terminal: RIS should reset tabstops, ESC ? W should reset every 8

Fixes #648

Two issues here:

  - RIS should've been resetting the tabstops to every 8, but was
    clearing all tabstops.

  - `ESC ? W` should've reset tabstops to every 8, but was clearing
    all tabstops.

src/terminal/Terminal.zig

@@ -1487,6 +1487,11 @@ pub fn tabSet(self: *Terminal) void {
     self.tabstops.set(self.screen.cursor.x);
 }
 
+/// TODO: test
+pub fn tabReset(self: *Terminal) void {
+    self.tabstops.reset(TABSTOP_INTERVAL);
+}
+
 /// Carriage return moves the cursor to the first column.
 pub fn carriageReturn(self: *Terminal) void {
     const tracy = trace(@src());
@@ -1922,7 +1927,7 @@ pub fn fullReset(self: *Terminal, alloc: Allocator) void {
     self.screen.charset = .{};
     self.modes = .{};
     self.flags = .{};
-    self.tabstops.reset(0);
+    self.tabstops.reset(TABSTOP_INTERVAL);
     self.screen.cursor = .{};
     self.screen.saved_cursor = .{};
     self.screen.selection = null;

src/terminal/modes.zig

@@ -169,9 +169,11 @@ const ModeEntry = struct {
 /// they're used within Ghostty or google their values. It is not
 /// valuable to redocument them all here.
 const entries: []const ModeEntry = &.{
+    // ANSI
     .{ .name = "insert", .value = 4, .ansi = true },
 
-    .{ .name = "cursor_keys", .value = 1 },
+    // DEC
+    .{ .name = "cursor_keys", .value = 1 }, // DECCKM
     .{ .name = "132_column", .value = 3 },
     .{ .name = "reverse_colors", .value = 5 },
     .{ .name = "origin", .value = 6 },

src/terminal/stream.zig

@@ -376,10 +376,10 @@ pub fn Stream(comptime Handler: type) type {
                 'W' => {
                     switch (action.params.len) {
                         0 => if (action.intermediates.len == 1 and action.intermediates[0] == '?') {
-                            if (@hasDecl(T, "tabClear"))
+                            if (@hasDecl(T, "tabReset"))
-                                try self.handler.tabClear(.all)
+                                try self.handler.tabReset()
                             else
-                                log.warn("unimplemented tab clear callback: {}", .{action});
+                                log.warn("unimplemented tab reset callback: {}", .{action});
                         },
 
                         1 => switch (action.params[0]) {

src/termio/Exec.zig

@@ -1653,6 +1653,10 @@ const StreamHandler = struct {
         self.terminal.tabSet();
     }
 
+    pub fn tabReset(self: *StreamHandler) !void {
+        self.terminal.tabReset();
+    }
+
     pub fn saveCursor(self: *StreamHandler) !void {
         self.terminal.saveCursor();
     }

website/app/vt/ris/page.mdx

@@ -28,85 +28,3 @@ The full reset operation does the following:
 - Move the cursor to the top-left corner
 - Reset the pending wrap state
 - Reset saved cursor state
-
-## Validation
-
-### DECSLRM V-1: Full Screen
-
-```bash
-printf "\033[1;1H" # move to top-left
-printf "\033[0J" # clear screen
-printf "ABC\n"
-printf "DEF\n"
-printf "GHI\n"
-printf "\033[?69h" # enable left/right margins
-printf "\033[s" # scroll region left/right
-printf "\033[X"
-```
-
-```
-|cBC_____|
-|DEF_____|
-|GHI_____|
-```
-
-### DECSLRM V-2: Left Only
-
-```bash
-printf "\033[1;1H" # move to top-left
-printf "\033[0J" # clear screen
-printf "ABC\n"
-printf "DEF\n"
-printf "GHI\n"
-printf "\033[?69h" # enable left/right margins
-printf "\033[2s" # scroll region left/right
-printf "\033[2G" # move cursor to column 2
-printf "\033[L"
-```
-
-```
-|Ac______|
-|DBC_____|
-|GEF_____|
-| HI_____|
-```
-
-### DECSLRM V-3: Left And Right
-
-```bash
-printf "\033[1;1H" # move to top-left
-printf "\033[0J" # clear screen
-printf "ABC\n"
-printf "DEF\n"
-printf "GHI\n"
-printf "\033[?69h" # enable left/right margins
-printf "\033[1;2s" # scroll region left/right
-printf "\033[2G" # move cursor to column 2
-printf "\033[L"
-```
-
-```
-|_cC_____|
-|ABF_____|
-|DEI_____|
-|GH______|
-```
-
-### DECSLRM V-4: Left Equal to Right
-
-```bash
-printf "\033[1;1H" # move to top-left
-printf "\033[0J" # clear screen
-printf "ABC\n"
-printf "DEF\n"
-printf "GHI\n"
-printf "\033[?69h" # enable left/right margins
-printf "\033[2;2s" # scroll region left/right
-printf "\033[X"
-```
-
-```
-|cBC_____|
-|DEF_____|
-|GHI_____|
-```