Lazy load definition entries when creating tags

hed/models/definition_dict.py

@@ -251,30 +251,22 @@ def _validate_contents(self, definition_tag, group, error_handler):
 
         return issues
 
-    def construct_def_tags(self, hed_string_obj):
-        """ Identify def/def-expand tag contents in the given string.
+    def get_definition_entry(self, def_tag):
+        """ Get the entry for a given def tag.
 
-        Parameters:
-            hed_string_obj(HedString): The hed string to identify definition contents in
-        """
-        for tag in hed_string_obj.get_all_tags():
-            self.construct_def_tag(tag)
-
-    def construct_def_tag(self, hed_tag):
-        """ Identify def/def-expand tag contents in the given HedTag.
+            Does not validate at all.
 
         Parameters:
-            hed_tag(HedTag): The hed tag to identify definition contents in
+            def_tag (HedTag): Source hed tag that may be a Def or Def-expand tag.
+
+        Returns:
+            def_entry(DefinitionEntry or None): The definition entry if it exists
         """
-        # Finish tracking down why parent is set incorrectly on def tags sometimes
-        # It should be ALWAYS set
-        if hed_tag.short_base_tag in {DefTagNames.DEF_ORG_KEY, DefTagNames.DEF_EXPAND_ORG_KEY}:
-            save_parent = hed_tag._parent
-            def_contents = self._get_definition_contents(hed_tag)
-            hed_tag._parent = save_parent
-            if def_contents is not None:
-                hed_tag._expandable = def_contents
-                hed_tag._expanded = hed_tag.short_base_tag == DefTagNames.DEF_EXPAND_ORG_KEY
+        tag_label, _, placeholder = def_tag.extension.partition('/')
+
+        label_tag_lower = tag_label.lower()
+        def_entry = self.defs.get(label_tag_lower)
+        return def_entry
 
     def _get_definition_contents(self, def_tag):
         """ Get the contents for a given def tag.

hed/models/hed_tag.py

@@ -1,6 +1,7 @@
 """ A single HED tag. """
 from hed.schema.hed_schema_constants import HedKey
 import copy
+from hed.models.model_constants import DefTagNames
 
 
 class HedTag:
@@ -46,8 +47,10 @@ def __init__(self, hed_string, hed_schema, span=None, def_dict=None):
         self.tag_terms = None  # tuple of all the terms in this tag Lowercase.
         self._calculate_to_canonical_forms(hed_schema)
 
+        self._def_entry = None
         if def_dict:
-            def_dict.construct_def_tag(self)
+            if self.short_base_tag in {DefTagNames.DEF_ORG_KEY, DefTagNames.DEF_EXPAND_ORG_KEY}:
+                self._def_entry = def_dict.get_definition_entry(self)
 
     def copy(self):
         """ Return a deep copy of this tag.
@@ -261,9 +264,20 @@ def expandable(self):
 
            This is primarily used for Def/Def-expand tags at present.
 
+           Lazily set the first time it's called.
+
         Returns:
             HedGroup or HedTag or None: Returns the expanded form of this tag.
         """
+        if self._expandable is None and self._def_entry:
+            save_parent = self._parent
+            tag_label, _, placeholder = self.extension.partition('/')
+
+            def_contents = self._def_entry.get_definition(self, placeholder_value=placeholder)
+            self._parent = save_parent
+            if def_contents is not None:
+                self._expandable = def_contents
+                self._expanded = self.short_base_tag == DefTagNames.DEF_EXPAND_ORG_KEY
         return self._expandable
 
     def is_column_ref(self):

hed/validator/hed_validator.py

@@ -75,9 +75,6 @@ def run_basic_checks(self, hed_string, allow_placeholders):
         issues += hed_string._calculate_to_canonical_forms(self._hed_schema)
         if check_for_any_errors(issues):
             return issues
-        # This is required so it can validate the tag a tag expands into
-        # e.g. checking units when a definition placeholder has units
-        self._def_validator.construct_def_tags(hed_string)
         issues += self._validate_individual_tags_in_hed_string(hed_string, allow_placeholders=allow_placeholders)
         issues += self._def_validator.validate_def_tags(hed_string, self)
         return issues