diff --git a/Program.cs b/Program.cs
index a5c2c31..e7acf23 100644
--- a/Program.cs
+++ b/Program.cs
@@ -92,6 +92,7 @@ public enum TokenType
 	Colon,
 	Tick,
 	Backtick,
+	At,
 	Comma,
 	Period,
 	Equal,
@@ -277,6 +278,7 @@ class Scanner
 			case ':': addToken(TokenType.Colon); break;
 			case '\'': addToken(TokenType.Tick); break;
 			case '`': addToken(TokenType.Backtick); break;
+			case '@': addToken(TokenType.At); break;
 			case ',': addToken(TokenType.Comma); break;
 			case '.': addToken(TokenType.Period); break;
 			case '*': addToken(TokenType.Asterisk); break;
diff --git a/grammar.txt b/grammar.txt
index 7313f60..ac1dce0 100644
--- a/grammar.txt
+++ b/grammar.txt
@@ -1,6 +1,6 @@
 expression ->
 	| literal
-//	| IDENTIFIER
+//	| identifier
 //	| sequence
 	| unary
 	| binary
@@ -15,18 +15,19 @@ expression ->
 	| grouping ;
 
 literal -> NUMBER | STRING ;
+identifier -> IDENTIFIER | "@" STRING ;
 grouping -> "(" expression ")" ;
 unary -> ( "-" | "!" ) expression ;
 binary -> expression operator expression ;
 operator ->
 	| "==" | "!=" | "<" | "<=" | ">" | ">="
 	| "+" | "-" | "*" | "/"
-	| "|>" | "<|" | ">>" | "<<"
+//	| "|>" | "<|" | ">>" | "<<"
 	| "++" ;
 if -> "if" expression "then" expression "else" expression ;
-variant -> "`" IDENTIFIER ( "(" ( expression ( "," expression)* )? ")" )? ;
+variant -> "`" identifier ( "(" ( expression ( "," expression)* )? ")" )? ;
 record ->
-	"{" ( IDENTIFIER "=" expression ( "," IDENTIFIER "=" expression )* )? "}" ;
+	"{" ( identifier "=" expression ( "," identifier "=" expression )* )? "}" ;
 list -> "[" ( expression ( "," expression )* )? "]" ;
 field -> expression "." identifier ;
 index -> expression "[" expression "]" ;
diff --git a/strawman4.txt b/strawman4.txt
index 6b0ec27..2683fff 100644
--- a/strawman4.txt
+++ b/strawman4.txt
@@ -2,6 +2,7 @@
 # Moved type annotations into bindings.
 # Added def keyword for top-level bindings.
 # Added and keyword to multiple-binding let-expressions.
+# Added arbitrary strings as identifiers.
 
 # v3
 # Added type aliases.
@@ -37,7 +38,7 @@ def binary_tree(compare: fn('a) -> 'a) -> {
 	empty: tree 'a,
 	insert: fn(tree 'a, 'a) -> tree 'a,
 	find: fn(tree 'a, 'a) -> maybe 'a,
-	func_we_dont_care_about: fn() -> unit
+	@"func we don't care about": fn() -> unit
 } =
 	# A let expression can bind multiple names. Functions have access to all names within the expression,
 	# while other values only have access to names bound before them.
@@ -60,22 +61,22 @@ def binary_tree(compare: fn('a) -> 'a) -> {
 				`eq => `some(value)
 				`lt => find(left, needle)
 				`gt => find(right, needle)
-	and func_we_dont_care_about() = print("ignore me")
-	in {empty, insert, find, func_we_dont_care_about}
+	and @"func we don't care about"() = print("ignore me")
+	in {empty, insert, find, @"func we don't care about"}
 
 # Prints "`some(2)".
 def do_tree_things() =
 	# Assume that int_compare is in the stdlib or something.
-	let {insert, empty, find | stuff_we_dont_need} = binary_tree(int_compare)
+	let {insert, empty, find | @"stuff we don't need"} = binary_tree(int_compare)
 	# I invented this fancy partial-application syntax with _, and then found
 	# that Scala does it the same way. Also note the pipe operator from Elm.
 	in
 		empty |> insert(_, 5) |> insert(_, 2) |> insert(_, 10)
 			|> find(2) |> print;
-		stuff_we_dont_need
+		@"stuff we don't need"
 
 # Prints "`some(2)\nignore me".
-def main() = do_tree_things().func_we_dont_care_about()
+def main() = do_tree_things().@"func we don't care about"()
 
 def annotate(note: 'a, obj: {|'b}) -> {note: 'a | 'b} =
 	{ note | obj }