--- a/pvl/dhcp/config.py	Wed Feb 25 15:55:23 2015 +0200
+++ b/pvl/dhcp/config.py	Thu Feb 26 14:31:16 2015 +0200
@@ -219,3 +219,83 @@
         assert not self.block
 
         return self.items, self.blocks
+
+def build_field (value):
+    """
+        Build a single field as part of a dhcp.conf line.
+
+        >>> print build_field('foo')
+        foo
+        >>> print build_field('foo bar')
+        "foo bar"
+    """
+
+    value = str(value)
+
+    if any(c.isspace() for c in value):
+        # quoted
+        return '"{value}"'.format(value=value)
+    else:
+        return value
+
+def build_line (item, end, indent=0):
+    """
+        Build a structured line.
+
+        >>> print build_line(['foo'], ';')
+        foo;
+        >>> print build_line(['host', 'foo'], ' {')
+        host foo {
+        >>> print build_line(['foo', 'bar quux'], ';', indent=1)
+            foo "bar quux";
+    """
+
+    return '    '*indent + ' '.join(build_field(field) for field in item) + end
+
+def build_item (item, **opts):
+    """
+        Build a single parameter line.
+
+        >>> print build_item(['foo'])
+        foo;
+    """
+
+    return build_line(item, end=';', **opts)
+
+def build_block (block, items, blocks=(), indent=0, comment=None):
+    """
+        Build a complete block.
+
+        >>> for line in build_block(('host', 'foo'), [('hardware', 'ethernet', '00:11:22:33:44:55')], comment="Testing"): print line
+        # Testing
+        host foo {
+            hardware ethernet 00:11:22:33:44:55;
+        }
+        >>> for line in build_block(('group', ), [('next-server', 'booter')], [ \
+                    (('host', 'foo'), [('hardware', 'ethernet', '00:11:22:33:44:55')], ()) \
+                ]): print line
+        group {
+            next-server booter;
+        <BLANKLINE>
+            host foo {
+                hardware ethernet 00:11:22:33:44:55;
+            }
+        }
+    """
+
+    if comment:
+        yield build_line((), end="# {comment}".format(comment=comment), indent=indent)
+
+    yield build_line(block, end=' {', indent=indent)
+    
+    for item in items:
+        yield build_item(item, indent=indent+1)
+
+    for subblock, subitems, subblocks in blocks:
+        yield ''
+
+        for line in build_block(subblock, subitems, subblocks, indent=indent+1):
+            yield line
+
+    yield build_line((), end='}', indent=indent)
+