.rbegin() == ':')
    strip_last(result);
  while (isspace(in.peek()) || in.peek() == ':')
    in.get();
  return result;
}
^
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# Some primitives for checking the state of fake screen objects.

# validate data on screen regardless of attributes (color, bold, etc.)
# Mu doesn't have multi-line strings, so we provide functions for rows or portions of rows.
# Tab characters (that translate into multiple screen cells) not supported.

fn check-screen-row screen: (addr screen), y: int, expected: (addr array byte), msg: (addr array byte) {
  check-screen-row-from screen, 0/x, y, expected, msg
}

fn check-screen-row-from _screen: (addr screen), x: int, y: int, expected: (addr array byte), msg: (addr array byte) {
  var screen/esi: (addr screen) <- copy _screen
  var failure-count/edi: int <- copy 0
  var index/ecx: int <- screen-cell-index screen, x, y
  # compare 'expected' with the screen contents starting at 'index', grapheme by grapheme
  var e: (stream byte 0x100)
  var e-addr/edx: (addr stream byte) <- address e
  write e-addr, expected
  {
    var done?/eax: boolean <- stream-empty? e-addr
    compare done?, 0
    break-if-!=
    var _g/eax: grapheme <- screen-grapheme-at-index screen, index
    var g/ebx: grapheme <- copy _g
    var expected-grapheme/eax: grapheme <- read-grapheme e-addr
    # compare graphemes
    $check-screen-row-from:compare-graphemes: {
      # if expected-grapheme is space, null grapheme is also ok
      {
        compare expected-grapheme, 0x20
        break-if-!=
        compare g, 0
        break-if-= $check-screen-row-from:compare-graphemes
      }
      # if (g == expected-grapheme) print "."
      compare g, expected-grapheme
      break-if-=
      # otherwise print an error
      failure-count <- increment
      draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, msg, 3/fg/cyan, 0/bg
      draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ": expected '", 3/fg/cyan, 0/bg
      draw-grapheme-at-cursor 0/screen, expected-grapheme, 3/cyan, 0/bg
      move-cursor-rightward-and-downward 0/screen, 0/xmin, 0x80/xmax=screen-width
      draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, "' at (", 3/fg/cyan, 0/bg
      draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, x, 3/fg/cyan, 0/bg
      draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ", ", 3/fg/cyan, 0/bg
      draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, y, 3/fg/cyan, 0/bg
      draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ") but observed '", 3/fg/cyan, 0/bg
      draw-grapheme-at-cursor 0/screen, g, 3/cyan, 0/bg
      move-cursor-rightward-and-downward 0/screen, 0/xmin, 0x80/xmax=screen-width
      draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, "'", 3/fg/cyan, 0/bg
      move-cursor-to-left-margin-of-next-line 0/screen
    }
    index <- increment
    increment x
    loop
  }
  # if any assertions failed, count the test as failed
  compare failure-count, 0
  {
    break-if-=
    count-test-failure
    return
  }
  # otherwise print a "."
  draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ".", 3/fg/cyan, 0/bg
}

# various variants by screen-cell attribute; spaces in the 'expected' data should not match the attribute

fn check-screen-row-in-color screen: (addr screen), fg: int, y: int, expected: (addr array byte), msg: (addr array byte) {
  check-screen-row-in-color-from screen, fg, y, 0/x, expected, msg
}

