partway towards commands

I got very confused and started mucking about with "spawn" when in fact all I needed was the "inline" extension type in orcx that allows the interpreter to expose custom constants.

orchid-base/src/iter_print.rs

@@ -0,0 +1,26 @@
+use std::fmt;
+
+use itertools::{Itertools, Position};
+
+pub struct PrintList<'a, I: Iterator<Item = E> + Clone, E: fmt::Display>(pub I, pub &'a str);
+impl<'a, I: Iterator<Item = E> + Clone, E: fmt::Display> fmt::Display for PrintList<'a, I, E> {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		for (pos, item) in self.0.clone().with_position() {
+			match pos {
+				Position::First | Position::Only => write!(f, "{item}")?,
+				Position::Middle => write!(f, ", {item}")?,
+				Position::Last => write!(f, ", {} {item}", self.1)?,
+			}
+		}
+		Ok(())
+	}
+}
+
+pub trait IteratorPrint: Iterator<Item: fmt::Display> + Clone {
+	/// Pretty-print a list with a comma-separated enumeration and an operator
+	/// word (such as "and" or "or") inserted before the last
+	fn display<'a>(self, operator: &'a str) -> PrintList<'a, Self, Self::Item> {
+		PrintList(self, operator)
+	}
+}
+impl<T: Iterator<Item: fmt::Display> + Clone> IteratorPrint for T {}