lib/lua: only quote table keys when needed

lib/to-lua.nix

@@ -47,16 +47,18 @@ rec {
           mapAttrsToList (
             n: v:
             let
+              keyString =
+                if n == "__emptyString" then
+                  "['']"
+                else if hasPrefix "__rawKey__" n then
+                  "[${removePrefix "__rawKey__" n}]"
+                else if isIdentifier n then
+                  n
+                else
+                  "[${toLuaObject n}]";
               valueString = toLuaObject v;
             in
-            if hasPrefix "__unkeyed" n then
+            if hasPrefix "__unkeyed" n then valueString else "${keyString} = ${valueString}"
-              valueString
-            else if hasPrefix "__rawKey__" n then
-              ''[${removePrefix "__rawKey__" n}] = '' + valueString
-            else if n == "__emptyString" then
-              "[''] = " + valueString
-            else
-              "[${toLuaObject n}] = " + valueString
           ) (filterAttrs (n: v: v != null && (toLuaObject v != "{}")) args)
         ))
         + "}"

tests/lib-tests.nix

@@ -55,7 +55,7 @@ let
           3
         ];
       };
-      expected = ''{["foo"] = "bar",["qux"] = {1,2,3}}'';
+      expected = ''{foo = "bar",qux = {1,2,3}}'';
     };
 
     testToLuaObjectRawLua = {
@@ -68,7 +68,7 @@ let
         "__unkeyed...." = "foo";
         bar = "baz";
       };
-      expected = ''{"foo",["bar"] = "baz"}'';
+      expected = ''{"foo",bar = "baz"}'';
     };
 
     testToLuaObjectNestedAttrs = {
@@ -81,7 +81,7 @@ let
           };
         };
       };
-      expected = ''{["a"] = {["b"] = 1,["c"] = 2,["d"] = {["e"] = 3}}}'';
+      expected = ''{a = {b = 1,c = 2,d = {e = 3}}}'';
     };
 
     testToLuaObjectNestedList = {
@@ -109,7 +109,7 @@ let
         d = false;
         e = null;
       };
-      expected = ''{["a"] = 1.000000,["b"] = 2,["c"] = true,["d"] = false}'';
+      expected = ''{a = 1.000000,b = 2,c = true,d = false}'';
     };
 
     testToLuaObjectNilPrim = {
@@ -150,7 +150,17 @@ let
           g = helpers.emptyTable;
         };
       };
-      expected = ''{["c"] = { },["d"] = {["g"] = { }}}'';
+      expected = ''{c = { },d = {g = { }}}'';
+    };
+
+    testToLuaObjectQuotedKeys = {
+      expr = helpers.toLuaObject {
+        "1_a" = "a";
+        _b = "b";
+        c = "c";
+        d-d = "d";
+      };
+      expected = ''{["1_a"] = "a",_b = "b",c = "c",["d-d"] = "d"}'';
     };
 
     testIsLuaKeyword = {