Simplify and polish pager.rs and related code

src/pager.rs

@@ -1,28 +1,27 @@
+/// If we use a pager, this enum tells us from where we were told to use it.
 #[derive(Debug, PartialEq)]
 pub enum PagerSource {
+    /// From --config
+    Config,
+
     /// From the env var BAT_PAGER
     BatPagerEnvVar,
 
     /// From the env var PAGER
     PagerEnvVar,
 
-    /// From --config
-    Config,
-
     /// No pager was specified, default is used
     Default,
 }
 
+/// A pager such as 'less', and from where we got it.
 pub struct Pager {
     pub pager: String,
     pub source: PagerSource,
 }
 
 impl Pager {
-    fn new(
-        pager: &str,
-        source: PagerSource
-    ) -> Pager {
+    fn new(pager: &str, source: PagerSource) -> Pager {
         Pager {
             pager: String::from(pager),
             source,
@@ -30,16 +29,16 @@ impl Pager {
     }
 }
 
-pub fn get_pager(
-    pager_from_config: Option<&str>,
-) -> Pager {
-    if pager_from_config.is_some() {
-        return Pager::new(pager_from_config.unwrap(), PagerSource::Config);
-    } else {
-        return match (std::env::var("BAT_PAGER"), std::env::var("PAGER")) {
-            (Ok(bat_pager), _) => Pager::new(&bat_pager, PagerSource::BatPagerEnvVar),
-            (_, Ok(pager)) => Pager::new(&pager, PagerSource::PagerEnvVar),
-            _ => Pager::new("less", PagerSource::Default),
-        };
+/// Returns what pager to use, after looking at both config and environment variables.
+pub fn get_pager(pager_from_config: Option<&str>) -> Pager {
+    match (
+        pager_from_config,
+        std::env::var("BAT_PAGER"),
+        std::env::var("PAGER"),
+    ) {
+        (Some(config), _, _) => Pager::new(config, PagerSource::Config),
+        (_, Ok(bat_pager), _) => Pager::new(&bat_pager, PagerSource::BatPagerEnvVar),
+        (_, _, Ok(pager)) => Pager::new(&pager, PagerSource::PagerEnvVar),
+        _ => Pager::new("less", PagerSource::Default),
     }
 }