From 4171ab4bbd95e9bb4b9d6c6e8c143002d92b0c06 Mon Sep 17 00:00:00 2001
From: Ben Burdette <bburdette@gmail.com>
Date: Tue, 24 Mar 2020 09:18:23 -0600
Subject: [PATCH] renaming

---
 src/libutil/error.cc |  8 +++-----
 src/libutil/error.hh | 31 +++++++++++++++++++++++++++++--
 tests/errors/main.cc |  9 +++++++--
 3 files changed, 39 insertions(+), 9 deletions(-)

diff --git a/src/libutil/error.cc b/src/libutil/error.cc
index 71f422622..81c1f1805 100644
--- a/src/libutil/error.cc
+++ b/src/libutil/error.cc
@@ -41,8 +41,6 @@ void print_code_lines(string &prefix, NixCode &nix_code)
       % nix_code.errLine->errLineOfCode
       << endl;
     
-
-
     // error arrows for the column range.
     if (nix_code.errLine->columnRange.has_value()) 
     {
@@ -98,7 +96,7 @@ void print_error(ErrorInfo &einfo)
       }
   }
 
-  int ndl = level_string.length() + 3 + einfo.errName.length() + einfo.toolName.length();
+  int ndl = level_string.length() + 3 + einfo.name.length() + einfo.program.length();
   int dashwidth = errwidth - 3 ? 3 : 80 - ndl; 
 
   string dashes;
@@ -110,9 +108,9 @@ void print_error(ErrorInfo &einfo)
     % prefix
     % level_string
     % "---"
-    % einfo.errName
+    % einfo.name
     % dashes
-    % einfo.toolName
+    % einfo.program
     << endl;
 
   // filename.
diff --git a/src/libutil/error.hh b/src/libutil/error.hh
index 8dac1508e..69776eb8c 100644
--- a/src/libutil/error.hh
+++ b/src/libutil/error.hh
@@ -39,13 +39,40 @@ class NixCode {
 class ErrorInfo { 
   public:
   ErrLevel level;
-  string errName;
+  string name;
   string description;
-  string toolName;
+  string program;
   optional<NixCode> nixCode;
   string hint;
+  ErrorInfo& GetEI() { return *this; }
 };
 
+template <class T>
+class AddName : private T
+{
+  public:
+    T& name(const std::string &name){
+      GetEI().name = name;
+      return *this;
+    }
+  protected:
+    ErrorInfo& GetEI() { return T::GetEI(); }
+};
+
+template <class T>
+class AddDescription : private T 
+{
+  public:
+    T& description(const std::string &description){
+      GetEI().description = description;
+      return *this;
+    }
+  protected:
+    ErrorInfo& GetEI() { return T::GetEI(); }
+};
+
+typedef AddName<AddDescription<ErrorInfo>> StandardError;
+
 string showErrLine(ErrLine &errLine);
 
 void print_code_lines(string &prefix, NixCode &nix_code); 
diff --git a/tests/errors/main.cc b/tests/errors/main.cc
index 1c998103e..0e6d781c9 100644
--- a/tests/errors/main.cc
+++ b/tests/errors/main.cc
@@ -24,13 +24,18 @@ using namespace nix;
   
   ErrorInfo generic;
   generic.level = elError;
-  generic.errName = "error name";
+  generic.name = "error name";
   generic.description = "general error description";
-  generic.toolName = "nixtool.exe";
+  generic.program = "nixtool.exe";
   generic.nixCode = nixcode;
 
   print_error(generic);
 
+
+  StandardError standardError;
+
+  print_error(standardError.name("blah").description("blah"));
+
   return 0;
 }