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introduced different result orders, prepared release 1.1.0 (#4)
* introduced different result orders * prepared release 1.1.0
1 parent 2a3e865 commit 2e07510

7 files changed

Lines changed: 664 additions & 43 deletions

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‎README.md‎

Lines changed: 35 additions & 17 deletions
Original file line numberDiff line numberDiff line change
@@ -11,29 +11,14 @@ B: c b a b a c
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To do this, we use the following code:
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```csharp
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// using spkl.Diffs;
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string[] a = new[] { "a", "b", "c", "a", "b", "b", "a" };
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string[] b = new[] { "c", "b", "a", "b", "a", "c" };
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MyersDiff<string> diff = new MyersDiff<string>(a, b);
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```
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Using generic typing, you can diff all sorts of types. You can also customize which values are considered equal by specifying a third constructor parameter (IEqualityComparer&lt;T&gt;).
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There are two methods to access the results: `GetResult()` and `GetEditScript()`.
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### GetResult()
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`GetResult()` returns the resulting diff as a sequence of tuples that represent lines. In this case, the return value would look like this:
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| ResultType | AItem | BItem |
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|------------|-------|-------|
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| A | a | |
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| B | | c |
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| Both | b | b |
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| A | c | |
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| Both | a | a |
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| Both | b | b |
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| A | b | |
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| Both | a | a |
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| B | | c |
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This is similar to how the result would be displayed in a visual comparison application. The AItem and BItem columns contain sequence A and B, respectively. The ResultType column shows whether a line contains a value from sequence A, B, or from both. You can see which values were matched with each other.
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There are two methods to access the results: `GetEditScript()` and `GetResult()`.
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### GetEditScript()
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`GetEditScript()` returns a sequence of edit instructions. You can understand these as instructions to follow to transform sequence A to sequence B. Every instruction contains four integers, a starting line number in A and B and the number of lines to add or remove. In this case, the return value would look like this:
@@ -65,3 +50,36 @@ To better understand this, let's follow these instructions:
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*(This adds the last "c")*
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Following these instructions, `abcabba` is transformed to `cbabac`.
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### GetResult()
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`GetResult()` returns the resulting diff as a sequence of tuples that represent lines. In this case, the return value would look like this:
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| ResultType | AItem | BItem |
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|------------|-------|-------|
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| A | a | |
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| B | | c |
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| Both | b | b |
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| A | c | |
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| Both | a | a |
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| Both | b | b |
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| A | b | |
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| Both | a | a |
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| B | | c |
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This is similar to how the result would be displayed in a visual comparison application. The AItem and BItem columns contain sequence A and B, respectively. The ResultType column shows whether a line contains a value from sequence A, B, or from both. You can see which values were matched with each other.
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### GetResult(ResultOrder)
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You can specify the order in which you want unmatched lines to appear by using the `GetResult(ResultOrder)` overload. To visualize this, we need to use a new example.
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```
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A: a b c
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B: x y
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```
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The following table shows how the result would be returned when specifying the different ResultOrder values AABB, BBAA, ABAB and BABA:
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| AABB | BBAA | ABAB | BABA |
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|:----:|:----:|:----:|:----:|
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| a - | - x | a - | - x |
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| b - | - y | - x | a - |
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| c - | a - | b - | - y |
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| - x | b - | - y | b - |
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| - y | c - | c - | c - |

‎src/Diffs.csproj‎

Lines changed: 3 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -11,8 +11,8 @@
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<Copyright>Copyright (c) 2021 Sebastian Fischer</Copyright>
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<RepositoryUrl>https://github.com/spkl/Diffs</RepositoryUrl>
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<AssemblyVersion>1.0.0.0</AssemblyVersion>
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<FileVersion>1.0.1.0</FileVersion>
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<Version>1.0.1</Version>
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<FileVersion>1.1.0.0</FileVersion>
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<Version>1.1.0</Version>
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<SignAssembly>true</SignAssembly>
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<AssemblyOriginatorKeyFile>..\keys\spkl.Diffs.snk</AssemblyOriginatorKeyFile>
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<DelaySign>false</DelaySign>
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This project uses Semantic Versioning (https://semver.org/).</Description>
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<PackageTags>diff diffs difference algorithm ses shortest edit script myers</PackageTags>
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<GeneratePackageOnBuild>false</GeneratePackageOnBuild>
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<PackageReleaseNotes>- Added documentation comments to all public types and methods to explain usage.
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- Fixed issue where the comparer passed into the MyersDiff&lt;T&gt; constructor was ignored.</PackageReleaseNotes>
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<PackageReleaseNotes>- Introduced new GetResult overload to customize the preferred order of unmatched lines.</PackageReleaseNotes>
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</PropertyGroup>
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<ItemGroup>

