1 files changed, 61 insertions, 2 deletions

diff --git a/src/Pipe.zig b/src/Pipe.zig
index 1ad7b826..37145edf 100644
--- a/src/Pipe.zig
+++ b/src/Pipe.zig
@@ -35,6 +35,7 @@ pub fn pipeMarker(how: modal.Normal.PipeBehavior) []const u8 {
         .ignore => config.pipe_marker_to,
         .insert => config.pipe_marker_insert,
         .append => config.pipe_marker_append,
+        .keep => config.pipe_marker_keep,
     };
 }
 
@@ -117,7 +118,13 @@ pub fn submitPipe(p: *Pardes, id: usize) void {
         p.gpa.free(inputs);
         return;
     }
-    const command_copy = p.gpa.dupe(u8, command) catch {
+    // `$` wants a verdict per selection where the runner's is all or
+    // nothing: the command runs in a subshell whose exit status becomes the
+    // output, so the runner always succeeds and the answer says which kept
+    const command_copy = (if (how == .keep)
+        std.fmt.allocPrint(p.gpa, "(\n{s}\n) >/dev/null; echo $?", .{command})
+    else
+        p.gpa.dupe(u8, command)) catch {
         for (inputs) |input| p.gpa.free(@constCast(input.bytes));
         p.gpa.free(inputs);
         return;
@@ -202,7 +209,7 @@ fn pipeCut(wait: *const PendingPipe, content: []const u8, i: usize) ?struct { lo
     const hi = @max(range.anchor, range.head);
     if (hi > content.len) return null;
     return switch (wait.how) {
-        .replace, .ignore => .{ .lo = lo, .hi = hi },
+        .replace, .ignore, .keep => .{ .lo = lo, .hi = hi },
         .insert => .{ .lo = lo, .hi = lo },
         .append => .{ .lo = hi, .hi = hi },
     };
@@ -260,6 +267,21 @@ pub fn pipeResponse(
     if (changed) return p.reportError(wait.pane, "pipe", error.FileChangedWhileFiltering);
 
     if (wait.how == .ignore) return;
+    if (wait.how == .keep) {
+        // helix shell_keep_pipe: the primary stays if kept, else the last
+        // kept range takes over; keeping none changes nothing
+        var kept: [panes.Text.max_selections]modal.Selection = undefined;
+        var m: usize = 0;
+        var pri: ?usize = null;
+        for (0..wait.nranges) |i| {
+            if (!std.mem.eql(u8, std.mem.trim(u8, outputs[i], " \n"), "0")) continue;
+            if (i == wait.primary) pri = m;
+            kept[m] = wait.ranges[i];
+            m += 1;
+        }
+        if (m == 0) return;
+        return t.setRanges(content, kept[0..m], &.{}, pri orelse m - 1, wait.explicit);
+    }
 
     const n = wait.nranges;
     var total_output: usize = 0;
@@ -366,6 +388,43 @@ test "| in a tag pipes the tag's own text, and undo there brings it back" {
     try std.testing.expect(std.mem.startsWith(u8, pardes.tagline.curTail(pane), " Save "));
 }
 
+test "$ keeps the selections the command exits 0 on, and a real shell gives that verdict" {
+    const gpa = std.testing.allocator;
+    const p = try Pardes.init(gpa, .{ .tty_only = true });
+    defer p.deinit();
+    while (p.nextEffect()) |_| {}
+    const pane = try p.setTestFile("aa bb cc\n");
+    const ranges = [_]modal.Selection{
+        .{ .anchor = 0, .head = 2 },
+        .{ .anchor = 3, .head = 5 },
+        .{ .anchor = 6, .head = 8 },
+    };
+    pane.body.setRanges(pane.file.?.content, &ranges, &.{}, 1, true);
+    p.update(.{ .key = .{ .cp = '$' } });
+    try std.testing.expectEqualStrings(config.pipe_marker_keep, pane.promptText().?);
+    p.update(.{ .key = .{ .cp = 'g', .text = "grep -v b" } });
+    p.update(.{ .key = .{ .cp = Key.enter } });
+    const id = nextPipeEffect(p) orelse return error.MissingPipeEffect;
+    const request = p.pipe.pipeRequest(id) orelse return error.MissingPipeRequest;
+    try std.testing.expectEqual(@as(usize, 3), request.inputs.len);
+    // the wrapper turns each run's status into its output, as the runner sees it
+    const job = try selection_pipe.Job.copy(gpa, request);
+    defer job.deinit(gpa);
+    var response = selection_pipe.runJob(gpa, std.testing.io, job);
+    defer response.deinit(gpa);
+    try std.testing.expect(response.success);
+    try std.testing.expectEqualStrings("0\n", response.outputs[0]);
+    try std.testing.expectEqualStrings("1\n", response.outputs[1]);
+    p.update(.{ .pipe_resp = .{ .id = id, .success = true, .outputs = response.outputs } });
+    try std.testing.expectEqualStrings("aa bb cc\n", pane.file.?.content);
+    var out: [panes.Text.max_selections]modal.Selection = undefined;
+    const got = pane.body.ranges(pane.file.?.content, 0, &out);
+    try std.testing.expectEqual(@as(usize, 2), got.n);
+    try std.testing.expectEqual(@as(usize, 6), out[1].anchor);
+    // the primary was dropped: the last kept range takes over
+    try std.testing.expectEqual(@as(usize, 1), got.pri);
+}
+
 test "selection pipe replaces all ranges atomically and undo restores them" {
     const gpa = std.testing.allocator;
     const p = try Pardes.init(gpa, .{ .tty_only = true });