[stdlib-candidate] set-env

stdlib-candidate/set-env.nu

@@ -0,0 +1,37 @@
+# Gracefully set an environment variable or merge a nested option.
+#
+# Examples:
+#   Set $env.NUPM_HOME
+#   > set-env NUPM_HOME $'($nu.home-path)/.local/share/nupm'
+#
+#   Add to $env.NU_LIB_DIRS
+#   > set-env --append NU_LIB_DIRS $'($env.NUPM_HOME)/modules'
+#
+#   Set a nested config option
+#   > set-env config.filesize.metric true
+#
+#   Add a config hook
+#   > set-env -a config.hooks.pre_prompt 'ellie | print'
+export def --env main [
+  field: cell-path # The environment variable name or nested option cell path
+  value: any # The value to set or append
+  --append (-a) # Append to the previous value or wrap in a new list
+]: nothing -> nothing {
+  def 'get or' [default field] {
+    get --ignore-errors $field | default $default
+  }
+  let value = if $append {
+    $env | get or [] $field | append $value
+  } else {
+    $value
+  }
+  let field = $field | to text | split row .
+  let value = match $field {
+    [_] => $value
+    [$root, ..$field] => {
+      let field = $field | into cell-path
+      $env | get or {} $root | upsert $field $value
+    }
+  }
+  load-env { ($field | first): $value }
+}