Preparation for sharing

- rustfmt
- clippy
- comments
- README

src/external/cpsio/print.rs

@@ -1,43 +1,40 @@
 use std::fmt::Debug;
 
+use super::io::IO;
 use crate::external::litconv::with_str;
 use crate::foreign::{Atomic, AtomicResult, AtomicReturn};
 use crate::interpreter::Context;
-use crate::{atomic_impl, atomic_redirect, externfn_impl, atomic_defaults};
 use crate::representations::interpreted::ExprInst;
+use crate::{atomic_defaults, atomic_impl, atomic_redirect, externfn_impl};
 
-use super::io::IO;
-
-/// Print function
-/// 
+/// Wrap a string and the continuation into an [IO] event to be evaluated by the
+/// embedder.
+///
 /// Next state: [Print1]
-
 #[derive(Clone)]
 pub struct Print2;
-externfn_impl!(Print2, |_: &Self, x: ExprInst| Ok(Print1{x}));
+externfn_impl!(Print2, |_: &Self, x: ExprInst| Ok(Print1 { x }));
 
-/// Partially applied Print function
-/// 
 /// Prev state: [Print2]; Next state: [Print0]
-
 #[derive(Debug, Clone)]
-pub struct Print1{ x: ExprInst }
+pub struct Print1 {
+  x: ExprInst,
+}
 atomic_redirect!(Print1, x);
 atomic_impl!(Print1);
 externfn_impl!(Print1, |this: &Self, x: ExprInst| {
-  with_str(&this.x, |s| {
-    Ok(Print0{ s: s.clone(), x })
-  })
+  with_str(&this.x, |s| Ok(Print0 { s: s.clone(), x }))
 });
 
+/// Prev state: [Print1]
 #[derive(Debug, Clone)]
-pub struct Print0{ s: String, x: ExprInst }
+pub struct Print0 {
+  s: String,
+  x: ExprInst,
+}
 impl Atomic for Print0 {
   atomic_defaults!();
   fn run(&self, ctx: Context) -> AtomicResult {
-    Ok(AtomicReturn::from_data(
-      IO::Print(self.s.clone(), self.x.clone()),
-      ctx
-    ))
+    Ok(AtomicReturn::from_data(IO::Print(self.s.clone(), self.x.clone()), ctx))
   }
-}
+}