From 329effe4ead92616ce090d1583a3de8da3b44758 Mon Sep 17 00:00:00 2001
From: Richard Feldman <oss@rtfeldman.com>
Date: Tue, 3 Sep 2019 22:38:05 -0400
Subject: [PATCH] Add one_of2 and one_of3

---
 src/parse/parser.rs | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/src/parse/parser.rs b/src/parse/parser.rs
index 088f5063f3..b8198ddb47 100644
--- a/src/parse/parser.rs
+++ b/src/parse/parser.rs
@@ -252,3 +252,38 @@ fn whitespace<'a>() -> impl Parser<'a, char> {
     // TODO advance the state appropriately, in terms of line, col, indenting, etc.
     satisfies(any, |ch| ch.is_whitespace())
 }
+
+pub fn one_of2<'a, P1, P2, A>(p1: P1, p2: P2) -> impl Parser<'a, A>
+where
+    P1: Parser<'a, A>,
+    P2: Parser<'a, A>,
+{
+    move |arena: &'a Bump, state: State<'a>, attempting| {
+        if let Ok((next_state, output)) = p1.parse(arena, state, attempting) {
+            Ok((next_state, output))
+        } else if let Ok((next_state, output)) = p2.parse(arena, state, attempting) {
+            Ok((next_state, output))
+        } else {
+            Err((state.clone(), attempting))
+        }
+    }
+}
+
+pub fn one_of3<'a, P1, P2, P3, A>(p1: P1, p2: P2, p3: P3) -> impl Parser<'a, A>
+where
+    P1: Parser<'a, A>,
+    P2: Parser<'a, A>,
+    P3: Parser<'a, A>,
+{
+    move |arena: &'a Bump, state: State<'a>, attempting| {
+        if let Ok((next_state, output)) = p1.parse(arena, state, attempting) {
+            Ok((next_state, output))
+        } else if let Ok((next_state, output)) = p2.parse(arena, state, attempting) {
+            Ok((next_state, output))
+        } else if let Ok((next_state, output)) = p3.parse(arena, state, attempting) {
+            Ok((next_state, output))
+        } else {
+            Err((state.clone(), attempting))
+        }
+    }
+}