Preparation for sharing

- rustfmt
- clippy
- comments
- README

src/interpreter/error.rs

@@ -1,8 +1,8 @@
 use std::fmt::Display;
 use std::rc::Rc;
 
-use crate::representations::interpreted::ExprInst;
 use crate::foreign::ExternError;
+use crate::representations::interpreted::ExprInst;
 
 /// Problems in the process of execution
 #[derive(Clone, Debug)]
@@ -21,7 +21,8 @@ impl Display for RuntimeError {
   fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
     match self {
       Self::Extern(e) => write!(f, "Error in external function: {e}"),
-      Self::NonFunctionApplication(loc) => write!(f, "Primitive applied as function at {loc:?}")
+      Self::NonFunctionApplication(loc) =>
+        write!(f, "Primitive applied as function at {loc:?}"),
     }
   }
-}
+}