fn check-screen-row-in-color-from _screen: (addr screen), fg: int, y: int, x: int, expected: (addr array byte), msg: (addr array byte) {
  var screen/esi: (addr screen) <- copy _screen
  var index/ecx: int <- screen-cell-index screen, x, y
  # compare 'expected' with the screen contents starting at 'index', grapheme by grapheme
  var e: (stream byte 0x100)
  var e-addr/edx: (addr stream byte) <- address e
  write e-addr, expected
  {
    var done?/eax: boolean <- stream-empty? e-addr
    compare done?, 0
    break-if-!=
    var _g/eax: grapheme <- screen-grapheme-at-index screen, index
    var g/ebx: grapheme <- copy _g
    var _expected-grapheme/eax: grapheme <- read-grapheme e-addr
    var expected-grapheme/edi: grapheme <- copy _expected-grapheme
    $check-screen-row-in-color-from:compare-cells: {
      # if expected-grapheme is space, null grapheme is also ok
      {
        compare expected-grapheme, 0x20
        break-if-!=
        compare g, 0
        break-if-= $check-screen-row-in-color-from:compare-cells
      }
      # if expected-grapheme is space, a different color is ok
      {
        compare expected-grapheme, 0x20
        break-if-!=
        var color/eax: int <- screen-color-at-index screen, index
        compare color, fg
        break-if-!= $check-screen-row-in-color-from:compare-cells
      }
      # compare graphemes
      $check-screen-row-in-color-from:compare-graphemes: {
        # if (g == expected-grapheme) print "."
        compare g, expected-grapheme
        {
          break-if-!=
          draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ".", 3/fg/cyan, 0/bg
          break $check-screen-row-in-color-from:compare-graphemes
        }
        # otherwise print an error
        count-test-failure
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, msg, 3/fg/cyan, 0/bg
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ": expected '", 3/fg/cyan, 0/bg
        draw-grapheme-at-cursor 0/screen, expected-grapheme, 3/cyan, 0/bg
        move-cursor-rightward-and-downward 0/screen, 0/xmin, 0x80/xmax=screen-width
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, "' at (", 3/fg/cyan, 0/bg
        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, x, 3/fg/cyan, 0/bg
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ", ", 3/fg/cyan, 0/bg
        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, y, 3/fg/cyan, 0/bg
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ") but observed '", 3/fg/cyan, 0/bg
        draw-grapheme-at-cursor 0/screen, g, 3/cyan, 0/bg
        move-cursor-rightward-and-downward 0/screen, 0/xmin, 0x80/xmax=screen-width
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, "'", 3/fg/cyan, 0/bg
        move-cursor-to-left-margin-of-next-line 0/screen
      }
      $check-screen-row-in-color-from:compare-colors: {
        var color/eax: int <- screen-color-at-index screen, index
        compare fg, color
        {
          break-if-!=
          draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ".", 3/fg/cyan, 0/bg
          break $check-screen-row-in-color-from:compare-colors
        }
        # otherwise print an error
        count-test-failure
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, msg, 3/fg/cyan, 0/bg
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ": expected '", 3/fg/cyan, 0/bg
        draw-grapheme-at-cursor 0/screen, expected-grapheme, 3/cyan, 0/bg
        move-cursor-rightward-and-downward 0/screen, 0/xmin, 0x80/xmax=screen-width
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, "' at (", 3/fg/cyan, 0/bg
        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, x, 3/fg/cyan, 0/bg
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ", ", 3/fg/cyan, 0/bg
        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, y, 3/fg/cyan, 0/bg
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ") in color ", 3/fg/cyan, 0/bg
        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, fg, 3/fg/cyan, 0/bg
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, " but observed color ", 3/fg/cyan, 0/bg
        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, color, 3/fg/cyan, 0/bg
        move-cursor-to-left-margin-of-next-line 0/screen
      }
    }
    index <- increment
    increment x
    loop
  }
}

fn check-screen-row-in-background-color screen: (addr screen), bg: int, y: int, expected: (addr array byte), msg: (addr array byte) {
  check-screen-row-in-background-color-from screen, bg, y, 0/x, expected, msg
}

