pardes - reads stdin into a +Pager pane, and is a terminal's PAGER and GIT_PAGER, Pager pardes|off to opt out; command panes page through cat

A paging command in a terminal, or run through its pty/run, sat in
less, and a pty/run never answered. `pardes -` now reads stdin to its
end, strips terminal escapes (colour, OSC, overstrike), and shows it:
inside a session as a clean <cwd>/+Pager pane made through pane/new and
back at once, outside one as a new editor whose first pane it is, as
`vim -` does. A terminal's shell gets PAGER and GIT_PAGER set to this
pardes's own path and `-` where the user's environment sets neither;
`Pager off`, a setting in /ctl, init and DumpConfig, leaves terminals
started after it to the environment. A command pane's one-shot shell
keeps cat, its output being a pane already.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 11 insertions, 0 deletions

diff --git a/src/ninep/ctl.zig b/src/ninep/ctl.zig
index e0c4b21b..87339b70 100644
--- a/src/ninep/ctl.zig
+++ b/src/ninep/ctl.zig
@@ -1812,6 +1812,17 @@ test "a look at a file it may not read fails the write naming the file" {
     try testing.expectEqualStrings(expected, refused.reply.ename);
 }
 
+test "Pager is a setting of the root ctl: pardes by default, off taken, anything else refused with its choices" {
+    const p = try withFile(testing.allocator, "x\n");
+    defer p.deinit();
+    const root_ctl = @intFromEnum(tree.TopFile.ctl);
+    try testing.expect(std.mem.indexOf(u8, rd(p, root_ctl, 0, 1 << 16).bytes, "Pager pardes\n") != null);
+    try testing.expectEqual(Status.ok, wr(p, root_ctl, "Pager off\n").reply.status);
+    try testing.expectEqual(config.Runtime.Pager.off, p.settings.pager);
+    try testing.expect(std.mem.indexOf(u8, rd(p, root_ctl, 0, 1 << 16).bytes, "Pager off\n") != null);
+    try testing.expectEqualStrings("bad value in control message; takes pardes, off \"Pager\"", wr(p, root_ctl, "Pager less\n").reply.ename);
+}
+
 test "a refused Del written back through event fails that write, EIO, with its err" {
     const gpa = testing.allocator;
     const p = try withFile(gpa, "text\n");