added missing BString implementation

btypes_primitives/src/main/rust/btypes/src/bstring.rs

 use std::fmt::{Display, Formatter};
 use crate::bobject::BObject;
+use crate::bboolean::BBoolean;
 
 #[derive(Default, Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
 pub struct BString {
@@ -17,3 +18,25 @@ impl Display for BString {
 }
 
 impl BObject for BString {}
+
+impl BString {
+    pub fn new(init: &str) -> BString {
+        return BString { val: String::from(init) }
+    }
+
+    pub fn isString(&self) -> BBoolean {
+        return true;
+    }
+
+    pub fn isNotString(&self) -> BBoolean {
+        return false;
+    }
+
+    pub fn equal(&self, other: &BString) -> BBoolean {
+        return self.eq(other);
+    }
+
+    pub fn unequal(&self, other: &BString) -> BBoolean {
+        return !self.eq(other);
+    }
+}