[GitHub] [arrow] hermanschaaf commented on a diff in pull request #34806: GH-34790: [Go]: Add array.Diff()

["hermanschaaf (via GitHub)" <gi...@apache.org>]

hermanschaaf commented on code in PR #34806:
URL: https://github.com/apache/arrow/pull/34806#discussion_r1156006866


##########
go/arrow/array/diff.go:
##########
@@ -0,0 +1,276 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package array
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/apache/arrow/go/v12/arrow"
+	"github.com/apache/arrow/go/v12/arrow/memory"
+)
+
+// Diff compares two arrays, returning an edit script which expresses the difference
+// between them. The edit script can be applied to the base array to produce the target.
+//
+// An edit script is an array of struct(insert bool, run_length int64).
+// Each element of "insert" determines whether an element was inserted into (true)
+// or deleted from (false) base. Each insertion or deletion is followed by a run of
+// elements which are unchanged from base to target; the length of this run is stored
+// in "run_length". (Note that the edit script begins and ends with a run of shared
+// elements but both fields of the struct must have the same length. To accommodate this
+// the first element of "insert" should be ignored.)
+//
+// For example for base "hlloo" and target "hello", the edit script would be
+// [
+//
+//	{"insert": false, "run_length": 1}, // leading run of length 1 ("h")
+//	{"insert": true, "run_length": 3}, // insert("e") then a run of length 3 ("llo")
+//	{"insert": false, "run_length": 0} // delete("o") then an empty run
+//
+// ]
+//
+// base: baseline for comparison
+// target: an array of identical type to base whose elements differ from base's
+// mem: memory to store the result will be allocated from this memory pool
+func Diff(base, target arrow.Array, mem memory.Allocator) (*Struct, error) {

Review Comment:
   I don't think so, and I'm happy to change it to native Go structs if you think that's the way to go? I only used an Arrow Struct to keep the interface the same as in in the C++ implementation. 



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