Support chaining multiple result sets.

src/kuzu/queries.nim

@@ -147,14 +147,14 @@ func hasNext*( query: KuzuQueryResult ): bool =
 
 
 func getNext*( query: KuzuQueryResult ): KuzuFlatTuple =
-    ## Consume and return the next tuple result, or raise a KuzuIndexError
-    ## if at the end of the result set.
+    ## Consume and return the next tuple result, or raise a KuzuIterationError
+    ## if at the end of the result tuples.
     result = new KuzuFlatTuple
     if kuzu_query_result_get_next( addr query.handle, addr result.handle ) == KuzuSuccess:
         result.valid = true
         result.num_columns = query.num_columns
     else:
-        raise newException( KuzuIndexError, &"Query iteration past end." )
+        raise newException( KuzuIterationError, &"Query iteration past end of tuples." )
 
 
 func rewind*( query: KuzuQueryResult ) =
@@ -162,6 +162,32 @@ func rewind*( query: KuzuQueryResult ) =
     kuzu_query_result_reset_iterator( addr query.handle )
 
 
+func hasNextSet*( query: KuzuQueryResult ): bool =
+    ## Returns +true+ if there are more result sets to be consumed.
+    result = kuzu_query_result_has_next_query_result( addr query.handle )
+
+
+# Keeping this private, because it's only safe to call from within
+# an iterator -- overwriting a query variable with the next result
+# goes boom.
+func getNextSet( query: KuzuQueryResult ): KuzuQueryResult =
+    ## Consume and return the next query set result, or raise a KuzuIterationError
+    ## if at the end of sets.
+    result = new KuzuQueryResult
+    if kuzu_query_result_get_next_query_result( addr query.handle, addr result.handle ) == KuzuSuccess:
+        result.valid = true
+        result.getQueryMetadata()
+    else:
+        raise newException( KuzuIterationError, &"Query iteration past end of set." )
+
+
+iterator sets*( query: KuzuQueryResult ): KuzuQueryResult =
+    ## Iterate available query result sets, yielding to the block.
+    while query.hasNextSet:
+        yield query.getNextSet
+    # NOTE: There is no 'rewind' mechanism for result sets.
+
+
 iterator items*( query: KuzuQueryResult ): KuzuFlatTuple =
     ## Iterate available tuples, yielding to the block.
     while query.hasNext:

src/kuzu/types.nim

@@ -48,8 +48,9 @@ type
         keys*: seq[ string ]
     KuzuStructValue* = ref KuzuStructValueObj
 
-    KuzuException*  = object of CatchableError
-    KuzuQueryError* = object of KuzuException
-    KuzuIndexError* = object of KuzuException
-    KuzuTypeError*  = object of KuzuException
+    KuzuException*      = object of CatchableError
+    KuzuQueryError*     = object of KuzuException
+    KuzuIndexError*     = object of KuzuException
+    KuzuIterationError* = object of KuzuException
+    KuzuTypeError*      = object of KuzuException