2 files changed, 17 insertions, 0 deletions
diff --git a/src/libutil/args.cc b/src/libutil/args.cc
index 7af2a1bf7..b7baad375 100644
--- a/src/libutil/args.cc
+++ b/src/libutil/args.cc
@@ -178,6 +178,19 @@ Strings argvToStrings(int argc, char * * argv)
     return args;
 }
 
+Strings editorFor(Pos pos)
+{
+    auto editor = getEnv("EDITOR", "cat");
+    auto args = tokenizeString<Strings>(editor);
+    if (pos.line > 0 && (
+        editor.find("emacs") != std::string::npos ||
+        editor.find("nano") != std::string::npos ||
+        editor.find("vim") != std::string::npos))
+        args.push_back(fmt("+%d", pos.line));
+    args.push_back(pos.file);
+    return args;
+}
+
 std::string renderLabels(const Strings & labels)
 {
     std::string res;
diff --git a/src/libutil/args.hh b/src/libutil/args.hh
index ad5fcca39..1e29bd4fa 100644
--- a/src/libutil/args.hh
+++ b/src/libutil/args.hh
@@ -5,6 +5,7 @@
 #include <memory>
 
 #include "util.hh"
+#include "nixexpr.hh"
 
 namespace nix {
 
@@ -190,6 +191,9 @@ public:
 
 Strings argvToStrings(int argc, char * * argv);
 
+/* Helper function to generate args that invoke $EDITOR on filename:lineno */
+Strings editorFor(Pos pos);
+
 /* Helper function for rendering argument labels. */
 std::string renderLabels(const Strings & labels);