nushell: add envVars attribute (#3930)

modules/programs/nushell.nix

@@ -121,6 +121,15 @@ in {
         this option) to command strings or directly to build outputs.
       '';
     };
+
+    environmentVariables = mkOption {
+      type = types.attrsOf types.str;
+      default = { };
+      example = { FOO = "BAR"; };
+      description = ''
+        An attribute set that maps an environment variable to a shell interpreted string.
+      '';
+    };
   };
 
   config = mkIf cfg.enable {
@@ -141,10 +150,15 @@ in {
         ];
       })
 
-      (mkIf (cfg.envFile != null || cfg.extraEnv != "") {
+      (let
+        envVarsStr = concatStringsSep "\n"
+          (mapAttrsToList (k: v: "let-env ${k} = ${v}")
+            cfg.environmentVariables);
+      in mkIf (cfg.envFile != null || cfg.extraEnv != "" || envVarsStr != "") {
         "${configDir}/env.nu".text = mkMerge [
           (mkIf (cfg.envFile != null) cfg.envFile.text)
           cfg.extraEnv
+          envVarsStr
         ];
       })
     ];

tests/modules/programs/nushell/env-expected.nu

@@ -1,2 +1,4 @@
 let-env FOO = 'BAR'
 
+
+let-env BAR = $'(echo BAZ)'

tests/modules/programs/nushell/example-settings.nix

@@ -20,6 +20,8 @@
       "lsname" = "(ls | get name)";
       "ll" = "ls -a";
     };
+
+    environmentVariables = { BAR = "$'(echo BAZ)'"; };
   };
 
   test.stubs.nushell = { };