Merge pull request #245 from DerwenAI/storage_plugin

unbinding a SPARQL query, to help troubleshoot integration with Oxrdflib

changelog.txt

@@ -1,10 +1,11 @@
 # `kglab` changelog
 
-## 0.5.?
+## 0.6.?
 
-2022-03-??
+2022-??-??
 
-  * ???
+  * support for substituting the binding variables into a SPARQL query
+  * add a NumPy-backed `RDFlib.Store` plugin
 
 
 ## 0.5.3
@@ -20,7 +21,7 @@
 
   * bump up versions of dependencies to fit Py 3.7+
   * improve testing based on pytest; kudos @Mec-iS
-  * allow configuration for rdflib.Store plugins
+  * allow configuration for `RDFlib.Store` plugins
 
 
 ## 0.5.1
@@ -190,7 +191,7 @@
 2020-12-06
 
   * added `pySHACL` examples
-  * resolved Google Colab errors registering the `rdflib-jsonld` plugin
+  * resolved Google Colab errors registering the `RDFlib-jsonld` plugin
   * comparing timing info across serialization methods
   * simplified the example notebook naming convention
 

kglab/kglab.py

@@ -12,6 +12,7 @@
 import io
 import json
 import pathlib
+import re
 import traceback
 import typing
 
@@ -1180,6 +1181,39 @@ def n3fy_row (
         return bindings
 
 
+    @classmethod
+    def unbind_sparql (
+        cls,
+        sparql: str,
+        bindings: dict,
+        *,
+        preamble: str = "",
+        ) -> str:
+        """
+Substitute the _binding variables_ into the text of a SPARQL query,
+to obviate the need for binding variables specified separately.
+This can be helpful for debugging, or for some query engines that
+may not have full SPARQL support yet.
+
+    sparql:
+text for the SPARQL query
+
+    bindings:
+variable bindings
+
+    returns:
+a string of the expanded SPARQL query
+        """
+        sparql_meta, sparql_body = re.split(r"\s*WHERE\s*\{", sparql, maxsplit=1)
+
+        for var in sorted(bindings.keys(), key=lambda x: len(x), reverse=True):  # pylint: disable=W0108
+            pattern = re.compile("(\?" + var + ")(\W)")  # pylint: disable=W1401
+            bind_val = "<" + str(bindings[var]) + ">\\2"
+            sparql_body = re.sub(pattern, bind_val, sparql_body)
+
+        return "".join([preamble, sparql_meta, " WHERE {", sparql_body]).strip()
+
+
     ######################################################################
     ## SHACL validation