Material: Material handling enhancements

Rework of the material handling system.

This first part concntrates on a rework of the material cards.
Rather than use a fixed list of possible properties, properties can
be defined separately in their own files and mixed to provide a
complete list of possible properties. Properties can be inherited.

The cards then provide values for the properties. These can also
be inherited allowing for small changes in cards as required.

The new property definitions are more extensive than previously.
2 and 3 dimensional arrays of properties can be defined. Values
are obtained by calling an API instead of reading from a dictionary.

For compatibility, a Python dictionary of values can be obtained
similar to how it was done previously, but this is considered a
deprecated API and won't support the newer advanced features.

The editor is completely reworked. It will be able to edit older format
material cards, but can only save them in the new format.

For testing during the development phase, a system preference can
specifiy wether the old or new material editors are to be used. This
option will be removed before release.

src/Mod/Material/materialtools/MaterialModels.py

@@ -0,0 +1,163 @@
+# ***************************************************************************
+# *   Copyright (c) 2023 David Carter <dcarter@dvidcarter.ca>               *
+# *                                                                         *
+# *   This program is free software; you can redistribute it and/or modify  *
+# *   it under the terms of the GNU Lesser General Public License (LGPL)    *
+# *   as published by the Free Software Foundation; either version 2 of     *
+# *   the License, or (at your option) any later version.                   *
+# *   for detail see the LICENCE text file.                                 *
+# *                                                                         *
+# *   This program is distributed in the hope that it will be useful,       *
+# *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+# *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+# *   GNU Library General Public License for more details.                  *
+# *                                                                         *
+# *   You should have received a copy of the GNU Library General Public     *
+# *   License along with this program; if not, write to the Free Software   *
+# *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  *
+# *   USA                                                                   *
+# *                                                                         *
+# ***************************************************************************
+
+__title__ = "material model utilities"
+__author__ = "David Carter"
+__url__ = "http://www.freecad.org"
+
+import os
+import io
+from pathlib import Path
+import yaml
+
+import FreeCAD
+
+
+unicode = str
+
+__models = {}
+__modelsByPath = {}
+
+def _dereference(parent, child):
+    # Add the child parameters to the parent
+    parentModel = parent["model"]
+    parentBase = parent["base"]
+    childModel = child["model"]
+    childBase = child["base"]
+    for name, value in childModel[childBase].items():
+        if name not in ["Name", "UUID", "URL", "Description", "DOI", "Inherits"] and \
+            name not in parentModel[parentBase]: # Don't add if it's already there
+            parentModel[parentBase][name] = value
+
+    print("dereferenced:")
+    print(parentModel)
+
+def _dereferenceInheritance(data):
+    if not data["dereferenced"]:
+        data["dereferenced"] = True # Prevent recursion loops
+
+        model = data["model"]
+        base = data["base"]
+        if "Inherits" in model[base]:
+            print("Model '{0}' inherits from:".format(data["name"]))
+            for parent in model[base]["Inherits"]:
+                print("\t'{0}'".format(parent))
+                print("\t\t'{0}'".format(parent.keys()))
+                print("\t\t'{0}'".format(parent["UUID"]))
+
+                # This requires that all models have already been loaded undereferenced
+                child = __models[parent["UUID"]]
+                if child is not None:
+                    _dereference(data, child)
+
+def _dereferenceAll():
+    for data in __models.values():
+        _dereferenceInheritance(data)
+
+def _scanFolder(folder):
+    print("Scanning folder '{0}'".format(folder.absolute()))
+    for child in folder.iterdir():
+        if child.is_dir():
+            _scanFolder(child)
+        else:
+            if child.suffix.lower() == ".yml":
+                data = getModelFromPath(child)
+
+                if data is not None:
+                    __models[data["uuid"]] = data
+                    __modelsByPath[data["path"]] = data
+                    # print(data["model"])
+            else:
+                print("Extension '{0}'".format(child.suffix.lower()))
+
+def _scanModels(libraries):
+    __models = {} # Clear the current library
+    __modelsByPath = {}
+    print("_scanModels")
+    print(libraries)
+    for library in libraries:
+        _scanFolder(Path(library))
+
+    # Satisfy aany inheritances
+    _dereferenceAll()
+
+def getPreferredSaveDirectory():
+    pass
+
+def getModelLibraries():
+
+    libraries = []
+
+    # TODO: Expand beyond the standard models as we do for material paths
+    path = Path(FreeCAD.getResourceDir()) / "Mod/Material/Resources/Models"
+    libraries.append(path)
+
+    _scanModels(libraries)
+
+    return libraries
+
+def getModel(uuid):
+    """
+        Retrieve the specified model.
+    """
+    if len(__models) < 1:
+        getModelLibraries()
+
+    if uuid not in __models:
+        return None
+    return __models[uuid]
+
+def getModelFromPath(filePath):
+    """
+        Retrieve the model at the specified path.
+
+        This may not need public exposure?
+    """
+    try:
+        path = Path(filePath)
+        stream = open(path.absolute(), "r")
+        model = yaml.safe_load(stream)
+
+        base = "Model"
+        if "AppearanceModel" in model:
+            base = "AppearanceModel"
+
+        uuid = model[base]["UUID"]
+        name = model[base]["Name"]
+
+        data = {}
+        data["base"] = base
+        data["name"] = name
+        data["path"] = path.absolute()
+        data["uuid"] = uuid
+        data["model"] = model
+        data["dereferenced"] = False
+        return data
+    except Exception as ex:
+        print("Unable to load '{0}'".format(path.absolute()))
+        print(ex)
+
+    return None
+
+def saveModel(model, path):
+    """
+        Write the model to the specified path
+    """