From 5640b528349c43717aa501797a4f337373ebf3e4 Mon Sep 17 00:00:00 2001
From: Tom Bereknyei <tomberek@gmail.com>
Date: Fri, 11 Mar 2022 13:26:08 -0500
Subject: [PATCH] repl: use installables

---
 src/libcmd/command.hh      |  2 +-
 src/libcmd/installables.cc | 12 +++++++-----
 src/libcmd/installables.hh |  1 +
 src/nix/repl.cc            | 23 ++++++++++++-----------
 src/nix/repl.md            | 30 +++++++++++++++++++++++++++---
 5 files changed, 48 insertions(+), 20 deletions(-)

diff --git a/src/libcmd/command.hh b/src/libcmd/command.hh
index 65626e33f..65eb0c4a0 100644
--- a/src/libcmd/command.hh
+++ b/src/libcmd/command.hh
@@ -114,6 +114,7 @@ struct InstallablesCommand : virtual Args, SourceExprCommand
     InstallablesCommand();
 
     void prepare() override;
+    Installables load();
 
     virtual bool useDefaultInstallables() { return true; }
 
@@ -132,7 +133,6 @@ struct InstallableCommand : virtual Args, SourceExprCommand
     InstallableCommand(bool supportReadOnlyMode = false);
 
     void prepare() override;
-    std::shared_ptr<Installable> load();
 
     std::optional<FlakeRef> getFlakeRefForCompletion() override
     {
diff --git a/src/libcmd/installables.cc b/src/libcmd/installables.cc
index 7d2ff0f68..c29fbeec9 100644
--- a/src/libcmd/installables.cc
+++ b/src/libcmd/installables.cc
@@ -1025,11 +1025,16 @@ InstallablesCommand::InstallablesCommand()
 
 void InstallablesCommand::prepare()
 {
+    installables = load();
+}
+
+Installables InstallablesCommand::load() {
+    Installables installables;
     if (_installables.empty() && useDefaultInstallables())
         // FIXME: commands like "nix profile install" should not have a
         // default, probably.
         _installables.push_back(".");
-    installables = parseInstallables(getStore(), _installables);
+    return parseInstallables(getStore(), _installables);
 }
 
 std::optional<FlakeRef> InstallablesCommand::getFlakeRefForCompletion()
@@ -1054,13 +1059,10 @@ InstallableCommand::InstallableCommand(bool supportReadOnlyMode)
         }}
     });
 }
-std::shared_ptr<Installable> InstallableCommand::load() {
-    return parseInstallable(getStore(), _installable);
-}
 
 void InstallableCommand::prepare()
 {
-    installable = load();
+    installable = parseInstallable(getStore(), _installable);
 }
 
 }
diff --git a/src/libcmd/installables.hh b/src/libcmd/installables.hh
index 5d715210e..b97888db6 100644
--- a/src/libcmd/installables.hh
+++ b/src/libcmd/installables.hh
@@ -131,6 +131,7 @@ struct Installable
         OperateOn operateOn,
         const std::vector<std::shared_ptr<Installable>> & installables);
 };
+typedef std::vector<std::shared_ptr<Installable>> Installables;
 
 struct InstallableValue : Installable
 {
diff --git a/src/nix/repl.cc b/src/nix/repl.cc
index df921ef06..b5ecc8ad0 100644
--- a/src/nix/repl.cc
+++ b/src/nix/repl.cc
@@ -43,8 +43,6 @@ extern "C" {
 
 namespace nix {
 
-typedef std::vector<std::shared_ptr<Installable>> Installables;
-
 struct NixRepl
     #if HAVE_BOEHMGC
     : gc
@@ -899,17 +897,16 @@ std::ostream & NixRepl::printValue(std::ostream & str, Value & v, unsigned int m
     return str;
 }
 
-struct CmdRepl : InstallableCommand
+struct CmdRepl : InstallablesCommand
 {
     std::vector<std::string> files;
-    Strings getDefaultFlakeAttrPathPrefixes()
-    override {
-        return {};
-    }
     Strings getDefaultFlakeAttrPaths()
     override {
         return {""};
     }
+    virtual bool useDefaultInstallables() {
+        return file.has_value() or expr.has_value();
+    }
 
     CmdRepl()
     {
@@ -934,10 +931,14 @@ struct CmdRepl : InstallableCommand
         auto state = getEvalState();
         auto repl = std::make_unique<NixRepl>(searchPath, openStore(),state
                 ,[&]()->NixRepl::AnnotatedValues{
-                   auto installable = load();
-                   auto [val, pos] = installable->toValue(*state);
-                   auto what = installable->what();
-                   return { {val,what} };
+                   auto installables = load();
+                   NixRepl::AnnotatedValues values;
+                   for (auto & installable: installables){
+                       auto [val, pos] = installable->toValue(*state);
+                       auto what = installable->what();
+                       values.push_back( {val,what} );
+                   }
+                   return values;
                 }
             );
         repl->autoArgs = getAutoArgs(*repl->state);
diff --git a/src/nix/repl.md b/src/nix/repl.md
index 9b6f2bee3..be1498e5b 100644
--- a/src/nix/repl.md
+++ b/src/nix/repl.md
@@ -24,10 +24,34 @@ R""(
 * Interact with Nixpkgs in the REPL:
 
   ```console
-  # nix repl '<nixpkgs>'
+  # nix repl --file example.nix
+  Loading Installable ''...
+  Added 3 variables.
 
-  Loading '<nixpkgs>'...
-  Added 12428 variables.
+  # nix repl --expr '{a={b=3;c=4;};}'
+  Loading Installable ''...
+  Added 1 variables.
+
+  # nix repl --expr '{a={b=3;c=4;};}' a
+  Loading Installable ''...
+  Added 1 variables.
+
+  # nix repl nixpkgs
+  Loading Installable 'flake:nixpkgs#'...
+  Added 5 variables.
+
+  nix-repl> legacyPackages.x86_64-linux.emacs.name
+  "emacs-27.1"
+
+  nix-repl> legacyPackages.x86_64-linux.emacs.name
+  "emacs-27.1"
+
+  nix-repl> :q
+
+  # nix repl --expr 'import <nixpkgs>{}' --impure
+
+  Loading Installable ''...
+  Added 12439 variables.
 
   nix-repl> emacs.name
   "emacs-27.1"