fn check-screen-row-in-background-color-from _screen: (addr screen), bg: int, y: int, x: int, expected: (addr array byte), msg: (addr array byte) {
  var screen/esi: (addr screen) <- copy _screen
  var index/ecx: int <- screen-cell-index screen, x, y
  # compare 'expected' with the screen contents starting at 'index', grapheme by grapheme
  var e: (stream byte 0x100)
  var e-addr/edx: (addr stream byte) <- address e
  write e-addr, expected
  {
    var done?/eax: boolean <- stream-empty? e-addr
    compare done?, 0
    break-if-!=
    var _g/eax: grapheme <- screen-grapheme-at-index screen, index
    var g/ebx: grapheme <- copy _g
    var _expected-grapheme/eax: grapheme <- read-grapheme e-addr
    var expected-grapheme/edi: grapheme <- copy _expected-grapheme
    $check-screen-row-in-background-color-from:compare-cells: {
      # if expected-grapheme is space, null grapheme is also ok
      {
        compare expected-grapheme, 0x20
        break-if-!=
        compare g, 0
        break-if-= $check-screen-row-in-background-color-from:compare-cells
      }
      # if expected-grapheme is space, a different background-color is ok
      {
        compare expected-grapheme, 0x20
        break-if-!=
        var background-color/eax: int <- screen-background-color-at-index screen, index
        compare background-color, bg
        break-if-!= $check-screen-row-in-background-color-from:compare-cells
      }
      # compare graphemes
      $check-screen-row-in-background-color-from:compare-graphemes: {
        # if (g == expected-grapheme) print "."
        compare g, expected-grapheme
        {
          break-if-!=
          draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ".", 3/fg/cyan, 0/bg
          break $check-screen-row-in-background-color-from:compare-graphemes
        }
        # otherwise print an error
        count-test-failure
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, msg, 3/fg/cyan, 0/bg
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ": expected '", 3/fg/cyan, 0/bg
        draw-grapheme-at-cursor 0/screen, expected-grapheme, 3/cyan, 0/bg
        move-cursor-rightward-and-downward 0/screen, 0/xmin, 0x80/xmax=screen-width
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, "' at (", 3/fg/cyan, 0/bg
        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, x, 3/fg/cyan, 0/bg
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ", ", 3/fg/cyan, 0/bg
        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, y, 3/fg/cyan, 0/bg
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ") but observed '", 3/fg/cyan, 0/bg
        draw-grapheme-at-cursor 0/screen, g, 3/cyan, 0/bg
        move-cursor-rightward-and-downward 0/screen, 0/xmin, 0x80/xmax=screen-width
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, "'", 3/fg/cyan, 0/bg
        move-cursor-to-left-margin-of-next-line 0/screen
        break $check-screen-row-in-background-color-from:compare-graphemes
      }
      $check-screen-row-in-background-color-from:compare-background-colors: {
        var background-color/eax: int <- screen-background-color-at-index screen, index
        compare bg, background-color
        {
          break-if-!=
          draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ".", 3/fg/cyan, 0/bg
          break $check-screen-row-in-background-color-from:compare-background-colors
        }
        # otherwise print an error
        count-test-failure
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, msg, 3/fg/cyan, 0/bg
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ": expected '", 3/fg/cyan, 0/bg
        draw-grapheme-at-cursor 0/screen, expected-grapheme, 3/cyan, 0/bg
        move-cursor-rightward-and-downward 0/screen, 0/xmin, 0x80/xmax=screen-width
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, "' at (", 3/fg/cyan, 0/bg
        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, x, 3/fg/cyan, 0/bg
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ", ", 3/fg/cyan, 0/bg
        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, y, 3/fg/cyan, 0/bg
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ") in background-color ", 3/fg/cyan, 0/bg
        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, bg, 3/fg/cyan, 0/bg
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, " but observed background-color ", 3/fg/cyan, 0/bg
        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, background-color, 3/fg/cyan, 0/bg
        move-cursor-to-left-margin-of-next-line 0/screen
      }
    }
    index <- increment
    increment x
    loop
  }
}

