Hack: env var for boolean flag

The proper way would be using env = "DELTA_NAVIGATE", but see
https://github.com/clap-rs/clap/issues/1476
https://github.com/TeXitoi/structopt/issues/372

Doing it as in this commit probably has drawbacks, e.g. related to
whether the argument is recorded as having been supplied.

1 files changed, 9 insertions, 0 deletions

diff --git a/src/env.rs b/src/env.rs
index 70811353..dc30ecca 100644
--- a/src/env.rs
+++ b/src/env.rs
@@ -8,3 +8,12 @@ pub fn get_env_var(name: &str) -> Option<String> {
         non_empty_string => Some(non_empty_string.to_string()),
     }
 }
+
+pub fn get_boolean_env_var(name: &str) -> bool {
+    let val = get_env_var(name).map(|s| s.to_lowercase());
+    match val.as_deref() {
+        None => false,
+        Some("false") => false,
+        Some(_) => true,
+    }
+}