add string join overloads for ReadOnlySpan (#276)

Author: SimonCropp

apiCount.include.md

@@ -1 +1 @@
-**API count: 437**
+**API count: 441**

api_list.include.md

@@ -577,8 +577,12 @@
 #### StringPolyfill
 
  * `string Join(char, object[])` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-char-system-object()))
+ * `string Join(char, ReadOnlySpan<object?>)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-char-system-readonlyspan((system-object))))
+ * `string Join(char, ReadOnlySpan<string?>)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-char-system-readonlyspan((system-string))))
  * `string Join(char, string?[], int, int)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-char-system-string()-system-int32-system-int32))
  * `string Join(char, string[])` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-char-system-string()))
+ * `string Join(string, ReadOnlySpan<object?>)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-string-system-readonlyspan((system-object))))
+ * `string Join(string, ReadOnlySpan<string?>)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-string-system-readonlyspan((system-string))))
  * `string Join<T>(char, IEnumerable<T>)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join-1(system-char-system-collections-generic-ienumerable((-0))))
 
 

readme.md

@@ -12,7 +12,7 @@ The package targets `netstandard2.0` and is designed to support the following ru
  * `net5.0`, `net6.0`, `net7.0`, `net8.0`, `net9.0`
 
 
-**API count: 437**<!-- singleLineInclude: apiCount. path: /apiCount.include.md -->
+**API count: 441**<!-- singleLineInclude: apiCount. path: /apiCount.include.md -->
 
 
 **See [Milestones](../../milestones?state=closed) for release notes.**
@@ -1046,8 +1046,12 @@ The class `Polyfill` includes the following extension methods:
 #### StringPolyfill
 
  * `string Join(char, object[])` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-char-system-object()))
+ * `string Join(char, ReadOnlySpan<object?>)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-char-system-readonlyspan((system-object))))
+ * `string Join(char, ReadOnlySpan<string?>)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-char-system-readonlyspan((system-string))))
  * `string Join(char, string?[], int, int)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-char-system-string()-system-int32-system-int32))
  * `string Join(char, string[])` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-char-system-string()))
+ * `string Join(string, ReadOnlySpan<object?>)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-string-system-readonlyspan((system-object))))
+ * `string Join(string, ReadOnlySpan<string?>)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-string-system-readonlyspan((system-string))))
  * `string Join<T>(char, IEnumerable<T>)` [reference](https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join-1(system-char-system-collections-generic-ienumerable((-0))))
 
 

src/Polyfill/StringPolyfill.cs

@@ -3,6 +3,7 @@
 
 namespace Polyfills;
 
+using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
@@ -18,7 +19,7 @@ static partial class StringPolyfill
     /// Concatenates an array of strings, using the specified separator between each member.
     /// </summary>
     //Link: https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-char-system-string())
-    public static string Join(char separator, string[] values) =>
+    public static string Join(char separator, params string[] values) =>
 #if NETSTANDARD2_0 || NETFRAMEWORK
         string.Join(new([separator]), values);
 #else
@@ -29,13 +30,59 @@ public static string Join(char separator, string[] values) =>
     /// Concatenates the string representations of an array of objects, using the specified separator between each member.
     /// </summary>
     //Link: https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-char-system-object())
-    public static string Join(char separator, object[] values) =>
+    public static string Join(char separator, params object[] values) =>
 #if NETSTANDARD2_0 || NETFRAMEWORK
         string.Join(new([separator]), values);
 #else
         string.Join(separator, values);
 #endif
 
+#if FeatureMemory
+    /// <summary>
+    /// Concatenates the string representations of a span of objects, using the specified separator between each member.
+    /// </summary>
+    //Link: https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-char-system-readonlyspan((system-object)))
+    public static string Join(char separator, scoped ReadOnlySpan<object?> values) =>
+#if NET9_0_OR_GREATER
+        string.Join(separator, values);
+#else
+        Join(separator, values.ToArray());
+#endif
+
+    /// <summary>
+    /// Concatenates a span of strings, using the specified separator between each member.
+    /// </summary>
+    //Link: https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-char-system-readonlyspan((system-string)))
+    public static string Join(char separator, scoped ReadOnlySpan<string?> values) =>
+#if NET9_0_OR_GREATER
+        string.Join(separator, values);
+#else
+        Join(separator, values.ToArray());
+#endif
+
+    /// <summary>
+    /// Concatenates the string representations of a span of objects, using the specified separator between each member.
+    /// </summary>
+    //Link: https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-string-system-readonlyspan((system-object)))
+    public static string Join(string separator, scoped ReadOnlySpan<object?> values) =>
+#if NET9_0_OR_GREATER
+        string.Join(separator, values);
+#else
+        string.Join(separator, values.ToArray());
+#endif
+
+    /// <summary>
+    /// Concatenates a span of strings, using the specified separator between each member.
+    /// </summary>
+    //Link: https://learn.microsoft.com/en-us/dotnet/api/system.string.join#system-string-join(system-string-system-readonlyspan((system-string)))
+    public static string Join(string separator, scoped ReadOnlySpan<string?> values) =>
+#if NET9_0_OR_GREATER
+        string.Join(separator, values);
+#else
+        string.Join(separator, values.ToArray());
+#endif
+#endif
+
     /// <summary>
     /// Concatenates the specified elements of a string array, using the specified separator between each element.
     /// </summary>