Add metadata property to parameters

Author: arnaud-morvan

python/plugins/processing/core/parameters.py

@@ -58,7 +58,10 @@ class Parameter(object):
     take as input.
     """
 
-    def __init__(self, name='', description='', default=None, optional=False):
+    default_metadata = {}
+
+    def __init__(self, name='', description='', default=None, optional=False,
+                 metadata={}):
         self.name = name
         self.description = description
         self.default = default
@@ -73,6 +76,10 @@ def __init__(self, name='', description='', default=None, optional=False):
 
         self.optional = parseBool(optional)
 
+        # TODO: make deep copy and deep update
+        self.metadata = self.default_metadata.copy()
+        self.metadata.update(metadata)
+
     def setValue(self, obj):
         """
         Sets the value of the parameter.