# helpers for checking just background color, not screen contents
# these can validate bg for spaces

fn check-background-color-in-screen-row screen: (addr screen), bg: int, y: int, expected-bitmap: (addr array byte), msg: (addr array byte) {
  check-background-color-in-screen-row-from screen, bg, y, 0/x, expected-bitmap, msg
}

fn check-background-color-in-screen-row-from _screen: (addr screen), bg: int, y: int, x: int, expected-bitmap: (addr array byte), msg: (addr array byte) {
  var screen/esi: (addr screen) <- copy _screen
  var failure-count: int
  var index/ecx: int <- screen-cell-index screen, x, y
  # compare background color where 'expected-bitmap' is a non-space
  var e: (stream byte 0x100)
  var e-addr/edx: (addr stream byte) <- address e
  write e-addr, expected-bitmap
  {
    var done?/eax: boolean <- stream-empty? e-addr
    compare done?, 0
    break-if-!=
    var _expected-bit/eax: grapheme <- read-grapheme e-addr
    var expected-bit/edi: grapheme <- copy _expected-bit
    $check-background-color-in-screen-row-from:compare-cells: {
      var background-color/eax: int <- screen-background-color-at-index screen, index
      # if expected-bit is space, assert that background is NOT bg
      compare expected-bit, 0x20
      {
        break-if-!=
        compare background-color, bg
        break-if-!= $check-background-color-in-screen-row-from:compare-cells
        increment failure-count
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, msg, 3/fg/cyan, 0/bg
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ": expected (", 3/fg/cyan, 0/bg
        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, x, 3/fg/cyan, 0/bg
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ", ", 3/fg/cyan, 0/bg
        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, y, 3/fg/cyan, 0/bg
        draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ") to not be in background-color ", 3/fg/cyan, 0/bg
        draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, bg, 3/fg/cyan, 0/bg
        move-cursor-to-left-margin-of-next-line 0/screen
        break $check-background-color-in-screen-row-from:compare-cells
      }
      # otherwise assert that background IS bg
      compare background-color, bg
      break-if-= $check-background-color-in-screen-row-from:compare-cells
      increment failure-count
      draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, msg, 3/fg/cyan, 0/bg
      draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ": expected (", 3/fg/cyan, 0/bg
      draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, x, 3/fg/cyan, 0/bg
      draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ", ", 3/fg/cyan, 0/bg
      draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, y, 3/fg/cyan, 0/bg
      draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ") in background-color ", 3/fg/cyan, 0/bg
      draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, bg, 3/fg/cyan, 0/bg
      draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, " but observed background-color ", 3/fg/cyan, 0/bg
      draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, background-color, 3/fg/cyan, 0/bg
      move-cursor-to-left-margin-of-next-line 0/screen
    }
    index <- increment
    increment x
    loop
  }
  # if any assertions failed, count the test as failed
  compare failure-count, 0
  {
    break-if-=
    count-test-failure
    return
  }
  # otherwise print a "."
  draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, ".", 3/fg/cyan, 0/bg
}

fn test-draw-single-grapheme {
  var _screen: screen
  var screen/esi: (addr screen) <- address _screen
  initialize-screen screen, 5, 4, 0/no-pixel-graphics
  draw-code-point screen, 0x61/a, 0/x, 0/y, 1/fg, 2/bg
  check-screen-row screen, 0/y, "a", "F - test-draw-single-grapheme"  # top-left corner of the screen
  check-screen-row-in-color screen, 1/fg, 0/y, "a", "F - test-draw-single-grapheme-fg"
  check-screen-row-in-background-color screen, 2/bg, 0/y, "a", "F - test-draw-single-grapheme-bg"
  check-background-color-in-screen-row screen, 2/bg, 0/y, "x ", "F - test-draw-single-grapheme-bg2"
}

fn test-draw-multiple-graphemes {
  var _screen: screen
  var screen/esi: (addr screen) <- address _screen
  initialize-screen screen, 0x10/rows, 4/cols, 0/no-pixel-graphics
  draw-text-wrapping-right-then-down-from-cursor-over-full-screen screen, "Hello, 世界", 1/fg, 2/bg
  check-screen-row screen, 0/y, "Hello, 世界", "F - test-draw-multiple-graphemes"
  check-screen-row-in-color screen, 1/fg, 0/y, "Hello, 世界", "F - test-draw-multiple-graphemes-fg"
  check-background-color-in-screen-row screen, 2/bg, 0/y, "xxxxxxxxx ", "F - test-draw-multiple-graphemes-bg2"
}