feat: add Text.from/toList (#676)

CHANGELOG.md

@@ -1,5 +1,7 @@
 ## 0.13.x
 
+* Added `Text.fromList` and `Text.toList` functions (#676).
+
 * Added `Text.fromArray` and `Text.fromVarArray` functions (#674).
 
 ## 0.13.4

src/Text.mo

@@ -23,6 +23,7 @@
 import Char "Char";
 import Iter "Iter";
 import Hash "Hash";
+import List "List";
 import Stack "Stack";
 import Prim "mo:⛔";
 
@@ -139,6 +140,34 @@ module {
     return r
   };
 
+  /// Create a text from a character list.
+  /// Example:
+  /// ```motoko include=initialize
+  /// fromList(?('H', ?('e', ?('l', ?('l', ?('o', null))))));
+  /// // => "Hello"
+  /// ```
+  ///
+  /// Runtime: O(size cs)
+  /// Space: O(size cs)
+  public func fromList(cs : List.List<Char>) : Text = fromIter(List.toIter cs);
+
+  /// Create a character list from a text.
+  /// Example:
+  /// ```motoko include=initialize
+  /// toList("Hello");
+  /// // => ?('H', ?('e', ?('l', ?('l', ?('o', null)))))
+  /// ```
+  ///
+  /// Runtime: O(t.size())
+  /// Space: O(t.size())
+  public func toList(t : Text) : List.List<Char> {
+    var acc : List.List<Char> = null;
+    for (c in t.chars()) {
+        acc := ?(c, acc)
+    };
+    List.reverse acc
+  };
+
   /// Returns the number of characters in the given `Text`.
   ///
   /// Equivalent to calling `t.size()` where `t` is a `Text` value.

test/Text.test.mo

@@ -1053,6 +1053,24 @@ run(
   )
 );
 
+run(
+  suite(
+    "list-conversions",
+    [
+      test(
+        "toList-example",
+        Text.toList("Café"),
+        M.equals(T.list<Char>(T.charTestable, ?('C', ?('a', ?('f', ?('é', null)))))),
+      ),
+      test(
+        "fromList-example",
+        Text.fromList(?('H', ?('e', ?('l', ?('l', ?('o', null)))))),
+        M.equals(T.text "Hello")
+      )
+    ]
+  )
+);
+
 run(
   suite(
     "text-toLowercase",