add linked lists

README.md

@@ -37,3 +37,13 @@ You can look at a list of tuples as a list of list too:
 Here's how to describe a hashtable with 3 elements in 2 different buckets:
 
 <img src=images/hashtable.png width=350>
+
+If you want the graphviz/dot source, use `source` field of returned `graphviz.files.Source` object.
+
+For 1.1, I added linked lists. Figuring out that layout was annoying. You're welcome. ;)
+
+<img src="images/llist.png" width=500>
+
+Here's an example of specifying lambda functions to extract values from nodes:
+
+<img src="images/tuplellist.png" width=450>

lolviz.py

@@ -23,6 +23,7 @@ def dictviz(d):
     return graphviz.Source(s)
 
 
+
 def listviz(elems, showassoc=True):
     """
     Display a list of elements in a horizontal fashion.
@@ -49,6 +50,48 @@ def listviz(elems, showassoc=True):
     return graphviz.Source(s)
 
 
+def llistviz(head,
+             valuefield='value', nextfield='next',
+             value=None, next=None): # lambda/functions to obtain value/next fields
+    """
+    Display a linked list in a horizontal fashion. The fields/attributes
+    obtained via getattr() are assumed to be 'value' and 'next' but you
+    can passing different names, if you like.  You can also pass in
+    lambdas or functions that indicate how to get the node's value or next
+    fields. The default is to define value to get field valuefield,
+    similar for next.
+    """
+    if value is None:
+        value = lambda p : getattr(p,valuefield)
+    if next is None:
+        next = lambda p : getattr(p,nextfield)
+    s = """
+    digraph G {
+        nodesep=.05;
+        rankdir=LR;
+        ranksep=.2;
+        node [shape=box, penwidth="0.5",width=.1,height=.1];
+    """
+    p = head
+    i = 0
+    edges = []
+    while p is not None:
+        html = llist_nodeviz(value(p), valuefield, nextfield)
+        if next(p) is not None:
+            edges.append( (i,i+1) )
+        p = next(p)
+        s += '    node%d [space="0.0", margin="0.01", fontcolor="#444443", fontname="Helvetica", label=<%s>];\n' % (i,html)
+        i += 1
+
+    # draw edges
+    for e in edges:
+        s += 'node%d:next:c -> node%d:value [dir=both, tailclip=false, arrowtail=dot, penwidth="0.5", color="#444443", arrowsize=.4]\n' % e
+
+    s += "}\n"
+    # print s
+    return graphviz.Source(s)
+
+
 def lolviz(table, showassoc=True):
     """
     Given a list of lists such as:
@@ -111,7 +154,9 @@ def islol(table):
 
 
 def elviz(el, showassoc):
-    if showassoc and type(el) == tuple and len(el) == 2:
+    if el is None:
+        els = ' '
+    elif showassoc and type(el) == tuple and len(el) == 2:
         els = "%s&rarr;%s" % (elviz(el[0], showassoc), elviz(el[1], showassoc))
     elif type(el)==set:
         els = '{'+', '.join([elviz(e, showassoc) for e in el])+'}'
@@ -124,15 +169,61 @@ def elviz(el, showassoc):
     return els
 
 
-def idx_elviz(idx, el, showassoc):
+def label_elviz(label, el, showassoc, port=None):
+    if port is None:
+        port = label
+    return \
+        """
+        <table BORDER="0" CELLBORDER="1" CELLSPACING="0">
+          <tr>
+            <td cellspacing="0" bgcolor="#FBFEB0" border="1" sides="b" valign="top"><font color="#444443" point-size="9">%s</font></td>
+          </tr>
+          <tr>
+            <td port="%s" bgcolor="#FBFEB0" border="0" align="center"><font point-size="11">%s</font></td>
+          </tr>
+        </table>
+        """ % (label, port, elviz(el,showassoc))
+
+
+def llist_nodeviz(nodevalue, value, next):
     return \
         """
         <table BORDER="0" CELLBORDER="1" CELLSPACING="0">
           <tr>
-            <td cellspacing="0" bgcolor="#FBFEB0" border="1" sides="b" valign="top"><font color="#444443" point-size="9">%d</font></td>
+            <td cellspacing="0" bgcolor="#FBFEB0" border="1" sides="br" valign="top"><font color="#444443" point-size="9">%s</font></td>
+            <td cellspacing="0" bgcolor="#FBFEB0" border="1" sides="b" valign="top"><font color="#444443" point-size="9">%s</font></td>
           </tr>
           <tr>
-            <td bgcolor="#FBFEB0" border="0" align="center"><font point-size="11">%s</font></td>
+            <td port="value" bgcolor="#FBFEB0" border="1" sides="r" align="center"><font point-size="11">%s</font></td>
+            <td port="next" bgcolor="#FBFEB0" border="0" align="center"><font point-size="11">%s</font></td>
           </tr>
         </table>
-        """ % (idx, elviz(el,showassoc))
+        """ % (value,next, elviz(nodevalue,True), ' ')
+
+
+def idx_elviz(idx, el, showassoc):
+    return label_elviz(str(idx), el, showassoc)
+
+
+if __name__ == '__main__':
+    # test linked list node
+    class Node:
+        def __str__(self):
+            return "(%s,%s)" % (self.value, str(self.next))
+
+        def __repr__(self):
+            return str(self)
+
+        def __init__(self, value, next=None):
+            self.value = value
+            self.next = next
+
+    head = Node('tombu')
+    head = Node('parrt', head)
+    head = Node({3,4}, head)
+    g = llistviz(head)
+    # or
+    g = llistviz(head, valuefield='value', nextfield='next')
+    # or
+    g = llistviz(head, value=lambda p:p.value, next=lambda p:p.next)
+    g.render(view=True)

setup.py

@@ -2,7 +2,7 @@
 
 setup(
     name='lolviz',
-    version='1.0.2',
+    version='1.1',
     url='https://github.com/parrt/lolviz',
     license='BSD',
     py_modules=['lolviz'],