:line_up_no_cycle and :line_down_no_cyle

May be mapped instead of :line_up and :line_down when you
don't want to cycle (ie arrive on top when you go down past
the end of the tree/list):

	{
		key: ctrl-u
		internal: line_up_no_cycle
	}
	{
		key: ctrl-j
		internal: line_down_no_cycle
	}

3 files changed, 34 insertions, 2 deletions

diff --git a/src/command/mod.rs b/src/command/mod.rs
index 70e89f5..c42a3cb 100644
--- a/src/command/mod.rs
+++ b/src/command/mod.rs
@@ -3,6 +3,7 @@ mod completion;
 mod panel_input;
 mod parts;
 mod sequence;
+mod sel;
 mod scroll;
 mod trigger_type;
 
@@ -12,6 +13,7 @@ pub use {
     panel_input::PanelInput,
     parts::CommandParts,
     sequence::Sequence,
+    sel::move_sel,
     scroll::ScrollCommand,
     trigger_type::TriggerType,
 };
diff --git a/src/command/panel_input.rs b/src/command/panel_input.rs
index b065730..903bd59 100644
--- a/src/command/panel_input.rs
+++ b/src/command/panel_input.rs
@@ -309,9 +309,9 @@ impl PanelInput {
             }
             Event::Wheel(lines_count) => {
                 let internal = if lines_count > 0 {
-                    Internal::line_down
+                    Internal::line_down_no_cycle
                 } else {
-                    Internal::line_up
+                    Internal::line_up_no_cycle
                 };
                 return Command::Internal {
                     internal,
diff --git a/src/command/sel.rs b/src/command/sel.rs
new file mode 100644
index 0000000..e345bb3
--- /dev/null
+++ b/src/command/sel.rs
@@ -0,0 +1,30 @@
+
+
+/// compute a new selection index for the given list len,
+/// taking into account whether we should cycle or not
+pub fn move_sel(
+    selection: usize,
+    len: usize,
+    d: i32, // displacement
+    cycle: bool,
+) -> usize {
+    if len == 0 {
+        return 0;
+    }
+    let ns = (selection as i32) + d;
+    if ns < 0 {
+        if cycle {
+            len - 1
+        } else {
+            0
+        }
+    } else if ns >= len as i32 {
+        if cycle {
+            0
+        } else {
+            len - 1
+        }
+    } else {
+        ns as usize
+    }
+}