Helper function for choosing a child group default attribute.

.vscode/settings.json

@@ -11,7 +11,9 @@
     },
     "editor.defaultFormatter": "charliermarsh.ruff"
   },
-  "python.testing.pytestArgs": ["tests"],
+  "python.testing.pytestArgs": [
+    "tests"
+  ],
   "python.testing.unittestEnabled": false,
   "python.testing.pytestEnabled": true
 }

src/pynxtools/dataconverter/helpers.py

@@ -921,3 +921,186 @@ def nested_dict_to_slash_separated_path(
             nested_dict_to_slash_separated_path(val, flattened_dict, path)
         else:
             flattened_dict[path] = val
+
+
+def dump_possible_groups_for_default_keys(
+    concept,
+    dflt_key_to_grp_li,
+    special_default_key_to_grp_li,
+    concept_level,
+    group_part,
+    group_name,
+):
+    """ """
+
+    # root level default
+    if concept_level == 0:
+        default_key = concept + "/@default"
+        if not special_default_key_to_grp_li.get("root", None):
+            special_default_key_to_grp_li["root"] = {default_key: []}
+        special_default_key_to_grp_li["root"][default_key].append(group_name)
+
+    # entry level default
+    elif concept_level == 1:
+        default_key = concept + "/@default"
+        if not special_default_key_to_grp_li.get("entry", None):
+            special_default_key_to_grp_li["entry"] = {default_key: None}
+        # Assuming multiple entries
+        if not special_default_key_to_grp_li["entry"].get(default_key, None):
+            special_default_key_to_grp_li["entry"][default_key] = {
+                "data": [],
+                "other": [],
+            }
+
+        if group_part.startswith("DATA"):
+            special_default_key_to_grp_li["entry"][default_key]["data"].append(
+                group_name
+            )
+        else:
+            special_default_key_to_grp_li["entry"][default_key]["other"].append(
+                group_name
+            )
+
+    else:
+        default_key = concept + "/@default"
+        if not dflt_key_to_grp_li.get(default_key, None):
+            dflt_key_to_grp_li[default_key] = {"data": [], "other": []}
+        if group_part.startswith("DATA"):
+            dflt_key_to_grp_li[default_key]["data"].append(group_name)
+        else:
+            dflt_key_to_grp_li[default_key]["other"].append(group_name)
+
+
+def set_default_from_key_grp_list_data(
+    template,
+    dflt_key_to_grp_li,
+    special_default_key_to_grp_li,
+    dflt_key_to_exist_grp,
+):
+    """Set default attribute for each group of Nexus file.
+
+    Each group will have a /@default attrubute refering the immediate child group in a
+    NeXus definition chain.
+
+    If the default attribute already refers to a group in the template that will
+    be persisted.
+
+    For root level attribute, the default will be first entry, if attribute is already empty.
+
+    For default attribute in the entry, NXdata group will dominate over other groups.
+    e.g. /@default = "entry1"
+        /entry1/@default = "data1"
+
+    Parameters
+    ----------
+    template : Template
+        Template from filled with datafile and eln.
+    dflt_key_to_grp_li : dict[str, dict[str, list]]
+        defalut attribute key to the list of immediate child group.
+    special_default_key_to_grp_li : dict[str, dict[str, dict[str, list]]]
+        special dict for root and entry.
+    dflt_key_to_exist_grp : dict[str, str]
+        defalut attribute key to the group set by reader.
+    """
+    for deflt_key, value in dflt_key_to_grp_li.items():
+        pre_defalt_grp = dflt_key_to_exist_grp.get(deflt_key, None)
+        # Verify if user added the group here
+        if pre_defalt_grp:
+            if pre_defalt_grp in value["data"] or pre_defalt_grp in value["other"]:
+                continue
+
+        else:
+            if value["data"]:
+                template[deflt_key] = value["data"][0]
+            elif value["other"]:
+                template[deflt_key] = value["other"][0]
+
+    for key, value in special_default_key_to_grp_li.items():
+        if key == "root":
+            if not dflt_key_to_exist_grp.get("/@default", None):
+                template["/@default"] = value["/@default"][0]
+
+        elif key == "entry":
+            # For muliple entries
+            for entry_defalt_key, entry_value in value.items():
+                # check already default set by reader
+                if dflt_key_to_exist_grp.get(entry_defalt_key, None):
+                    continue
+                if entry_value["data"]:
+                    template[entry_defalt_key] = entry_value["data"][0]
+                else:
+                    template[entry_defalt_key] = entry_value["other"][0]
+
+
+def set_default_from_child_group(template):
+    """Set default attribute for each group of Nexus file.
+
+    Each group will have a /@default attrubute refering the immediate child group in a
+    NeXus definition chain.
+
+    If the default attribute already refers to a group in the template that will
+    be persisted.
+
+    For root level attribute, the default will be first entry, if attribute is already empty.
+
+    For default attribute in the entry, NXdata group will dominate over other groups.
+    e.g. /@default = "entry1"
+        /entry1/@default = "data1"
+
+    Parameters
+    ----------
+    template : Template
+        Template from filled with datafile and eln.
+    """
+    # defalut attribute key to the list of immediate child group
+    dflt_key_to_grp_li: Optional[dict[str, list]] = {}
+    # special dict for root and entry
+    special_default_key_to_grp_li: Optional[dict[str, dict[str, dict[str, list]]]] = {}
+    # defalut attribute key to the group set by reader
+    dflt_key_to_exist_grp: dict[str, str] = {}
+
+    # "/abc[DATA]/XYe[anything]/mnf[MNYZ]/anything" -> ['DATA', 'anything', 'MNYZ']
+    pattern = r"\[(.*?)\]"
+
+    for template_concept, val in template.items():
+        if template_concept.endswith("/@default") and val:
+            dflt_key_to_exist_grp[template_concept] = val
+            continue
+
+        groups_list = template_concept.split("/")[1:]  # skip empty string
+
+        # skip other attributes like @units, @versions and so on
+        if groups_list[-1].startswith("@"):
+            continue
+        # Assume complete key refers to a field
+        # If key refers to a group, last chain group will be handled from other keys
+        else:
+            groups_list = groups_list[0:-1]
+
+        if not groups_list:
+            continue
+        concept = ""
+
+        for ind, group in enumerate(groups_list):
+            grp_name = re.findall(pattern, group)
+            if grp_name:
+                grp_name = grp_name[0]
+            else:
+                grp_name = group
+            dump_possible_groups_for_default_keys(
+                concept,
+                dflt_key_to_grp_li,
+                special_default_key_to_grp_li,
+                ind,
+                group,
+                grp_name,
+            )
+
+            concept = concept + "/" + group
+
+    set_default_from_key_grp_list_data(
+        template,
+        dflt_key_to_grp_li,
+        special_default_key_to_grp_li,
+        dflt_key_to_exist_grp,
+    )

