From 17b2d0791b525b7946f186c8b250123a60374a44 Mon Sep 17 00:00:00 2001
From: Simon Gene Gottlieb <simon@gottliebtfreitag.de>
Date: Tue, 17 May 2022 09:36:29 +0200
Subject: [PATCH] [misc] improved doc and snippet for kmer_hash

Update test/snippet/search/views/kmer_hash.cpp
Update include/seqan3/search/views/kmer_hash.hpp

Co-authored-by: Svenja Mehringer <svenja.mehringer@gmail.com>
---
 include/seqan3/search/views/kmer_hash.hpp |  4 ++--
 test/snippet/search/views/kmer_hash.cpp   | 13 +++++++------
 test/snippet/search/views/kmer_hash.err   |  4 ++--
 3 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/include/seqan3/search/views/kmer_hash.hpp b/include/seqan3/search/views/kmer_hash.hpp
index 09ae64311b..8fdc63eba7 100644
--- a/include/seqan3/search/views/kmer_hash.hpp
+++ b/include/seqan3/search/views/kmer_hash.hpp
@@ -774,8 +774,8 @@ namespace seqan3::views
  *
  * See the \link views views submodule documentation \endlink for detailed descriptions of the view properties.
  *
- * \attention The Shape is defined from right to left. The mask 0b1101 applied to ACGT will return
- * the sequence AGT.
+ * \attention The Shape is defined from right to left! The mask 0b11111101 applied to "AGAAAATA" is 
+ * interpreted as "A.AAAATA" (and not "AGAAAA.A") and will return the hash value for "AAAAATA".
  *
  * ### Example
  *
diff --git a/test/snippet/search/views/kmer_hash.cpp b/test/snippet/search/views/kmer_hash.cpp
index 749d9c742a..ff7f36fc0d 100644
--- a/test/snippet/search/views/kmer_hash.cpp
+++ b/test/snippet/search/views/kmer_hash.cpp
@@ -15,12 +15,13 @@ int main()
 
     seqan3::debug_stream << (text | seqan3::views::kmer_hash(0b101_shape)) << '\n'; // [2,7,8,14,1]
 
-    // Note: the Shape is defined from right to left. The mask 0b1101 applied to ACGT will yield
-    // the same result as mask 0b111 applied to AGT.
+    // Attention: the Shape is defined from right to left! 
+    // The mask 0b11111101 applied to "AGAAAATA" ("A.AAAATA") will yield
+    // the same hash value as mask 0b1111111 applied to "AAAAATA".
     {
-        auto text1 = "ACGT"_dna4;
-        auto text2 = "AGT"_dna4;
-        seqan3::debug_stream << (text1 | seqan3::views::kmer_hash(0b1101_shape)) << '\n'; // [11]
-        seqan3::debug_stream << (text2 | seqan3::views::kmer_hash(0b111_shape)) << '\n';  // [11]
+        auto text1 = "AGAAAATA"_dna4;
+        auto text2 = "AAAAATA"_dna4;
+        seqan3::debug_stream << (text1 | seqan3::views::kmer_hash(0b11111101_shape)) << '\n'; // [12]
+        seqan3::debug_stream << (text2 | seqan3::views::kmer_hash(0b1111111_shape)) << '\n';  // [12]
     }
 }
diff --git a/test/snippet/search/views/kmer_hash.err b/test/snippet/search/views/kmer_hash.err
index d2f3e13684..18c85e7662 100644
--- a/test/snippet/search/views/kmer_hash.err
+++ b/test/snippet/search/views/kmer_hash.err
@@ -1,5 +1,5 @@
 [6,27,44,50,9]
 [6,27,44,50,9]
 [2,7,8,14,1]
-[11]
-[11]
+[12]
+[12]