Merge branch 'develop_carsten' into develop

docs/source/userdoc/overview.md

@@ -11,6 +11,8 @@ In Pyerk there are the following kinds of keys:
 - d) prefixed name-labeled key like `"bi__R1234__my_relation"`
 - e) index-labeld key like `"R1234['my relation']"`
 
+Note: prefixed and name-labled keys can optionally have a language indicator. Examples: ``"bi__R1__de"`` or `"R1__has_label__fr"`.
+
 Also, the leading character indicates the entity type (called `EType` in the code): `I` → item, `R` → relation.
 
 The usage of these syntax variants depens on the context.

src/pyerk/auxiliary.py

@@ -118,7 +118,10 @@ class PyERKError(Exception):
  """
  raised in situations where some ERK-specific conditions are violated
  """
+ pass
+
 
+class MultilingualityError(PyERKError):
  pass
 
 
@@ -151,6 +154,10 @@ class InvalidGeneralKeyError(PyERKError):
  pass
 
 
+class InconsistentLabelError(PyERKError):
+ pass
+
+
 # used for syntactically correct keys which could not be found
 class ShortKeyNotFoundError(PyERKError):
  pass

src/pyerk/builtin_entities.py

@@ -1282,7 +1282,12 @@ def _get_subscope(self, name: str):
  assert isinstance(name, str)
  scope_rels: list = self.get_inv_relations("R21__is_scope_of", return_subj=True)
 
- res = [rel for rel in scope_rels if rel.R1 == name or rel.R1 == f"scp__{name}"]
+ res = []
+ for rel in scope_rels:
+ assert isinstance(rel.R1, core.Literal)
+ r1 = rel.R1.value
+ if r1 == name or r1 == f"scp__{name}":
+ res.append(rel)
 
  if len(res) == 0:
  msg = f"no scope with name {name} could be found"
@@ -2301,7 +2306,7 @@ def set_multiple_statements(subjects: Union[list, tuple], predicate: Relation, o
  "specifies that the subject should be threated according to the mode (int number) when constructing the "
  "prototype graph of an I41__semantic_rule; Modes: 0 -> normal; 1 -> ignore node, 2 -> relation statement, "
  "3 -> variable literal, 4 -> function-anchor; 5 -> create_asserted_statement_only_if_new; "
- "currently '2' is not implemented.",
+ "currently '2' is not implemented."
  ),
  R8__has_domain_of_argument_1=I1["general item"],
  R11__has_range_of_result=int,