refine reference type in format_to_lisp; tag 0.1.13

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cirru_parser"
-version = "0.1.12"
+version = "0.1.13"
 authors = ["jiyinyiyong <[email protected]>"]
 edition = "2018"
 license = "MIT"

src/parser.rs

@@ -337,7 +337,7 @@ pub fn parse(code: &str) -> Result<Vec<Cirru>, String> {
 
 pub fn cirru_to_lisp(code: String) -> String {
   match parse(&code) {
-    Ok(tree) => match format_to_lisp(tree) {
+    Ok(tree) => match format_to_lisp(&tree) {
       Ok(s) => s,
       Err(_) => panic!("failed to convert to lisp"),
     },

src/primes.rs

@@ -154,7 +154,7 @@ impl Cirru {
   pub fn to_lisp(&self) -> Result<String, String> {
     match self {
       Cirru::Leaf(_) => Err(format!("expected list to convert to Lisp, got {}", self)),
-      Cirru::List(xs) => s_expr::format_to_lisp(xs.to_owned()),
+      Cirru::List(xs) => s_expr::format_to_lisp(xs),
     }
   }
 

src/s_expr.rs

@@ -1,11 +1,11 @@
 use crate::primes::Cirru;
 
 /// format to Cirru to WAT
-pub fn format_to_lisp(xs: Vec<Cirru>) -> Result<String, String> {
+pub fn format_to_lisp(xs: &[Cirru]) -> Result<String, String> {
   let mut content: String = String::from("\n");
 
   for expr in xs {
-    content = format!("{}{}\n", content, format_expr(&expr, 0)?);
+    content = format!("{}{}\n", content, format_expr(expr, 0)?);
   }
 
   Ok(content)