allow parenthesesed identifier (reference) as an object key

hcl2/hcl2.lark

@@ -39,6 +39,7 @@ LPAR : "("
 RPAR : ")"
 COMMA : ","
 DOT : "."
+COLON : ":"
 
 expr_term : LPAR new_line_or_comment? expression new_line_or_comment? RPAR
             | float_lit
@@ -74,7 +75,7 @@ EQ : /[ \t]*=(?!=|>)/
 
 tuple : "[" (new_line_or_comment* expression new_line_or_comment* ",")* (new_line_or_comment* expression)? new_line_or_comment* "]"
 object : "{" new_line_or_comment? (new_line_or_comment* (object_elem | (object_elem COMMA)) new_line_or_comment*)* "}"
-object_elem : object_elem_key ( EQ | ":") expression
+object_elem : LPAR? object_elem_key RPAR? ( EQ | COLON ) expression
 object_elem_key : float_lit | int_lit | identifier | STRING_LIT | object_elem_key_dot_accessor
 object_elem_key_dot_accessor : identifier (DOT identifier)+
 

hcl2/reconstructor.py

@@ -395,6 +395,12 @@ def _is_string_wrapped_tf(interp_s: str) -> bool:
 
         return True
 
+    @classmethod
+    def _unwrap_interpolation(cls, value: str) -> str:
+        if cls._is_string_wrapped_tf(value):
+            return value[2:-1]
+        return value
+
     def _newline(self, level: int, count: int = 1) -> Tree:
         return Tree(
             Token("RULE", "new_line_or_comment"),
@@ -560,6 +566,7 @@ def _transform_value_to_expr_term(self, value, level) -> Union[Token, Tree]:
                     continue
 
                 value_expr_term = self._transform_value_to_expr_term(dict_v, level + 1)
+                k = self._unwrap_interpolation(k)
                 elements.append(
                     Tree(
                         Token("RULE", "object_elem"),

hcl2/transformer.py

@@ -98,11 +98,14 @@ def tuple(self, args: List) -> List:
     def object_elem(self, args: List) -> Dict:
         # This returns a dict with a single key/value pair to make it easier to merge these
         # into a bigger dict that is returned by the "object" function
-        key = self.strip_quotes(str(args[0].children[0]))
-        if len(args) == 3:
-            value = args[2]
+        if args[0] == Token("LPAR", "("):
+            key = self.strip_quotes(str(args[1].children[0]))
+            key = f"({key})"
+            key = self.to_string_dollar(key)
+            value = args[4]
         else:
-            value = args[1]
+            key = self.strip_quotes(str(args[0].children[0]))
+            value = args[2]
 
         value = self.to_string_dollar(value)
         return {key: value}

test/helpers/terraform-config-json/variables.json

@@ -46,7 +46,8 @@
     {
       "foo": "${var.account}_bar",
       "bar": {
-        "baz": 1
+        "baz": 1,
+        "${(var.account)}": 2
       }
     },
     {

test/helpers/terraform-config/variables.tf

@@ -8,6 +8,7 @@ locals {
   foo = "${var.account}_bar"
   bar = {
     baz : 1
+    (var.account) : 2
   }
 }