From 8485cdaaaa5f26d3c12dbffd07fd9061ed10f56a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Tue, 19 Apr 2022 17:25:06 +0200
Subject: [PATCH] csi: implement CSI > 4n (reset modifyOtherKeys)

---
 CHANGELOG.md           |  4 ++++
 csi.c                  | 18 ++++++++++++++++++
 doc/foot-ctlseqs.7.scd |  8 +++++++-
 3 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 38450ab3..081a513c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -60,6 +60,10 @@
   is similar to `show-urls-launch`, but does not automatically exit
   URL mode after activating an URL
   (https://codeberg.org/dnkl/foot/issues/964).
+* Support for `CSI > 4 n`, disable _modifyOtherKeys_. Note that since
+  foot only supports level 1 and 2 (and not level 0), this sequence
+  does not disable _modifyOtherKeys_ completely, but simply reverts it
+  back to level 1 (the default).
 
 
 ### Changed
diff --git a/csi.c b/csi.c
index d3a76e7f..57cae6b3 100644
--- a/csi.c
+++ b/csi.c
@@ -1497,6 +1497,24 @@ csi_dispatch(struct terminal *term, uint8_t final)
             }
             break; /* final == 'm' */
 
+        case 'n': {
+            int resource = vt_param_get(term, 0, 2);  /* Default is modifyFuncionKeys */
+            switch (resource) {
+            case 0:  /* modifyKeyboard */
+            case 1:  /* modifyCursorKeys */
+            case 2:  /* modifyFunctionKeys */
+                break;
+
+            case 4:  /* modifyOtherKeys */
+                /* We don’t support fully disabling modifyOtherKeys,
+                 * but simply revert back to mode ‘1’ */
+                term->modify_other_keys_2 = false;
+                LOG_DBG("modifyOtherKeys=1");
+                break;
+            }
+            break;
+        }
+
         case 'u': {
             int flags = vt_param_get(term, 0, 0) & KITTY_KBD_SUPPORTED;
 
diff --git a/doc/foot-ctlseqs.7.scd b/doc/foot-ctlseqs.7.scd
index 8f23ebed..2759b625 100644
--- a/doc/foot-ctlseqs.7.scd
+++ b/doc/foot-ctlseqs.7.scd
@@ -563,8 +563,14 @@ manipulation sequences. The generic format is:
 |  \\E[ > 4 ; _Pv_ m
 :  XTMODKEYS
 :  xterm
-:  Set level of the _modifyOtherKey_ property to _Pv_. Note that foot
+:  Set level of the _modifyOtherKeys_ property to _Pv_. Note that foot
    only supports level 1 and 2, where level 1 is the default setting.
+|  \\E[ > 4 n
+:  <unnamed>
+:  xterm
+:  Resets the _modifyOtherKeys_ property to level 1. Note that in foot,
+   this sequence does not completely disable _modifyOtherKeys_, since
+   foot only supports level 1 and level 2 (and not level 0).
 |  \\E[ ? u
 :  <unnamed>
 :  kitty