Implement get and tap functions.

src/parser/parser.rs

@@ -41,6 +41,9 @@ pub enum DustTag<'a> {
     DTHelperLessThan(ParameterizedBlock<'a>),
     DTHelperGreaterThanOrEquals(ParameterizedBlock<'a>),
     DTHelperLessThanOrEquals(ParameterizedBlock<'a>),
+    DTHelperSep(ParameterizedBlock<'a>),
+    DTHelperFirst(ParameterizedBlock<'a>),
+    DTHelperLast(ParameterizedBlock<'a>),
 }
 
 #[derive(Clone, Debug, PartialEq)]
@@ -240,6 +243,18 @@ fn dust_tag(i: &str) -> IResult<&str, DustTag> {
             parameterized_block("{@", &tag_to_path("lt")),
             DustTag::DTHelperLessThan,
         ),
+        map(
+            parameterized_block("{@", &tag_to_path("sep")),
+            DustTag::DTHelperSep,
+        ),
+        map(
+            parameterized_block("{@", &tag_to_path("first")),
+            DustTag::DTHelperFirst,
+        ),
+        map(
+            parameterized_block("{@", &tag_to_path("last")),
+            DustTag::DTHelperLast,
+        ),
     ))(i)
 }