diff -r a2f0cb2b5c13 -r 0dd7f2c9fd81 src/row.rs
--- a/src/row.rs	Tue Jan 31 23:25:50 2023 +0100
+++ b/src/row.rs	Sat Feb 04 22:46:13 2023 +0100
@@ -1,24 +1,37 @@
-/*** Row ****/
-// a row of cards on the table (max 5)
+/// Implementation of a Row of Cards on the Table (max 5)
 
+// We use std::mem::take to do tricks with vector members and ownership.
 use std::{collections::VecDeque, mem};
 
 use crate::card::Card;
 
 #[derive(Debug)]
+/// A `Row` of [`Card`]s, in a two-ended vector (`VecDeque`).
+/// A Row is smart and can do a few things on herself.
 pub(crate) struct Row {
     cards: VecDeque<Card>,
 }
 
 impl Row {
+    /// The maximum length of a Row. More cards cause overflow and force collection.
     const MAX_LEN: usize = 5;
 
+    /// Create a new [`Row`] with capacity of 5 [`Card`]s.
     pub(crate) fn new() -> Self {
         Row {
             cards: VecDeque::with_capacity(5),
         }
     }
 
+    /// Push a [`Card`] to the end of the Row.
+    /// If it would make Row over maximum length the function 
+    /// returns the content of the row, and then push the new
+    /// Card as the new Row head.
+    /// Otherwise return None.
+    /// # Arguments
+    /// - [`Card`] - the new card to put into the Row
+    /// # Returns
+    /// - `Option<VecDequeue<Card>>` - None or Some(cards) to be collected from Row
     pub(crate) fn push_or_collect( &mut self, card: Card ) -> Option<VecDeque<Card>> {
         trace!("Called push_or_collect on row {:?}", &self);
         if self.cards.len() < Self::MAX_LEN {
@@ -28,21 +41,28 @@
 
         } else {
             trace!("Row is full, len {}, maxlen {}", self.cards.len(), Self::MAX_LEN);
-            // row overflow
+            // Row overflow. We take out `cards` from `self` with its ownership and 
+            // leave the default (empty VecDeque) in its place, without disturbing
+            // `self` ownership.
             let row_cards = mem::take( &mut self.cards );
+            // We put new card as new Row head.
             self.cards.push_back(card);
             if self.cards.len() != 1 {
                 panic!("New row must have one card, not {}", self.cards.len());
             }
+            // Return the collected old Row content
             Some(row_cards)
         }
     }
 
+    /// Take out all `cards` (and their ownership) and return them.
     pub(crate) fn take_row( &mut self ) -> VecDeque<Card> {
         // take cards and empty the row
         mem::take( &mut self.cards )
     }
 
+    /// Return the `value` of the last card in the Row.
+    /// This is the largest value since the Row is always ordered.
     pub(crate) fn last_card_value(&self) -> i8 {
         // println!("last_card_value: cards {:?}, len {}", self.cards, self.cards.len());
         self.cards.get( self.cards.len()-1 ).unwrap().value
@@ -57,6 +77,10 @@
         sum
     }
 
+    #[allow(dead_code)]
+    /// We could use this, but... borrow checker, you know. Needs more love.
+    /// I could have used `_len` to shut up the dead_code warning, so this is
+    /// another example to do it the other way.
     pub fn len(&self) -> usize {
         self.cards.len()
     }