Implement ToStringView for Char

array/array_test.mbt

@@ -299,3 +299,13 @@ test "panic fill with invalid end" {
   let arr = [1, 2, 3, 4, 5]
   arr.fill(0, start=2, end=10)
 }
+
+///|
+test "Array::join with Char" {
+  let chars : Array[Char] = ['h', 'e', 'l', 'l', 'o']
+  let result = chars.join("")
+  inspect(result, content="hello")
+  let chars2 : Array[Char] = ['a', 'b', 'c']
+  let result2 = chars2.join(", ")
+  inspect(result2, content="a, b, c")
+}

string/pkg.generated.mbti

@@ -151,6 +151,7 @@ impl ToJson for StringView
 pub trait ToStringView {
   to_string_view(Self) -> StringView
 }
+impl ToStringView for Char
 impl ToStringView for String
 impl ToStringView for StringView
 

string/string_like.mbt

@@ -26,3 +26,9 @@ pub impl ToStringView for String with to_string_view(self) -> StringView {
 pub impl ToStringView for StringView with to_string_view(self) -> StringView {
   self
 }
+
+///|
+/// Implements ToStringView for Char, enabling operations like Array::join on Array[Char]
+pub impl ToStringView for Char with to_string_view(self) -> StringView {
+  [self]
+}

string/tostringview_char_demo_test.mbt

@@ -0,0 +1,41 @@
+// Copyright 2025 International Digital Economy Academy
+//
+// Licensed 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.
+
+///|
+test "ToStringView for Char - comprehensive demo" {
+  // Test 1: Simple join without separator
+  let chars1 : Array[Char] = ['h', 'e', 'l', 'l', 'o']
+  let result1 = chars1.join("")
+  inspect(result1, content="hello")
+
+  // Test 2: Join with separator
+  let chars2 : Array[Char] = ['a', 'b', 'c', 'd']
+  let result2 = chars2.join(", ")
+  inspect(result2, content="a, b, c, d")
+
+  // Test 3: Empty array
+  let chars3 : Array[Char] = []
+  let result3 = chars3.join("-")
+  inspect(result3, content="")
+
+  // Test 4: Single character
+  let chars4 : Array[Char] = ['x']
+  let result4 = chars4.join(" | ")
+  inspect(result4, content="x")
+
+  // Test 5: Unicode characters
+  let chars5 : Array[Char] = ['🌟', '✨', '🎉']
+  let result5 = chars5.join(" ")
+  inspect(result5, content="🌟 ✨ 🎉")
+}