From 981b5c08d07e01e6a0f4c7f59c36045e97055cc2 Mon Sep 17 00:00:00 2001
From: Greg Shuflin <greg.shuflin@protonmail.com>
Date: Sun, 16 Oct 2022 00:54:41 -0700
Subject: [PATCH] Make map a method

---
 src/lib.rs | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 602ce57..16da3dd 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -6,16 +6,28 @@ type ParseResult<I, O, E> = Result<(O, I), E>;
 
 trait Parser<I, O, E> {
     fn parse(&self, input: I) -> ParseResult<I, O, E>;
+
+    fn map<'a, F, O2>(self, map_fn: F) -> BoxedParser<'a, I, O2, E>
+    where
+        Self: Sized + 'a,
+        I: 'a,
+        E: 'a,
+        O: 'a,
+        O2: 'a,
+        F: Fn(O) -> O2 + 'a,
+    {
+        BoxedParser::new(map(self, map_fn))
+    }
 }
 
-struct BoxedParser<I, O, E> {
-    inner: Box<dyn Parser<I, O, E>>,
+struct BoxedParser<'a, I, O, E> {
+    inner: Box<dyn Parser<I, O, E> + 'a>,
 }
 
-impl<I, O, E> BoxedParser<I, O, E> {
+impl<'a, I, O, E> BoxedParser<'a, I, O, E> {
     fn new<P>(inner: P) -> Self
     where
-        P: Parser<I, O, E> + 'static,
+        P: Parser<I, O, E> + 'a,
     {
         BoxedParser {
             inner: Box::new(inner),
@@ -23,7 +35,7 @@ impl<I, O, E> BoxedParser<I, O, E> {
     }
 }
 
-impl<I, O, E> Parser<I, O, E> for BoxedParser<I, O, E> {
+impl<'a, I, O, E> Parser<I, O, E> for BoxedParser<'a, I, O, E> {
     fn parse(&self, input: I) -> ParseResult<I, O, E> {
         self.inner.parse(input)
     }
@@ -178,7 +190,7 @@ mod tests {
     #[test]
     fn test_map() {
         let lit_a = literal("a");
-        let output = map(lit_a, |s| s.to_uppercase()).parse("a yolo");
+        let output = lit_a.map(|s| s.to_uppercase()).parse("a yolo");
         assert_matches!(output.unwrap(), (s, " yolo") if s == "A");
     }