Allow the return of combined IDs for multi-id xpaths.

This is so that an xpath for an SBML local parameter like

/sbml:sbml/sbml:model/sbml:listOfReactions/sbml:reaction[@id='J0']/sbml:kineticLaw/sbml:listOfParameters/sbml:parameter[@id='n']

can return

J0.n or J0_n

instead of just 'n'.

Backwards-compatible, so that existing code doesn't break.

biosimulators_utils/sedml/validation.py

@@ -1715,7 +1715,7 @@ def validate_target(target, namespaces, context, language, model_id, model_etree
     return errors, warnings
 
 
-def validate_target_xpaths(targets, model_etree, attr='id'):
+def validate_target_xpaths(targets, model_etree, attr='id', separator=None):
     """ Validate that the target of each model change or variable matches one object in
     an XML-encoded model and, optionally, return the value of one of its attributes
 
@@ -1736,6 +1736,17 @@ def validate_target_xpaths(targets, model_etree, attr='id'):
                 x_path, _, _ = x_path.rpartition('/@')
             x_path_attrs[target.target] = validate_xpaths_ref_to_unique_objects(
                 model_etree, [x_path], target.target_namespaces, attr=attr)[x_path]
+    if separator is None:
+        return x_path_attrs
+    for xpath in x_path_attrs:
+        xpath_list = xpath.split("@" + attr + "=")
+        if len(xpath_list) < 3:
+            continue
+        combined_id = ""
+        for i in range(1, len(xpath_list)-1):
+            combined_id = combined_id + xpath_list[i].split(']')[0][1:-1] + separator
+        x_path_attrs[xpath] = combined_id + x_path_attrs[xpath]
+
     return x_path_attrs