Fix issue #35

Fix an odd degenerate case where empty list literals aren't displayed.

Author: slott56

src/celpy/celparser.py

@@ -335,6 +335,8 @@ def list_lit(self, tree: lark.Tree) -> None:
         if self.stack:
             left = self.stack.pop()
             self.stack.append(f"[{left}]")
+        else:
+            self.stack.append("")
 
     def map_lit(self, tree: lark.Tree) -> None:
         if self.stack:

tests/test_parser.py

@@ -439,6 +439,12 @@ def test_dump_ast(parser):
     assert DumpAST.display(ast6) == ".min()"
 
 
+def test_dump_issue_35():
+    cel = "[]"
+    tree = CELParser().parse(cel)
+    assert DumpAST.display(tree) == ""
+
+
 def test_tree_dump(parser):
     ast = parser.parse("-(3*4+5-1/2%3==1)?name[index]:f(1,2)||false&&true")
     assert tree_dump(ast) == '- (3 *  4 +  5 -  1 /  2 %  3 ==  1) ? name[index] : f(1, 2) || false && true'