From b8f63045b235ab07aabde5e8f41213df3ecfb872 Mon Sep 17 00:00:00 2001
From: Piotr Swigon <piotrs@google.com>
Date: Wed, 31 Mar 2021 20:48:56 -0700
Subject: [PATCH] Opens up Arcs code to more directories.

PiperOrigin-RevId: 366175605
---
 java/arcs/core/util/Parser.kt | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/java/arcs/core/util/Parser.kt b/java/arcs/core/util/Parser.kt
index 95b6268a488..eba462be56c 100644
--- a/java/arcs/core/util/Parser.kt
+++ b/java/arcs/core/util/Parser.kt
@@ -394,6 +394,19 @@ class ManyOfParser<T>(val parser: Parser<T>) : Parser<List<T>>() {
   }
 }
 
+/**
+ * A parser providing a name for debugging purposes (traceback) but delegates parsing.
+ */
+class NamedParser<T>(name: String, val parser: Parser<T>) : Parser<T>() {
+
+  init {
+    this.name = name
+  }
+
+  override fun invoke(string: String, pos: SourcePosition) = parser.invoke(string, pos)
+  override fun leftTokens() = parser.leftTokens()
+}
+
 class ParserException(msg: String, cause: Exception) : Exception(msg, cause)
 
 /** A parser which converts the return value of a parser into another value. */
@@ -587,6 +600,9 @@ fun <T> many(parser: Parser<T>) = ManyOfParser(parser)
 /** Helper for [AnyOfParser]. */
 fun <T> any(parsers: List<Parser<T>>) = AnyOfParser(parsers)
 
+/** Helper for [NamedParser] */
+fun <T> Parser<T>.named(name: String) = NamedParser(name, this)
+
 /** Helper for [TransformParser]. */
 fun <T, R> Parser<T>.map(f: (T) -> R) = TransformParser(this, f)