wip work for join

Author: erkkikeranen

src/clojure_string.rs

@@ -1 +1,2 @@
 pub (crate) mod reverse;
+pub (crate) mod join;

src/clojure_string/join.rs

@@ -0,0 +1,48 @@
+use crate::ifn::IFn;
+use crate::value::{ToValue, Value};
+use std::rc::Rc;
+
+use crate::error_message;
+use crate::type_tag::TypeTag;
+
+/// clojure.string/reverse ; reverses a string
+/// (defn print-string [string] .. prints single string .. )
+#[derive(Debug, Clone)]
+pub struct JoinFn {}
+impl ToValue for JoinFn {
+    fn to_value(&self) -> Value {
+        Value::IFn(Rc::new(self.clone()))
+    }
+}
+impl IFn for JoinFn {
+    fn invoke(&self, args: Vec<Rc<Value>>) -> Value {
+        if args.len() == 1 {
+            match args.get(0).unwrap().to_value() {
+                Value::Iseq(s) => Value::String(s.chars().rev().collect()),
+                _a => error_message::type_mismatch(TypeTag::String, &_a.to_value())
+            }
+
+        } else {
+            return error_message::wrong_arg_count(2, args.len());
+
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    mod reverse_tests {
+        use crate::value::Value;
+        use std::rc::Rc;
+        use crate::clojure_string::reverse::JoinFn;
+        use crate::ifn::IFn;
+
+        #[test]
+        fn reverse_string() {
+            let reverse = JoinFn {};
+            let s = "hello";
+            let args = vec![Rc::new(Value::String(String::from(s)))];
+            assert_eq!(Value::String(String::from("olleh")), reverse.invoke(args));
+        }
+    }
+}