RString utf8 fixes

src/class/string.rs

@@ -13,6 +13,7 @@ pub struct RString {
 
 impl RString {
     /// Creates a new instance of Ruby `String` containing given `string`.
+    /// Not that since Rust strings are assumed to be in UTF-8 encoding, this method is equivalent to `new_utf8`.
     ///
     /// # Examples
     ///
@@ -33,7 +34,7 @@ impl RString {
     /// str == 'Hello, World!'
     /// ```
     pub fn new(string: &str) -> Self {
-        Self::from(string::new(string))
+        Self::new_utf8(string)
     }
 
     /// Creates a new instance of Ruby `String`, with UTF8 encoding, containing
@@ -61,6 +62,31 @@ impl RString {
         Self::from(string::new_utf8(string))
     }
 
+    /// Creates a new instance of Ruby `String` containing given `string`.
+    /// This method forces the string's encoding to ASCII-8bit.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use ruru::{RString, VM};
+    /// # VM::init();
+    ///
+    /// let string = RString::new_ascii("Hello, World!");
+    ///
+    /// assert_eq!(string.to_str(), "Hello, World!");
+    /// ```
+    ///
+    /// Ruby:
+    ///
+    /// ```ruby
+    /// str = 'Hello, World!'
+    ///
+    /// str == 'Hello, World!'
+    /// ```
+    pub fn new_ascii(string: &str) -> Self {
+        Self::from(string::new(string))
+    }
+
     /// Retrieves underlying Rust `String` from Ruby `String` object.
     ///
     /// # Examples