The page_commenter function displays the original text and any comments that have been added. Which of the following is TRUE about how the page_commenter function works?

Select one answer, then check.

• The content variable holds a list of the PageContent, which are all Div objects.
  Not quite. content starts as [Header("Code Commenter")], so its first element is a Header, not a Div.
• Each iteration of the for loop adds up to three new elements per iteration, since there are three append calls.
  Not quite. The first two append calls are in an if/else, so only one of them ever runs; combined with the separate if line.comment append, at most two elements are added per iteration, never three.
• If a line does not have any text, then no text is shown but the button to add a new comment still appears.
  Not quite. The else branch for an empty line appends Div(classes="comment-line", style_height="1.5em"), a blank spacer with no button at all.
• The Div components added in the loop have either zero, one, or two components inside of them (depending on whether the line has text and there are comments).
  Correct. A blank line's spacer Div has zero content components, a comment's Div(small_font(line.comment), ...) has one, and a line with text has two: Div(line.original, Button(...), ...).

Which of these is NOT an accurate description of how functions are decomposed in this program?

Select one answer, then check.

• The start_commenting route calls the error_page function.
  Accurate. start_commenting returns error_page(...) when there's no file and no text.
• The start_commenting route calls the page_commenter function.
  Accurate. Once the lines are parsed, it returns page_commenter(state).
• The start_commenting route calls the parse_lines function.
  Accurate. lines = parse_lines(text) is right there in the function body.
• The save_comment route calls the page_commenter function.
  Accurate. save_comment ends with return page_commenter(state).
• The save_comment route calls the parse_lines function.
  Correct, this is the false one. save_comment only does state.comments[index].comment = comment_box before calling page_commenter; it never calls parse_lines, which only runs once, from start_commenting.

The start_commenting function updates the State to include the original_text field, which contains the original text to be commented on. Why is the original_text field kept in the State?

Select one answer, then check.

• The page_commenter function needs it to display the original text.
  Not quite. page_commenter never reads state.original_text; it builds its display from state.comments, where each Line already carries its own original text.
• The page_commenter function needs it to display the comments.
  Not quite, for the same reason: comments come from each Line.comment, not from state.original_text.
• The add_comment function needs it to add new comments.
  Not quite. There is no add_comment function in this program; comments are saved by save_comment, which doesn't use original_text either.
• The add_comment function needs it to display the comments.
  Not quite, for the same reason: there is no add_comment function here.
• The index function needs it to display the original text if the user resets.
  Correct. index pre-fills the text area with TextArea("text_box", state.original_text), so when the "Reset" button on the commenting page sends the user back to index, their earlier text reappears instead of an empty box.
• The index function needs it to display the text immediately after the user uploads a file.
  Not quite. Uploading a file and pressing "Start" goes straight to page_commenter, not back to index, so index is never shown "immediately after" an upload.