Check the DIALOG environment variable in default_backend

This patch changes the logic in default_backend to respect the DIALOG
environment variable that may contain the name of the backend to use.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/backends/mod.rs b/src/backends/mod.rs
index b9cecd0..20cb8c1 100644
--- a/src/backends/mod.rs
+++ b/src/backends/mod.rs
@@ -31,3 +31,11 @@ pub trait Backend {
     /// Shows the given question dialog and returns the choice.
     fn show_question(&self, question: &super::Question) -> Result<super::Choice>;
 }
+
+pub(crate) fn from_str(s: &str) -> Option<Box<dyn Backend>> {
+    match s.to_lowercase().as_ref() {
+        "dialog" => Some(Box::new(Dialog::new())),
+        "zenity" => Some(Box::new(Zenity::new())),
+        _ => None,
+    }
+}