lib/ordered_tree: improve doc and docunits

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/lib/ordered_tree.nit b/lib/ordered_tree.nit
index d64df28..5c42f46 100644 (file)
--- a/lib/ordered_tree.nit
+++ b/lib/ordered_tree.nit
@@ -21,24 +21,57 @@ module ordered_tree
 #
 # Ordered tree are tree where the elements of a same parent are in a specific order
 #
-# The class can be used as it to work with generic tree.
-# The class can also be specialized to provide more specific behavior.
+# Elements of the trees are added with the `add` method that takes a parent and
+# a sub-element.
+# If the parent is `null`, then the element is considered a root.
+#
+# ~~~~
+# var t = new OrderedTree[String]
+# t.add(null, "root")
+# t.add("root", "child1")
+# t.add("root", "child2")
+# t.add("child1", "grand-child")
+# assert t.length == 4
+# ~~~~
+#
+# By default, the elements with a same parent
+# are visited in the order they are added.
+#
+# ~~~
+# assert t.to_a == ["root", "child1", "grand-child", "child2"]
+# assert t.write_to_string == """
+# root
+# |--child1
+# |  `--grand-child
+# `--child2
+# """
+# ~~~
+#
+# The `sort_with` method can be used reorder elements
+#
+# ~~~
+# t.add("root", "aaa")
+# assert t.to_a == ["root", "child1", "grand-child", "child2", "aaa"]
+# t.sort_with(alpha_comparator)
+# assert t.to_a == ["root", "aaa", "child1", "grand-child", "child2"]
+# ~~~
+#
+# This class can be used as it to work with generic trees but can also be specialized to provide more specific
+# behavior or display. It is why the internal attributes are mutable.
 class OrderedTree[E: Object]
        super Streamable
        super Collection[E]
 
-       # Sequence
+       # The roots of the tree (in sequence)
        var roots = new Array[E]
+
+       # The branches of the trees.
+       # For each element, the ordered array of its direct sub-elements.
        var sub = new HashMap[E, Array[E]]
 
-       # Add a new element `e` in the tree
+       # Add a new element `e` in the tree.
        # `p` is the parent of `e`.
        # if `p` is null, then `e` is a root element.
-       #
-       # By defauld, the elements with a same parent 
-       # are displayed in the order they are added.
-       #
-       # The `sort_with` method can be used reorder elements
        fun add(p: nullable E, e: E)
        do
                if p == null then