Working example

src/external/cpsio/print.rs

@@ -0,0 +1,32 @@
+use std::fmt::Debug;
+use std::hash::Hash;
+use std::rc::Rc;
+
+use crate::external::str::cls2str;
+use crate::representations::PathSet;
+use crate::{atomic_impl, atomic_redirect, externfn_impl};
+use crate::representations::interpreted::Clause;
+
+/// Print function
+/// 
+/// Next state: [Print1]
+
+#[derive(Clone)]
+pub struct Print2;
+externfn_impl!(Print2, |_: &Self, c: Clause| {Ok(Print1{c})});
+
+/// Partially applied Print function
+/// 
+/// Prev state: [Print2]; Next state: [Print0]
+
+#[derive(Debug, Clone, PartialEq, Hash)]
+pub struct Print1{ c: Clause }
+atomic_redirect!(Print1, c);
+atomic_impl!(Print1, |Self{ c }: &Self| {
+  let message = cls2str(&c)?;
+  print!("{}", message);
+  Ok(Clause::Lambda {
+    args: Some(PathSet{ steps: Rc::new(vec![]), next: None }),
+    body: Rc::new(Clause::LambdaArg)
+  })
+});