simplify checks and update prompts

Author: cvanelteren

libmamba/src/core/activation.cpp

@@ -1248,32 +1248,32 @@ namespace mamba
 
         if (!env_transform.export_path.empty())
         {
-            out << "PATH = " << env_transform.export_path << (util::on_win ? ';' : ':');
+            out << "PATH = " << env_transform.export_path << "\n";
         }
 
         for (const fs::u8path& ds : env_transform.deactivate_scripts)
         {
-            out << "source " << ds << ";";
+            out << "source " << ds << "\n";
         }
 
         for (const std::string& uvar : env_transform.unset_vars)
         {
-            out << "hide-env " << uvar << ";";
+            out << "hide-env " << uvar << "\n";
         }
 
         for (const auto& [skey, svar] : env_transform.set_vars)
         {
-            out << "let " << skey << " = " << svar << ";";
+            out << "let " << skey << " = " << svar << "\n";
         }
 
         for (const auto& [ekey, evar] : env_transform.export_vars)
         {
             // add unix or windows handling
-            out << ekey << " = " << evar << (util::on_win ? ';' : ':');
+            out << ekey << " = " << evar << "\n";
         }
         for (const fs::u8path& p : env_transform.activate_scripts)
         {
-            out << "source " << p << ";";
+            out << "source " << p << "\n";
         }
         return out.str();
     }

libmamba/src/core/shell_init.cpp

@@ -496,14 +496,21 @@ namespace mamba
     }
     #ask mamba how to setup the environment and set the environment
     (^($env.MAMBA_EXE) shell activate --shell nu $name
+      | lines
       | str replace --regex '\s+' '' --all
-      | split row (if $nu.os-info.name == "windows" { ";" } else { ":" })
-      | parse --regex '(.*)=(.+)'
-      | transpose --header-row
-      | into record
+      | parse --regex '([^=]+)=(.+)'
+      | reduce -f {} { |it, acc|
+          $acc | merge {
+              $it.capture0: (
+                  if ($it.capture0 == "PATH") or ($it.capture0 | str ends-with "_PATH") {
+                      $it.capture1 | split row (if $nu.os-info.name == "Windows" { ";" } else { ":" }) | where { |path| $path != "" }
+                  } else {
+                      $it.capture1
+                  }
+              )
+          }
+      }
       | load-env
-    )
-    $env.PATH = $env.PATH | split row (char esep)
     # update prompt
     if ($env.CONDA_PROMPT_MODIFIER? != null) {
       $env.PROMPT_COMMAND = {|| $env.CONDA_PROMPT_MODIFIER + (do $env.PROMPT_COMMAND_BK)}