From ab041291fb1d806fc1e9c09ecac4a931289bd38f Mon Sep 17 00:00:00 2001
From: Nick Alexander <nalexander@mozilla.com>
Date: Tue, 17 Jan 2017 11:26:45 -0800
Subject: [PATCH] edn: Bound values by optional whitespace; treat comma as
 whitespace.

---
 edn/src/edn.rustpeg | 21 +++++++++++++--------
 edn/tests/tests.rs  | 41 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 8 deletions(-)

diff --git a/edn/src/edn.rustpeg b/edn/src/edn.rustpeg
index 6de00f05..6ab5df2c 100644
--- a/edn/src/edn.rustpeg
+++ b/edn/src/edn.rustpeg
@@ -104,26 +104,26 @@ keyword -> Value
     }
 
 #[export]
-list -> Value = "(" __ v:(__ value)* __ ")" {
+list -> Value = "(" v:(value)* ")" {
     Value::List(LinkedList::from_iter(v))
 }
 
 #[export]
-vector -> Value = "[" __ v:(__ value)* __ "]" {
+vector -> Value = "[" v:(value)* "]" {
     Value::Vector(v)
 }
 
 #[export]
-set -> Value = "#{" __ v:(__ value)* __ "}" {
+set -> Value = "#{" v:(value)* "}" {
     Value::Set(BTreeSet::from_iter(v))
 }
 
-pair -> (Value, Value) = k:(value) " " v:(value) ", "? {
+pair -> (Value, Value) = k:(value) v:(value) {
     (k, v)
 }
 
 #[export]
-map -> Value = "{" __ v:(pair)* __ "}" {
+map -> Value = "{" v:(pair)* "}" {
     Value::Map(BTreeMap::from_iter(v))
 }
 
@@ -131,11 +131,16 @@ map -> Value = "{" __ v:(pair)* __ "}" {
 // floats are integers and fails to parse
 #[export]
 value -> Value
-    = nil / boolean / float / bigint / integer / text /
+    = __ v:(nil / boolean / float / bigint / integer / text /
       keyword / symbol /
-      list / vector / map / set
+      list / vector / map / set) __ {
+    v
+}
+
+// Clojure (and thus EDN) regards commas as whitespace, and thus the two-element vectors [1 2] and
+// [1,,,,2] are equivalent, as are the maps {:a 1, :b 2} and {:a 1 :b 2}.
+whitespace = (" " / "\r" / "\n" / "\t" / ",")
 
-whitespace = (" " / "\r" / "\n" / "\t")
 comment = ";" [^\r\n]* ("\r" / "\n")?
 
 __ = (whitespace / comment)*
diff --git a/edn/tests/tests.rs b/edn/tests/tests.rs
index a8cbb918..ade8c7b1 100644
--- a/edn/tests/tests.rs
+++ b/edn/tests/tests.rs
@@ -809,6 +809,47 @@ fn test_comments() {
     assert_eq!(value(";\n0"), result);
     assert_eq!(value(";\r0"), result);
 }
+
+#[test]
+fn test_whitespace() {
+    let result = Ok(Value::Vector(vec![Value::Integer(1)]));
+    assert_eq!(value(" [1]"), result);
+    assert_eq!(value("[1] "), result);
+    assert_eq!(value(" [ 1 ] "), result);
+}
+
+#[test]
+fn test_inner_whitespace() {
+    let result = Ok(Value::Vector(vec![Value::Vector(vec![Value::Integer(1)])]));
+    assert_eq!(value("[ [1]]"), result);
+    assert_eq!(value("[ [1] ]"), result);
+    assert_eq!(value("[[1] ]"), result);
+}
+
+#[test]
+fn test_commas() {
+    let result = Ok(Value::Vector(vec![Value::Integer(1), Value::Integer(2)]));
+    assert_eq!(value("[1,2]"), result);
+    assert_eq!(value("[1 ,2]"), result);
+    assert_eq!(value("[1 , 2]"), result);
+    assert_eq!(value("[1 ,2]"), result);
+    assert_eq!(value("[ 1,2]"), result);
+    assert_eq!(value("[1,2 ]"), result);
+}
+
+#[test]
+fn test_spurious_commas() {
+    let result = Ok(Value::Vector(vec![Value::Integer(3)]));
+    assert_eq!(value("[3,]"), result);
+    assert_eq!(value("[3 ,]"), result);
+    assert_eq!(value("[3 , ]"), result);
+    assert_eq!(value("[3, ]"), result);
+    assert_eq!(value("[,3]"), result);
+    assert_eq!(value("[,,3]"), result);
+    assert_eq!(value("[,3,]"), result);
+    assert_eq!(value("[3,,]"), result);
+}
+
 /*
 // Handy templates for creating test cases follow: