add height method to Host trait, and implementors (#3064)

crates/nu-engine/src/env/basic_host.rs

@@ -74,4 +74,9 @@ impl Host for BasicHost {
         term_width -= 1;
         term_width
     }
+
+    fn height(&self) -> usize {
+        let (_, term_height) = term_size::dimensions().unwrap_or((80, 20));
+        term_height
+    }
 }

crates/nu-engine/src/env/host.rs

@@ -15,6 +15,7 @@ pub trait Host: Debug + Send {
     fn env_rm(&mut self, k: OsString);
 
     fn width(&self) -> usize;
+    fn height(&self) -> usize;
 }
 
 impl Host for Box<dyn Host> {
@@ -53,6 +54,10 @@ impl Host for Box<dyn Host> {
     fn width(&self) -> usize {
         (**self).width()
     }
+
+    fn height(&self) -> usize {
+        (**self).height()
+    }
 }
 
 #[derive(Debug)]
@@ -124,4 +129,8 @@ impl Host for FakeHost {
     fn width(&self) -> usize {
         1
     }
+
+    fn height(&self) -> usize {
+        1
+    }
 }