Move seq into separate module

src/lib.rs

@@ -1,6 +1,7 @@
 #![feature(assert_matches)]
 #![allow(dead_code)] //TODO eventually turn this off
 mod bnf;
+mod sequence;
 
 use bnf::Bnf;
 use std::rc::Rc;
@@ -45,7 +46,7 @@ trait Parser<I, O, E> {
         E: 'a,
         P: Parser<I, O2, E> + 'a,
     {
-        BoxedParser::new(seq(self, next_parser))
+        BoxedParser::new(sequence::seq(self, next_parser))
     }
 }
 
@@ -107,20 +108,6 @@ where
     }
 }
 
-fn seq<P1, P2, I, O1, O2, E>(parser1: P1, parser2: P2) -> impl Parser<I, (O1, O2), E>
-where
-    P1: Parser<I, O1, E>,
-    P2: Parser<I, O2, E>,
-{
-    move |input| {
-        parser1.parse(input).and_then(|(result1, rest1)| {
-            parser2
-                .parse(rest1)
-                .map(|(result2, rest2)| ((result1, result2), rest2))
-        })
-    }
-}
-
 fn pred<P, F, I, O>(parser: P, pred_fn: F) -> impl Parser<I, O, I>
 where
     P: Parser<I, O, I>,
@@ -237,15 +224,6 @@ mod tests {
         assert_matches!(output.unwrap(), (s, " yolo") if s == "A");
     }
 
-    #[test]
-    fn test_seq() {
-        let p = seq(identifier, seq(literal(" "), literal("ruts")));
-        assert_matches!(p.parse("fort1 ruts"), Ok((r, "")) if r.0 == "fort1" && r.1 == (" ", "ruts") );
-
-        let p = identifier.then(literal(" ")).then(literal("ruts"));
-        assert_matches!(p.parse("fort1 ruts"), Ok((r, "")) if r.0.0 == "fort1" && r.0.1== " " && r.1 == "ruts");
-    }
-
     #[test]
     fn test_one_or_more() {
         let p = one_or_more(literal("bongo "));

src/sequence.rs

@@ -0,0 +1,31 @@
+use crate::Parser;
+
+pub(crate) fn seq<P1, P2, I, O1, O2, E>(parser1: P1, parser2: P2) -> impl Parser<I, (O1, O2), E>
+where
+    P1: Parser<I, O1, E>,
+    P2: Parser<I, O2, E>,
+{
+    move |input| {
+        parser1.parse(input).and_then(|(result1, rest1)| {
+            parser2
+                .parse(rest1)
+                .map(|(result2, rest2)| ((result1, result2), rest2))
+        })
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use crate::{identifier, literal};
+    use std::assert_matches::assert_matches;
+
+    #[test]
+    fn test_seq() {
+        let p = seq(identifier, seq(literal(" "), literal("ruts")));
+        assert_matches!(p.parse("fort1 ruts"), Ok((r, "")) if r.0 == "fort1" && r.1 == (" ", "ruts") );
+
+        let p = identifier.then(literal(" ")).then(literal("ruts"));
+        assert_matches!(p.parse("fort1 ruts"), Ok((r, "")) if r.0.0 == "fort1" && r.0.1== " " && r.1 == "ruts");
+    }
+}