From 2909cdf296b4079122e21c32cfb9ad5a49c2ae07 Mon Sep 17 00:00:00 2001
From: Greg Shuflin <greg@everydayimshuflin.com>
Date: Mon, 29 Jan 2024 20:14:53 -0800
Subject: [PATCH] named parser

---
 src/parser.rs   | 37 +++++++++++++++++++++++++++++++++++++
 src/test/mod.rs |  6 ++++++
 2 files changed, 43 insertions(+)

diff --git a/src/parser.rs b/src/parser.rs
index 3a79563..1675d63 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -1,9 +1,14 @@
+use std::marker::PhantomData;
+
 use crate::{map, seq2, surrounded_by};
 
 pub type ParseResult<I, O, E> = Result<(O, I), (E, I)>;
 
 pub trait Parser<I, O, E> {
     fn parse(&self, input: I) -> ParseResult<I, O, E>;
+    fn name(&self) -> Option<String> {
+        None
+    }
 }
 
 impl<I, O, E, F> Parser<I, O, E> for F
@@ -15,6 +20,28 @@ where
     }
 }
 
+pub struct NamedParser<P, I, O, E>
+where
+    P: Parser<I, O, E>,
+{
+    inner: P,
+    name: String,
+    phantom: PhantomData<(I, O, E)>,
+}
+
+impl<P, I, O, E> Parser<I, O, E> for NamedParser<P, I, O, E>
+where
+    P: Parser<I, O, E>,
+{
+    fn parse(&self, input: I) -> ParseResult<I, O, E> {
+        self.inner.parse(input)
+    }
+
+    fn name(&self) -> Option<String> {
+        Some(self.name.clone())
+    }
+}
+
 pub trait ParserExtension<I, O, E>: Parser<I, O, E> {
     fn map<F, O2>(self, map_fn: F) -> impl Parser<I, O2, E>
     where
@@ -25,6 +52,16 @@ pub trait ParserExtension<I, O, E>: Parser<I, O, E> {
     fn then_ignore<O2, P: Parser<I, O2, E>>(self, next: P) -> impl Parser<I, O, E>;
     fn ignore_then<O2, P: Parser<I, O2, E>>(self, next: P) -> impl Parser<I, O2, E>;
     fn surrounded_by<O2>(self, surrounding: impl Parser<I, O2, E>) -> impl Parser<I, O, E>;
+    fn to_named(self, name: &str) -> NamedParser<Self, I, O, E>
+    where
+        Self: Sized,
+    {
+        NamedParser {
+            inner: self,
+            name: name.to_string(),
+            phantom: PhantomData,
+        }
+    }
 }
 
 impl<T, I, O, E> ParserExtension<I, O, E> for T
diff --git a/src/test/mod.rs b/src/test/mod.rs
index e0cdbcc..9d5a67f 100644
--- a/src/test/mod.rs
+++ b/src/test/mod.rs
@@ -73,3 +73,9 @@ fn test_repeated() {
     assert_eq!(output.0.len(), 0);
     assert_eq!(output.1, "tra la la");
 }
+
+#[test]
+fn test_named_parser() {
+    let parser = literal("yokel").to_named("yokelparser");
+    assert_eq!(parser.name(), Some("yokelparser".to_string()));
+}