feat: add String::concat_view

string/string.mbt

@@ -32,16 +32,16 @@ pub fn String::from_array(chars : Array[Char]) -> String {
 }
 
 ///|
-/// Concatenate strings.
+/// Concatenate strings by a string array view.
 /// 
 /// ```
-/// let s = @string.concat(["Hello", ", ", "world!"])
+/// let s = @string.concat_view(["Hello", ", ", "world!"][:])
 /// assert_eq!(s, "Hello, world!")
-/// let s = @string.concat(["a", "b", "c"], separator=",")
+/// let s = @string.concat_view(["a", "b", "c"][:], separator=",")
 /// assert_eq!(s, "a,b,c")
 /// ```
-pub fn String::concat(
-  strings : Array[String],
+pub fn String::concat_view(
+  strings : ArrayView[String],
   separator~ : String = ""
 ) -> String {
   let buf = StringBuilder::new()
@@ -64,6 +64,22 @@ pub fn String::concat(
   buf.to_string()
 }
 
+///|
+/// Concatenate strings by a string array.
+/// 
+/// ```
+/// let s = @string.concat(["Hello", ", ", "world!"])
+/// assert_eq!(s, "Hello, world!")
+/// let s = @string.concat(["a", "b", "c"], separator=",")
+/// assert_eq!(s, "a,b,c")
+/// ```
+pub fn String::concat(
+  strings : Array[String],
+  separator~ : String = ""
+) -> String {
+  String::concat_view(strings[:], separator~)
+}
+
 ///|
 /// Compare two strings.
 /// String with longer length is bigger.

string/string.mbti

@@ -8,6 +8,7 @@ package moonbitlang/core/string
 impl String {
   compare(String, String) -> Int
   concat(Array[String], separator~ : String = ..) -> String
+  concat_view(ArrayView[String], separator~ : String = ..) -> String
   contains(String, String) -> Bool
   contains_char(String, Char) -> Bool
   default() -> String

string/string_test.mbt

@@ -25,6 +25,15 @@ test "String::concat" {
   inspect!(String::concat([], separator=" "), content="")
 }
 
+test "String::concat_view" {
+  inspect!(String::concat_view(["123", "456"][:]), content="123456")
+  inspect!(
+    String::concat_view(["aaa", "bbb", "ccc"][1:3], separator=" "),
+    content="bbb ccc",
+  )
+  inspect!(String::concat_view([][:], separator=" "), content="")
+}
+
 test "default" {
   inspect!(@string.default())
 }