From afc72ac3db0840d8571dcfb8e2e182a241bdecaf Mon Sep 17 00:00:00 2001 From: Gabriel Schneider Date: Mon, 28 Sep 2026 18:20:33 -0300 Subject: A shell's > on addr no longer resets it, so echo /re/ > addr searches on Truncating addr reset it to #0, so a shell's find-and-replace loop matched the first hit for ever, .+#1 read 1 1 each time, and foo x foo y foo became foobarbarbar... acme resets addr on the first open (xfid.c:105-108), for clients that hold the fid; a shell cannot. Here neither an open nor a truncation resets it: the address written is evaluated from the last one, and 0 or , starts over. Documented as a departure from acme. Co-Authored-By: Claude Opus 5.5 --- src/ninep/pane.zig | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) (limited to 'src/ninep/pane.zig') diff --git a/src/ninep/pane.zig b/src/ninep/pane.zig index f87e43a6..714a2566 100644 --- a/src/ninep/pane.zig +++ b/src/ninep/pane.zig @@ -29,14 +29,15 @@ const Node = tree.Node; /// Filesystem state a pane carries beside its editor state. pub const State = struct { /// The range `data` and `xdata` read and write through. acme clears it - /// when the first client opens `addr` (editors/acme/xfid.c:105), which - /// suits a client that holds the fid open and leaves a shell reading back - /// `0 0` from the address it just wrote. Here it is the pane's own - /// register, cleared by truncating the file, so that `cp addr dot` and + /// when the first client opens `addr` (editors/acme/xfid.c:105-108), + /// which suits a client that holds the fid open; a shell cannot, and + /// would evaluate every `echo /re/ > addr` from #0 and never advance. + /// Here it is the pane's own register, cleared by neither an open nor + /// a truncation: `0` or `,` starts over, and `cp addr dot` and /// `cat addr` answer what was written. addr: Range = .{}, /// The last address written to `addr` failed, so there is none: `data` - /// and `xdata` refuse until one is written or `addr` is truncated, + /// and `xdata` refuse until a good one is written, /// rather than act at the address before it, which acme would do. addr_failed: bool = false, limit: ?Range = null, @@ -634,10 +635,10 @@ pub fn truncate(p: *Pardes, pane: *Pane, file: PaneFile) tree.Status { pane.tag.vsel.active = false; pane.tag.nsel = 0; }, - .addr => { - pf.addr = .{}; - pf.addr_failed = false; - }, + // A shell's `>` truncates before it writes: the address written + // is evaluated from where the last one left off, as with `>>`. + // `0` (or `,`) is how to start over. See State.addr. + .addr => {}, .limit => pf.limit = null, .dot => if (fileOf(pane) != null) setDot(pane, .{}), else => {}, -- cgit v1.3