1 files changed, 37 insertions, 1 deletions

diff --git a/src/libcmd/installables.cc b/src/libcmd/installables.cc
index 59162c4df..b78581a7c 100644
--- a/src/libcmd/installables.cc
+++ b/src/libcmd/installables.cc
@@ -436,6 +436,26 @@ struct InstallableStorePath : Installable
     }
 };
 
+struct InstallableIndexedStorePath : Installable
+{
+    ref<Store> store;
+    DerivedPath::Built req;
+
+    InstallableIndexedStorePath(ref<Store> store, DerivedPath::Built && req)
+        : store(store), req(std::move(req))
+    { }
+
+    std::string what() const override
+    {
+        return req.to_string(*store);
+    }
+
+    DerivedPaths toDerivedPaths() override
+    {
+        return { req };
+    }
+};
+
 DerivedPaths InstallableValue::toDerivedPaths()
 {
     DerivedPaths res;
@@ -796,7 +816,23 @@ std::vector<std::shared_ptr<Installable>> SourceExprCommand::parseInstallables(
         for (auto & s : ss) {
             std::exception_ptr ex;
 
-            if (s.find('/') != std::string::npos) {
+            auto found = s.rfind('^');
+            if (found != std::string::npos) {
+                try {
+                    result.push_back(std::make_shared<InstallableIndexedStorePath>(
+                        store,
+                        DerivedPath::Built::parse(*store, s.substr(0, found), s.substr(found + 1))));
+                    settings.requireExperimentalFeature(Xp::ComputedDerivations);
+                    continue;
+                } catch (BadStorePath &) {
+                } catch (...) {
+                    if (!ex)
+                        ex = std::current_exception();
+                }
+            }
+
+            found = s.find('/');
+            if (found != std::string::npos) {
                 try {
                     result.push_back(std::make_shared<InstallableStorePath>(store, store->followLinksToStorePath(s)));
                     continue;