1 files changed, 95 insertions, 0 deletions
diff --git a/src/nix/repl.cc b/src/nix/repl.cc
new file mode 100644
index 000000000..679bdea77
--- /dev/null
+++ b/src/nix/repl.cc
@@ -0,0 +1,95 @@
+#include "eval.hh"
+#include "globals.hh"
+#include "command.hh"
+#include "repl.hh"
+
+namespace nix {
+
+struct CmdRepl : InstallablesCommand
+{
+    CmdRepl() {
+        evalSettings.pureEval = false;
+    }
+
+    void prepare() override
+    {
+        if (!settings.isExperimentalFeatureEnabled(Xp::ReplFlake) && !(file) && this->_installables.size() >= 1) {
+            warn("future versions of Nix will require using `--file` to load a file");
+            if (this->_installables.size() > 1)
+                warn("more than one input file is not currently supported");
+            auto filePath = this->_installables[0].data();
+            file = std::optional(filePath);
+            _installables.front() = _installables.back();
+            _installables.pop_back();
+        }
+        installables = InstallablesCommand::load();
+    }
+
+    std::vector<std::string> files;
+
+    Strings getDefaultFlakeAttrPaths() override
+    {
+        return {""};
+    }
+
+    bool useDefaultInstallables() override
+    {
+        return file.has_value() or expr.has_value();
+    }
+
+    bool forceImpureByDefault() override
+    {
+        return true;
+    }
+
+    std::string description() override
+    {
+        return "start an interactive environment for evaluating Nix expressions";
+    }
+
+    std::string doc() override
+    {
+        return
+          #include "repl.md"
+          ;
+    }
+
+    void run(ref<Store> store) override
+    {
+        auto state = getEvalState();
+        auto getValues = [&]()->AbstractNixRepl::AnnotatedValues{
+            auto installables = load();
+            AbstractNixRepl::AnnotatedValues values;
+            for (auto & installable: installables){
+                auto what = installable->what();
+                if (file){
+                    auto [val, pos] = installable->toValue(*state);
+                    auto what = installable->what();
+                    state->forceValue(*val, pos);
+                    auto autoArgs = getAutoArgs(*state);
+                    auto valPost = state->allocValue();
+                    state->autoCallFunction(*autoArgs, *val, *valPost);
+                    state->forceValue(*valPost, pos);
+                    values.push_back( {valPost, what });
+                } else {
+                    auto [val, pos] = installable->toValue(*state);
+                    values.push_back( {val, what} );
+                }
+            }
+            return values;
+        };
+        auto repl = AbstractNixRepl::create(
+            searchPath,
+            openStore(),
+            state,
+            getValues
+        );
+        repl->autoArgs = getAutoArgs(*repl->state);
+        repl->initEnv();
+        repl->mainLoop();
+    }
+};
+
+static auto rCmdRepl = registerCommand<CmdRepl>("repl");
+
+}