From 00d866f2a1d647d66e78f4fdc5e5d99c1cb9da21 Mon Sep 17 00:00:00 2001
From: Greg Shuflin <greg.shuflin@protonmail.com>
Date: Sun, 16 Oct 2022 01:10:48 -0700
Subject: [PATCH] then method

---
 src/lib.rs | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/lib.rs b/src/lib.rs
index 16da3dd..b523613 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -18,6 +18,18 @@ trait Parser<I, O, E> {
     {
         BoxedParser::new(map(self, map_fn))
     }
+
+    fn then<'a, P, O2>(self, next_parser: P) -> BoxedParser<'a, I, (O, O2), E>
+    where
+        Self: Sized + 'a,
+        I: 'a,
+        O: 'a,
+        O2: 'a,
+        E: 'a,
+        P: Parser<I, O2, E> + 'a,
+    {
+        BoxedParser::new(seq(self, next_parser))
+    }
 }
 
 struct BoxedParser<'a, I, O, E> {
@@ -198,6 +210,9 @@ mod tests {
     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]