list contains implemented

src/run.rs

@@ -120,6 +120,7 @@ pub fn run_callback(ast: &Seg, syms: &mut SymTable) ->  Result<Ctr, String> {
     if let Ok(s) = current_dir() {
         prefixes.push(String::from(s.to_str().unwrap()));
     }
+    prefixes.push(String::from("/"));
     if let Ctr::String(ref filename) = *ast.car {
         for prefix in prefixes {
             let candidate = Path::new(&prefix.clone()).join(filename);

src/stl.rs

@@ -68,13 +68,13 @@ pub fn static_stdlib(syms: &mut SymTable) -> Result<(), String> {
     );
 
     syms.insert(
-        "contains".to_string(),
+        "substr?".to_string(),
         Symbol {
-            name: String::from("contains"),
+            name: String::from("substr?"),
             args: Args::Strict(vec![Type::String, Type::String]),
             conditional_branches: false,
-            docs: strings::CONTAINS_DOCSTRING.to_string(),
-            value: ValueType::Internal(Rc::new(strings::contains_callback)),
+            docs: strings::SUBSTR_DOCSTRING.to_string(),
+            value: ValueType::Internal(Rc::new(strings::substr_callback)),
             ..Default::default()
         },
     );

src/stl/strings.rs

@@ -90,10 +90,10 @@ pub fn strcast_callback(ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String>
     }
 }
 
-pub const CONTAINS_DOCSTRING: &str =
+pub const SUBSTR_DOCSTRING: &str =
     "Takes two strings. Returns true if string1 contains at least one instance of string2";
 
-pub fn contains_callback(ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
+pub fn substr_callback(ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
     let parent_str: String;
     if let Ctr::String(ref s) = *ast.car {
         parent_str = s.to_string();