treat $$ as a reserved token that sits on its own line (#29)

src/lib.rs

@@ -1415,4 +1415,23 @@ mod tests {
 
         assert_eq!(format(input, &QueryParams::None, options), expected);
     }
+
+    #[test]
+    fn it_keeps_double_dollar_signs_together() {
+        let input = "CREATE FUNCTION abc() AS $$ SELECT * FROM table $$ LANGUAGE plpgsql;";
+        let options = FormatOptions::default();
+        let expected = indoc!(
+            "
+            CREATE FUNCTION abc() AS
+            $$
+            SELECT
+              *
+            FROM
+              table
+            $$
+            LANGUAGE plpgsql;"
+        );
+
+        assert_eq!(format(input, &QueryParams::None, options), expected);
+    }
 }

src/tokenizer.rs

@@ -533,6 +533,7 @@ fn get_top_level_reserved_token_no_indent(input: &str) -> IResult<&str, Token<'_
         terminated(tag("MINUS"), end_of_word),
         terminated(tag("UNION"), end_of_word),
         terminated(tag("UNION ALL"), end_of_word),
+        terminated(tag("$$"), end_of_word),
     ))(&uc_input);
     if let Ok((_, token)) = result {
         let final_word = token.split(' ').last().unwrap();