!7

cmodule TextAssist > DynPrintLogAndEnabled {
  int moduleID = 576; // editor ID, XXX
  S lastText;
  
  start {
    doEvery(1.0, r check);
  }
  
  void check {
    S text = cast dm_rcall getText(moduleID);
    pcall {
      compareTexts(lastText, text);
    }
    setField(lastText := text);
  }

  void compareTexts(S lastText, S text) {
    LS linesA = lines(lastText);
    LS linesB = lines(text);

    // need same number of lines
    if (l(linesA) != l(linesB)) ret with print("Line count changed, exiting");

    L<Int> indices = differingIndices(linesA, linesB);
    if (l(indices) != 1) ret with print("# changed lines: " + l(indices) + ", exiting");

    int i = first(indices);
    S oldLine = linesA.get(i), newLine = linesB.get(i);

    // Make a TextEdit to see what is changed in line
    TextEdit edit = createTextEdit(oldLine, newLine);
    if (edit == null) ret with print("Line not changed? Weird.");

    print("Have text edit in line " + i + ": " + edit);
  }
}