tests/dataconverter/test_helpers.py

@@ -24,11 +24,10 @@
 
 import numpy as np
 import pytest
-from setuptools import distutils
-
 from pynxtools.dataconverter import helpers
 from pynxtools.dataconverter.template import Template
 from pynxtools.dataconverter.validation import validate_dict_against
+from setuptools import distutils
 
 
 def remove_optional_parent(data_dict: Template):
@@ -641,3 +640,78 @@ def test_warning_on_definition_changed_by_reader(caplog):
 
     assert "/ENTRY[entry]/definition" in template.keys()
     assert template["/ENTRY[entry]/definition"] == "NXtest"
+
+
+# TODO add nxdata in temp_dict example
+@pytest.mark.parametrize(
+    "temp_dict",
+    [
+        {
+            "/ENTRY[entry1]/NXODD_name[nxodd_name]/float_value": 2.0,
+            "/ENTRY[entry1]/NXODD_name[nxodd_name_2]/float_value": 8.0,
+            "/ENTRY[entry1]/NXODD_name[nxodd_name_2]/DATA[grp_data1]/data1": [
+                3,
+                5,
+                6,
+            ],
+            "/ENTRY[entry1]/NXODD_name[nxodd_name_2]/DATA[grp_data2]/data2": [
+                3,
+                5,
+                6,
+            ],
+            "/ENTRY[entry2]/@default": "nxodd_name_2",
+            "/ENTRY[entry2]/NXODD_name[nxodd_name]/float_value": 2.0,
+            "/ENTRY[entry2]/NXODD_name[nxodd_name_2]/float_value": 8.0,
+            "/ENTRY[entry2]/NXODD_name[nxodd_name_2]/INSTRUMENT[instrument]/DATA[data]/float_value": 8.0,
+            "/ENTRY[entry2]/NXODD_name[nxodd_name_2]/INSTRUMENT[instrument]/DATA[data1]/float_value": 8.0,
+        }
+    ],
+)
+def test_set_default_attr_in_group(temp_dict):
+    """Test default attriute that consider child group.
+    Parameters
+    ----------
+    template : Template
+    """
+    template = Template(temp_dict)
+    assert (
+        "/@default" not in template
+    ), "To test the root level /@default should be empty."
+    assert (
+        "/ENTRY[entry1]/@default" not in template
+    ), "To test default attribute, entry attribute should be empty."
+
+    helpers.set_default_from_child_group(template)
+    assert template["/@default"] in [
+        "entry1",
+        "entry2",
+    ], "To test the root level /@default should be empty."
+
+    assert template["/ENTRY[entry1]/@default"] in [
+        "nxodd_name",
+        "nxodd_name_2",
+    ], "To test default attribute, entry attribute should be empty."
+    assert template["/ENTRY[entry1]/NXODD_name[nxodd_name_2]/@default"] in [
+        "grp_data1",
+        "grp_data2",
+    ], "To test default attribute, entry attribute should be empty."
+
+    assert (
+        "/ENTRY[entry1]/NXODD_name[nxodd_name_2]/DATA[data2]/data2/@default"
+        not in template
+    ), (
+        "Group can not have a default attribute refering any field,"
+        " unless it is not supplied by reader."
+    )
+    assert (
+        template["/ENTRY[entry2]/@default"] == "nxodd_name_2"
+    ), "Default attribute supplied by reader can not be overwritten."
+    assert (
+        template["/ENTRY[entry2]/NXODD_name[nxodd_name_2]/@default"] == "instrument"
+    ), "Default attribute supplied by reader can not be overwritten."
+    assert template[
+        "/ENTRY[entry2]/NXODD_name[nxodd_name_2]/INSTRUMENT[instrument]/@default"
+    ] in [
+        "data",
+        "data1",
+    ], "Default attribute supplied by reader can not be overwritten."