lib/standard/ropes: Concat nodes cannot be constructed without children anymore.

Signed-off-by: Lucas Bajolet <r4pass@hotmail.com>

diff --git a/lib/standard/ropes.nit b/lib/standard/ropes.nit
index 54e6050..976def9 100644 (file)
--- a/lib/standard/ropes.nit
+++ b/lib/standard/ropes.nit
@@ -51,26 +51,18 @@ private class Concat
        super RopeNode
 
        # Left child of the node
-       var _left: nullable RopeNode = null
+       var left: nullable RopeNode
        # Right child of the node
-       var _right: nullable RopeNode = null
+       var right: nullable RopeNode
 
-       fun left: nullable RopeNode do return _left
-       fun right: nullable RopeNode do return _right
-
-       fun left=(l: RopeNode)
+       init(l: nullable RopeNode, r: nullable RopeNode)
        do
-               _left = l
-               length = l.length
-               if _right != null then length += _right.length
+               left = l
+               right = r
+               if l != null then length += l.length
+               if r != null then length += r.length
        end
 
-       fun right=(r: RopeNode)
-       do
-               _right = r
-               length = r.length
-               if _left != null then length += _left.length
-       end
 end
 
 # Leaf of a Rope, contains a FlatString
@@ -281,36 +273,40 @@ class RopeString
 
                var path = node_at(pos)
 
-               var last_concat = new Concat
+               var last_concat: Concat
 
                if path.offset == 0 then
-                       last_concat.right = path.leaf
-                       if str isa FlatString then last_concat.left = new StringLeaf(str) else last_concat.left = str.as(RopeString).root
+                       if str isa FlatString then
+                               last_concat = new Concat(new StringLeaf(str), path.leaf)
+                       else
+                               last_concat = new Concat(str.as(RopeString).root, path.leaf)
+                       end
                else if path.offset == path.leaf.length then
-                       if str isa FlatString then last_concat.right = new StringLeaf(str) else last_concat.right = str.as(RopeString).root
-                       last_concat.left = path.leaf
+                       if str isa FlatString then
+                               last_concat = new Concat(path.leaf, new StringLeaf(str))
+                       else
+                               last_concat = new Concat(path.leaf, str.as(RopeString).root)
+                       end
                else
                        var s = path.leaf.str
                        var l_half = s.substring(0, s.length - path.offset)
                        var r_half = s.substring_from(s.length - path.offset)
-                       var cct = new Concat
-                       cct.right = new StringLeaf(r_half.as(FlatString))
-                       last_concat.left = new StringLeaf(l_half.as(FlatString))
-                       if str isa FlatString then last_concat.right = new StringLeaf(str) else last_concat.right = str.as(RopeString).root
-                       cct.left = last_concat
-                       last_concat = cct
+                       var cct: Concat
+                       var ll = new StringLeaf(l_half.as(FlatString))
+                       if str isa FlatString then
+                               cct = new Concat(ll, new StringLeaf(str))
+                       else
+                               cct = new Concat(ll, str.as(RopeString).root)
+                       end
+                       last_concat = new Concat(cct, new StringLeaf(r_half.as(FlatString)))
                end
 
                for i in path.stack.reverse_iterator do
-                       var nod = new Concat
                        if i.left then
-                               nod.right = i.node.right.as(not null)
-                               nod.left = last_concat
+                               last_concat = new Concat(last_concat, i.node.right)
                        else
-                               nod.left = i.node.left.as(not null)
-                               nod.right = last_concat
+                               last_concat = new Concat(i.node.left, last_concat)
                        end
-                       last_concat = nod
                end
 
                return new RopeString.from_root(last_concat)
@@ -329,17 +325,25 @@ class RopeString
        # Builds a new path from root to the rightmost node with s appended
        private fun append_to_path(node: RopeNode, s: String): RopeNode
        do
-               var cct = new Concat
+               var cct: Concat
                if node isa Leaf then
-                       cct.left = node
-                       if s isa FlatString then cct.right = new StringLeaf(s) else cct.right = s.as(RopeString).root
-               else if node isa Concat then
-                       var right = node.right
-                       if node.left != null then cct.left = node.left.as(not null)
+                       if s isa FlatString then
+                               cct = new Concat(node, new StringLeaf(s))
+                       else
+                               cct = new Concat(node, s.as(RopeString).root)
+                       end
+               else
+                       var n = node.as(Concat)
+                       var right = n.right
+                       var lft = n.left.as(not null)
                        if right == null then
-                               if s isa FlatString then cct.right = new StringLeaf(s) else cct.right = s.as(RopeString).root
+                               if s isa FlatString then
+                                       cct = new Concat(lft, new StringLeaf(s))
+                               else
+                                       cct = new Concat(lft, s.as(RopeString).root)
+                               end
                        else
-                               cct.right = append_to_path(right, s)
+                               cct = new Concat(lft, append_to_path(right, s))
                        end
                end
                return cct
@@ -375,11 +379,7 @@ class RopeString
 
                for i in path.stack.reverse_iterator do
                        if i.right then continue
-                       var tmp = new Concat
-                       tmp.left = nod
-                       var r = i.node.right
-                       if r != null then tmp.right = r
-                       nod = tmp
+                       nod = new Concat(nod, i.node.right)
                end
 
                var ret = new RopeString
@@ -392,11 +392,7 @@ class RopeString
 
                for i in path.stack.reverse_iterator do
                        if i.left then continue
-                       var tmp = new Concat
-                       tmp.right = nod
-                       var l = i.node.left
-                       if l != null then tmp.left = l
-                       nod = tmp
+                       nod = new Concat(i.node.left, nod)
                end
 
                ret.root = nod