Add a loadXML function to load an sofa scene from xml in python. (#123)

* Add a loadXML function to load an sofa scene from xml in python with an example.

python3/src/splib3/loaders/__init__.py

@@ -13,9 +13,8 @@
 .. autofunction:: getLoadingLocation
 
 """
-__all__=[]
+__all__=["xmlloader"]
 
-import os
 def getLoadingLocation(filename , source=None):
     """Compute a loading path for the provided filename relative to a given 
        source location
@@ -28,6 +27,8 @@ def getLoadingLocation(filename , source=None):
         The latter is really usefull to make get the path for a file relative
         to the 'current' python source.                    
     """
+    import os
+
     if source == None:
         return filename
 

python3/src/splib3/loaders/xmlloader.py

@@ -0,0 +1,55 @@
+import Sofa
+import SofaRuntime
+import xml.etree.ElementTree as ET
+
+def _processNode(xmlNode, sofaNode, context={}):
+        # set the value of the data field of the sofaNode from the attributes of the xmlNode
+        for name, value in xmlNode.attrib.items():
+            if name in sofaNode.__data__:
+                sofaNode.findData(name).read(value)
+
+        # for each child of the xmlNode
+        for child in xmlNode:
+            # if it is a special one "include"
+            if child.tag == "include":
+                # load the corresponding file
+                filename = SofaRuntime.DataRepository.getFile(child.attrib["href"])
+                n = sofaNode.addChild("Unnamed")
+
+                # create a specific context
+                local_context = context.copy()
+                for name, value in child.attrib.items():
+                    if name not in ["name", "href"]:
+                        local_context[name] = value
+
+                # recursively load the file
+                loadXML(filename, n, local_context)
+            # if it is a node then load and recursively process it
+            elif child.tag == "Node":
+                sofaChild = sofaNode.addChild(child.attrib["name"])
+                _processNode(child, sofaChild, context)
+
+            # otherwise, it is treated as an object
+            else:
+                # override the child attributes from the value from the context
+                for name, value in context.items():
+                    if name in child.attrib:
+                        child.attrib[name] = value
+                sofaNode.addObject(child.tag, **(child.attrib))
+
+def loadXML(filename, sofaNode, context={}):
+    """Load a sofa scene from an xml file and adds it to the provided sofaNode
+
+       Example of use:
+          from splib3.loaders.xmlloader import loadXML
+
+          def createScene(root):
+              loadXML("Caduceus.xml", root)
+    """
+    tree = ET.parse(filename)
+    xmlNode = tree.getroot()
+    _processNode(xmlNode, sofaNode, context)
+    return sofaNode
+
+def createScene(root):
+    loadXML(SofaRuntime.DataRepository.getFile("Demos/caduceus.scn"), root)