From d220e97b42c0931635d20242724f50e0d8fb4250 Mon Sep 17 00:00:00 2001
From: Graham Higgins <gjh@bel-epa.com>
Date: Sat, 25 Dec 2021 14:07:19 +0000
Subject: [PATCH] Fix for issue #272

---
 rdflib/plugins/sparql/__init__.py  |  2 +-
 rdflib/plugins/sparql/algebra.py   |  4 +--
 rdflib/plugins/sparql/processor.py |  9 +++++++
 rdflib/plugins/sparql/sparql.py    | 10 +++++++
 rdflib/plugins/sparql/update.py    |  2 +-
 test/test_sparql_prepare.py        | 43 ++++++++++++++++++++++++++++++
 6 files changed, 66 insertions(+), 4 deletions(-)
 create mode 100644 test/test_sparql_prepare.py

diff --git a/rdflib/plugins/sparql/__init__.py b/rdflib/plugins/sparql/__init__.py
index eb9230bf1..97d8c56aa 100644
--- a/rdflib/plugins/sparql/__init__.py
+++ b/rdflib/plugins/sparql/__init__.py
@@ -35,7 +35,7 @@
 from . import operators
 from . import parserutils
 
-from .processor import prepareQuery, processUpdate
+from .processor import prepareQuery, prepareUpdate, processUpdate
 
 assert parser
 assert operators
diff --git a/rdflib/plugins/sparql/algebra.py b/rdflib/plugins/sparql/algebra.py
index b3d1a3bae..805e62a80 100644
--- a/rdflib/plugins/sparql/algebra.py
+++ b/rdflib/plugins/sparql/algebra.py
@@ -13,7 +13,7 @@
 
 from rdflib import Literal, Variable, URIRef, BNode
 
-from rdflib.plugins.sparql.sparql import Prologue, Query
+from rdflib.plugins.sparql.sparql import Prologue, Query, Update
 from rdflib.plugins.sparql.parserutils import CompValue, Expr
 from rdflib.plugins.sparql.operators import (
     and_,
@@ -761,7 +761,7 @@ def translateUpdate(q, base=None, initNs=None):
 
         res.append(translateUpdate1(u, prologue))
 
-    return res
+    return Update(prologue, res)
 
 
 def translateQuery(q, base=None, initNs=None):
diff --git a/rdflib/plugins/sparql/processor.py b/rdflib/plugins/sparql/processor.py
index 84e8c8231..febb47758 100644
--- a/rdflib/plugins/sparql/processor.py
+++ b/rdflib/plugins/sparql/processor.py
@@ -26,6 +26,15 @@ def prepareQuery(queryString, initNs={}, base=None):
     return ret
 
 
+def prepareUpdate(updateString, initNs={}, base=None):
+    """
+    Parse and translate a SPARQL Update
+    """
+    ret = translateUpdate(parseUpdate(updateString), base, initNs)
+    ret._original_args = (updateString, initNs, base)
+    return ret
+
+
 def processUpdate(graph, updateString, initBindings={}, initNs={}, base=None):
     """
     Process a SPARQL Update Request
diff --git a/rdflib/plugins/sparql/sparql.py b/rdflib/plugins/sparql/sparql.py
index eedc9e746..526203c47 100644
--- a/rdflib/plugins/sparql/sparql.py
+++ b/rdflib/plugins/sparql/sparql.py
@@ -408,3 +408,13 @@ class Query:
     def __init__(self, prologue, algebra):
         self.prologue = prologue
         self.algebra = algebra
+
+
+class Update:
+    """
+    A parsed and translated update
+    """
+
+    def __init__(self, prologue, algebra):
+        self.prologue = prologue
+        self.algebra = algebra
diff --git a/rdflib/plugins/sparql/update.py b/rdflib/plugins/sparql/update.py
index f979c3872..ef4b46b95 100644
--- a/rdflib/plugins/sparql/update.py
+++ b/rdflib/plugins/sparql/update.py
@@ -273,7 +273,7 @@ def evalUpdate(graph, update, initBindings={}):
 
     """
 
-    for u in update:
+    for u in update.algebra:
 
         initBindings = dict((Variable(k), v) for k, v in initBindings.items())
 
diff --git a/test/test_sparql_prepare.py b/test/test_sparql_prepare.py
new file mode 100644
index 000000000..3a0f51324
--- /dev/null
+++ b/test/test_sparql_prepare.py
@@ -0,0 +1,43 @@
+import os
+from rdflib.plugins.sparql import prepareUpdate, prepareQuery
+from rdflib.namespace import FOAF
+from rdflib import (
+    Graph,
+    URIRef,
+)
+
+
+def test_prepare_update():
+
+    q = prepareUpdate(
+        """\
+PREFIX dc: <http://purl.org/dc/elements/1.1/>
+INSERT DATA
+{ <http://example/book3> dc:title "A new book" ;
+                         dc:creator "A.N.Other" .
+ } ;
+""",
+        initNs={},
+    )
+
+    g = Graph()
+    g.update(q, initBindings={})
+    assert len(g) == 2
+
+
+def test_prepare_query():
+
+    q = prepareQuery(
+        "SELECT ?name WHERE { ?person foaf:knows/foaf:name ?name . }",
+        initNs={"foaf": FOAF},
+    )
+
+    g = Graph()
+    g.parse(
+        location=os.path.join(os.path.dirname(__file__), "..", "examples", "foaf.n3"),
+        format="n3",
+    )
+
+    tim = URIRef("http://www.w3.org/People/Berners-Lee/card#i")
+
+    assert len(list(g.query(q, initBindings={"person": tim}))) == 50