args for scroll_{up,down,left,right}; scroll_step_vertical only for mouse

This might break existing custom keybindings, so we mark it BREAKING for
the release notes.

src/keybind/builtin/flow.json

@@ -180,8 +180,8 @@
             ["alt+[", "select_prev_sibling", true],
             ["alt+]", "select_next_sibling", true],
             ["alt+a", "select_all_siblings"],
-            ["alt+shift+home", "move_scroll_left"],
-            ["alt+shift+end", "move_scroll_right"],
+            ["alt+shift+home", "scroll_left"],
+            ["alt+shift+end", "scroll_right"],
             ["alt+shift+up", "add_cursor_up"],
             ["alt+shift+down", "add_cursor_down"],
             ["alt+shift+f12", "goto_type_definition"],

src/tui/editor.zig

@@ -3007,17 +3007,15 @@ pub const Editor = struct {
         self.update_animation_step(dest);
     }
 
-    fn scroll_up(self: *Self) void {
-        const scroll_step_vertical = tui.config().scroll_step_vertical;
+    fn scroll_up_internal(self: *Self, count: usize) void {
         var dest_row = self.scroll_dest;
-        dest_row = if (dest_row > scroll_step_vertical) dest_row - scroll_step_vertical else 0;
+        dest_row -|= count;
         self.update_scroll_dest_abs(dest_row);
     }
 
-    fn scroll_down(self: *Self) void {
-        const scroll_step_vertical = tui.config().scroll_step_vertical;
+    fn scroll_down_internal(self: *Self, count: usize) void {
         var dest_row = self.scroll_dest;
-        dest_row += scroll_step_vertical;
+        dest_row += count;
         self.update_scroll_dest_abs(dest_row);
     }
 
@@ -3040,7 +3038,7 @@ pub const Editor = struct {
         else if (tui.fast_scroll())
             self.scroll_pageup()
         else
-            self.scroll_up();
+            self.scroll_up_internal(tui.config().scroll_step_vertical);
     }
 
     pub fn mouse_scroll_down(self: *Self) void {
@@ -3049,7 +3047,7 @@ pub const Editor = struct {
         else if (tui.fast_scroll())
             self.scroll_pagedown()
         else
-            self.scroll_down();
+            self.scroll_down_internal(tui.config().scroll_step_vertical);
     }
 
     pub fn scroll_to(self: *Self, row: usize) void {
@@ -4542,6 +4540,20 @@ pub const Editor = struct {
     }
     pub const unindent_meta: Meta = .{ .description = "Unindent current line", .arguments = &.{.integer} };
 
+    pub fn scroll_up(self: *Self, ctx: Context) Result {
+        var count: usize = 1;
+        _ = ctx.args.match(.{tp.extract(&count)}) catch false;
+        self.scroll_up_internal(count);
+    }
+    pub const scroll_up_meta: Meta = .{ .description = "Scroll up", .arguments = &.{.integer} };
+
+    pub fn scroll_down(self: *Self, ctx: Context) Result {
+        var count: usize = 1;
+        _ = ctx.args.match(.{tp.extract(&count)}) catch false;
+        self.scroll_down_internal(count);
+    }
+    pub const scroll_down_meta: Meta = .{ .description = "Scroll down", .arguments = &.{.integer} };
+
     pub fn move_scroll_up(self: *Self, ctx: Context) Result {
         const root = try self.buf_root();
         self.with_cursors_const_repeat(root, move_cursor_up, ctx) catch {};
@@ -4558,15 +4570,19 @@ pub const Editor = struct {
     }
     pub const move_scroll_down_meta: Meta = .{ .description = "Move and scroll down", .arguments = &.{.integer} };
 
-    pub fn move_scroll_left(self: *Self, _: Context) Result {
-        self.view.move_left(tui.config().scroll_step_horizontal) catch {};
+    pub fn scroll_left(self: *Self, ctx: Context) Result {
+        var count: usize = 1;
+        _ = ctx.args.match(.{tp.extract(&count)}) catch false;
+        self.view.move_left(count) catch {};
     }
-    pub const move_scroll_left_meta: Meta = .{ .description = "Scroll left" };
+    pub const scroll_left_meta: Meta = .{ .description = "Scroll left", .arguments = &.{.integer} };
 
-    pub fn move_scroll_right(self: *Self, _: Context) Result {
-        self.view.move_right(tui.config().scroll_step_horizontal) catch {};
+    pub fn scroll_right(self: *Self, ctx: Context) Result {
+        var count: usize = 1;
+        _ = ctx.args.match(.{tp.extract(&count)}) catch false;
+        self.view.move_right(count) catch {};
     }
-    pub const move_scroll_right_meta: Meta = .{ .description = "Scroll right" };
+    pub const scroll_right_meta: Meta = .{ .description = "Scroll right", .arguments = &.{.integer} };
 
     pub fn mouse_scroll_left(self: *Self) void {
         const scroll_step_horizontal = tui.config().scroll_step_horizontal;