libexpr: findDerivationFilename return Pos instead of tuple

src/libexpr/attr-path.cc

@@ -93,7 +93,7 @@ Value * findAlongAttrPath(EvalState & state, const string & attrPath,
 }
 
 
-std::tuple<std::string, int> findDerivationFilename(EvalState & state, Value & v, std::string what)
+Pos findDerivationFilename(EvalState & state, Value & v, std::string what)
 {
     Value * v2;
     try {
@@ -110,14 +110,16 @@ std::tuple<std::string, int> findDerivationFilename(EvalState & state, Value & v
         throw Error("cannot parse meta.position attribute '%s'", pos);
 
     std::string filename(pos, 0, colon);
-    int lineno;
+    unsigned int lineno;
     try {
         lineno = std::stoi(std::string(pos, colon + 1));
     } catch (std::invalid_argument & e) {
         throw Error("cannot parse line number '%s'", pos);
     }
 
-    return std::make_tuple(filename, lineno);
+    Symbol file = state.symbols.create(filename);
+
+    return { file, lineno, 0 };
 }
 
 

src/libexpr/attr-path.hh

@@ -4,15 +4,13 @@
 
 #include <string>
 #include <map>
-#include <tuple>
 
 namespace nix {
 
 Value * findAlongAttrPath(EvalState & state, const string & attrPath,
     Bindings & autoArgs, Value & vIn);
 
-/* Heuristic to find the filename and lineno or a derivation. */
-std::tuple<std::string, int> findDerivationFilename(EvalState & state,
-    Value & v, std::string what);
+/* Heuristic to find the filename and lineno or a nix value. */
+Pos findDerivationFilename(EvalState & state, Value & v, std::string what);
 
 }

src/nix/edit.cc

@@ -36,9 +36,9 @@ struct CmdEdit : InstallableCommand
 
         auto v = installable->toValue(*state);
 
-        std::string filename;
-        int lineno;
-        std::tie(filename, lineno) = findDerivationFilename(*state, *v, installable->what());
+        Pos pos = findDerivationFilename(*state, *v, installable->what());
+        std::string filename(pos.file);
+        int lineno(pos.line);
 
         stopProgressBar();
 

src/nix/repl.cc

@@ -481,7 +481,9 @@ bool NixRepl::processLine(string line)
             lineno = 0;
         } else {
             // assume it's a derivation
-            std::tie(filename, lineno) = findDerivationFilename(state, v, arg);
+            Pos pos = findDerivationFilename(state, v, arg);
+            filename = pos.file;
+            lineno = pos.line;
         }
 
         // Open in EDITOR