1 files changed, 32 insertions, 2 deletions

diff --git a/src/normal_input.zig b/src/normal_input.zig
index 4b047a7f..5fa29bea 100644
--- a/src/normal_input.zig
+++ b/src/normal_input.zig
@@ -125,6 +125,9 @@ pub const Role = enum {
     leader,
     command_line,
     pipe_selection,
+    pipe_selection_to,
+    insert_output,
+    append_output,
     search,
     search_next,
     search_prev,
@@ -180,6 +183,27 @@ pub const State = struct {
     }
 };
 
+/// WHERE a filter's output goes, and whether the selection is its stdin.
+/// helix's `|`, `A-|`, `!` and `A-!` in one word each (commands.rs
+/// `ShellBehavior`); its `$` (keep selections by exit status) is not here yet
+/// because it needs a per-selection verdict rather than one atomic answer.
+pub const PipeBehavior = enum {
+    /// `|` — stdin is the selection, and the output REPLACES it.
+    replace,
+    /// `A-|` — stdin is the selection, and the output is discarded. The text
+    /// is not touched at all; the point is the command's side effect.
+    ignore,
+    /// `!` — no stdin, and the output is inserted BEFORE each selection.
+    insert,
+    /// `A-!` — no stdin, and the output is appended AFTER each selection.
+    append,
+
+    /// Do the selections become stdin? helix's `pipe` flag.
+    pub fn pipes(b: PipeBehavior) bool {
+        return b == .replace or b == .ignore;
+    }
+};
+
 pub const Scope = enum { once, per_selection };
 pub const Direction = enum { backward, forward };
 pub const Motion = enum {
@@ -286,7 +310,10 @@ pub const Action = union(enum) {
     adjust_number: i64,
     leader,
     command_line,
-    pipe_selection,
+    /// helix's five shell commands are one action with a behaviour, because
+    /// they differ only in where the output lands and whether the selection is
+    /// stdin. See `PipeBehavior`.
+    pipe_selection: PipeBehavior,
     search,
     search_step: Direction,
 
@@ -548,7 +575,10 @@ pub fn parse(state: *State, key: Input) Result {
 
     if (key.has(.leader)) return resultAction(.leader);
     if (key.has(.command_line)) return resultAction(.command_line);
-    if (key.has(.pipe_selection)) return resultAction(.pipe_selection);
+    if (key.has(.pipe_selection)) return resultAction(.{ .pipe_selection = .replace });
+    if (key.has(.pipe_selection_to)) return resultAction(.{ .pipe_selection = .ignore });
+    if (key.has(.insert_output)) return resultAction(.{ .pipe_selection = .insert });
+    if (key.has(.append_output)) return resultAction(.{ .pipe_selection = .append });
     if (key.has(.search)) return resultAction(.search);
     if (key.has(.search_next)) return resultAction(.{ .search_step = .forward });
     if (key.has(.search_prev)) return resultAction(.{ .search_step = .backward });