src/MyersDiff.cs renamed to src/MyersDiff{T}.cs

Lines changed: 62 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -86,8 +86,43 @@ private bool AreEqual(int aIndex, int bIndex)
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/// BItem: The item from sequence B, this is the default value/null if resultType is <see cref="ResultType.A"/>.
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/// </summary>
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/// <returns>An enumerable of diff lines containing one unmatched or two matched items.</returns>
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/// <remarks>This is this equal to calling <see cref="GetResult(ResultOrder)"/> with <see cref="ResultOrder.AABB"/>.</remarks>
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public IEnumerable<(ResultType ResultType, T AItem, T BItem)> GetResult()
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{
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return this.GetResult(ResultOrder.AABB);
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}
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/// <summary>
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/// Gets the calculated diff result in the form of matched items/lines:
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/// ResultType: Specifies whether the line includes only an item from A, from B or from both sequences.
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/// AItem: The item from sequence A; this is the default value/null if resultType is <see cref="ResultType.B"/>.
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/// BItem: The item from sequence B, this is the default value/null if resultType is <see cref="ResultType.A"/>.
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/// </summary>
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/// <param name="order">The order in which unmatched items/lines are returned.</param>
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/// <returns>An enumerable of diff lines containing one unmatched or two matched items.</returns>
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public IEnumerable<(ResultType ResultType, T AItem, T BItem)> GetResult(ResultOrder order)
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{
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ResultType GetPreferredNext(ResultType current)
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{
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if (current == ResultType.Both)
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{
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// A first or B first
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return (order == ResultOrder.ABAB || order == ResultOrder.AABB) ? ResultType.A : ResultType.B;
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}
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if (order == ResultOrder.AABB || order == ResultOrder.BBAA)
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{
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// Section mode - keep same side.
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return current;
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}
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else
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{
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// Line mode - switch side.
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return current == ResultType.A ? ResultType.B : ResultType.A;
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}
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}
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ResultType preferredNext = GetPreferredNext(ResultType.Both);
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int currentA = 0, currentB = 0;
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while (currentA < this.aRemoved.Length || currentB < this.bAdded.Length)
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{
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yield return (ResultType.Both, this.aValues[currentA], this.bValues[currentB]);
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currentA++;
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currentB++;
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preferredNext = GetPreferredNext(ResultType.Both);
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}
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else if (this.aRemoved[currentA])
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else if (preferredNext == ResultType.A)
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{
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yield return (ResultType.A, this.aValues[currentA], default(T));
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currentA++;
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if (this.aRemoved[currentA])
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{
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yield return (ResultType.A, this.aValues[currentA], default(T));
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currentA++;
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preferredNext = GetPreferredNext(ResultType.A);
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}
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else if (this.bAdded[currentB])
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{
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yield return (ResultType.B, default(T), this.bValues[currentB]);
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currentB++;
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preferredNext = GetPreferredNext(ResultType.B);
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}
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}
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else if (this.bAdded[currentB])
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else // preferredNext == ResultType.B
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{
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yield return (ResultType.B, default(T), this.bValues[currentB]);
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currentB++;
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if (this.bAdded[currentB])
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{
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yield return (ResultType.B, default(T), this.bValues[currentB]);
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currentB++;
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preferredNext = GetPreferredNext(ResultType.B);
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}
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else if (this.aRemoved[currentA])
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{
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yield return (ResultType.A, this.aValues[currentA], default(T));
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currentA++;
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preferredNext = GetPreferredNext(ResultType.A);
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}
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}
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}
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else if (currentA < this.aRemoved.Length)

‎src/ResultOrder.cs‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,25 @@
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namespace spkl.Diffs
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{
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/// <summary>
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/// Determines in which order the <see cref="MyersDiff{T}.GetResult(ResultOrder)"/> method returns items.
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/// </summary>
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public enum ResultOrder
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{
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/// <summary>
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/// Items are ordered in alternating sections, first A, then B.
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/// </summary>
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AABB,
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/// <summary>
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/// Items are ordered in alternating sections, first B, then A.
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/// </summary>
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BBAA,
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/// <summary>
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/// Items are ordered in alternating lines, first A, then B.
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/// </summary>
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ABAB,
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/// <summary>
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/// Items are ordered in alternating lines, first B, then A.
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/// </summary>
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BABA
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}
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}

‎test/MyersDiffClass.ReferenceCase.cs‎

Lines changed: 8 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -24,7 +24,13 @@ public string BString
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}
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}
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public (ResultType ResultType, string AItem, string BItem)[] Result { get; set; }
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public (ResultType ResultType, string AItem, string BItem)[] ResultAABB { get; set; }
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public (ResultType ResultType, string AItem, string BItem)[] ResultBBAA { get; set; }
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public (ResultType ResultType, string AItem, string BItem)[] ResultABAB { get; set; }
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public (ResultType ResultType, string AItem, string BItem)[] ResultBABA { get; set; }
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public (int LineA, int LineB, int CountA, int CountB)[] EditScript { get; set; }
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@@ -34,4 +40,4 @@ public override string ToString()
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}
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}
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}
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}
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}

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