Add basic tuple and value fetching from queries.

Add safeties for =destroy hooks.

FossilOrigin-Name: 2fae5297a0d0598cc3580777688b4f4307de008d4f379d2fb224c8a74cb9b708

tests/tuples/t_can_be_stringified.nim

@@ -0,0 +1,19 @@
+# vim: set et sta sw=4 ts=4 :
+
+discard """
+output: "okay!"
+"""
+
+import kuzu
+
+let db = newKuzuDatabase()
+let conn = db.connect
+
+var q = conn.query( "CREATE NODE TABLE Doop ( id SERIAL, thing STRING, PRIMARY KEY(id) )" )
+q = conn.query( "CREATE (d:Doop {thing: 'okay!'})" )
+q = conn.query( "MATCH (d:Doop) RETURN d.thing" )
+
+var tup = q.getNext
+
+echo $tup
+

tests/tuples/t_throws_exception_fetching_at_end.nim

@@ -0,0 +1,17 @@
+# vim: set et sta sw=4 ts=4 :
+
+import
+    std/re
+import kuzu
+
+let db = newKuzuDatabase()
+let conn = db.connect
+
+var q = conn.query( "CREATE NODE TABLE Doop ( id SERIAL, thing STRING, PRIMARY KEY(id) )" )
+q = conn.query( "MATCH (d:Doop) RETURN d.thing" )
+
+try:
+   discard q.getNext
+except KuzuQueryException as err:
+    assert err.msg.contains( re"""Unable to fetch next tuple.""" )
+

tests/tuples/t_throws_exception_invalid_index.nim

@@ -0,0 +1,20 @@
+# vim: set et sta sw=4 ts=4 :
+
+import
+    std/re
+import kuzu
+
+let db = newKuzuDatabase()
+let conn = db.connect
+
+var q = conn.query( "CREATE NODE TABLE Doop ( id SERIAL, thing STRING, PRIMARY KEY(id) )" )
+q = conn.query( "CREATE (d:Doop {thing: 'okay!'})" )
+q = conn.query( "MATCH (d:Doop) RETURN d.thing" )
+
+let tup = q.getNext
+
+try:
+    echo tup[22]
+except KuzuIndexException as err:
+    assert err.msg.contains( re"""Unable to fetch tuple value at idx 22.""" )
+