add a "Both Alts; AltGr for level 3" option for switching between groups

This allows the user to switch between layouts with the two Alt keys
(to either the previous or the next group) *and* to use the right Alt
key as third-level chooser.  In the bargain it avoids either Alt key
from producing a different symbol upon key release than upon press.

This improves the fix for issue #316.

Signed-off-by: Benno Schulenberg <bensberg@telfort.nl>

7 files changed, 25 insertions, 0 deletions

diff --git a/rules/0036-lo_s.part b/rules/0036-lo_s.part
index f0dce017..4deb2a92 100644
--- a/rules/0036-lo_s.part
+++ b/rules/0036-lo_s.part
@@ -1,5 +1,6 @@
 ! layout		option			= symbols
   *			grp:alts_toggle		= +group(alts_toggle)
+  *			grp:alt_altgr_toggle	= +group(alt_altgr_toggle)
   *			lv3:ralt_alt		= +level3(ralt_alt)
   *			misc:typo		= +typo(base)
   *			misc:apl		= +apl(level3)
diff --git a/rules/0037-l1o_s.part b/rules/0037-l1o_s.part
index bff67ea9..16413eef 100644
--- a/rules/0037-l1o_s.part
+++ b/rules/0037-l1o_s.part
@@ -1,5 +1,6 @@
 ! layout[1]		option			= symbols
   *			grp:alts_toggle		= +group(alts_toggle):1
+  *			grp:alt_altgr_toggle	= +group(alt_altgr_toggle):1
   *			lv3:ralt_alt		= +level3(ralt_alt):1
   *			misc:typo		= +typo(base):1
   *			misc:apl		= +apl(level3):1
diff --git a/rules/0038-l2o_s.part b/rules/0038-l2o_s.part
index fd711c03..86786f4e 100644
--- a/rules/0038-l2o_s.part
+++ b/rules/0038-l2o_s.part
@@ -1,5 +1,6 @@
 ! layout[2]		option			= symbols
   *			grp:alts_toggle		= +group(alts_toggle):2
+  *			grp:alt_altgr_toggle	= +group(alt_altgr_toggle):2
   *			lv3:ralt_alt		= +level3(ralt_alt):2
   *			misc:typo		= +typo(base):2
   *			misc:apl		= +apl(level3):2
diff --git a/rules/0039-l3o_s.part b/rules/0039-l3o_s.part
index 1e7d5e99..caee66e6 100644
--- a/rules/0039-l3o_s.part
+++ b/rules/0039-l3o_s.part
@@ -1,5 +1,6 @@
 ! layout[3]		option			= symbols
   *			grp:alts_toggle		= +group(alts_toggle):3
+  *			grp:alt_altgr_toggle	= +group(alt_altgr_toggle):3
   *			lv3:ralt_alt		= +level3(ralt_alt):3
   *			misc:typo		= +typo(base):3
   *			misc:apl		= +apl(level3):3
diff --git a/rules/0040-l4o_s.part b/rules/0040-l4o_s.part
index 46ef8934..ab6f4d9c 100644
--- a/rules/0040-l4o_s.part
+++ b/rules/0040-l4o_s.part
@@ -1,5 +1,6 @@
 ! layout[4]		option			= symbols
   *			grp:alts_toggle		= +group(alts_toggle):4
+  *			grp:alt_altgr_toggle	= +group(alt_altgr_toggle):4
   *			lv3:ralt_alt		= +level3(ralt_alt):4
   *			misc:typo		= +typo(base):4
   *			misc:apl		= +apl(level3):4
diff --git a/rules/base.xml b/rules/base.xml
index 0a4e9750..f766f113 100644
--- a/rules/base.xml
+++ b/rules/base.xml
@@ -6962,6 +6962,12 @@
       </option>
       <option>
         <configItem>
+          <name>grp:alt_altgr_toggle</name>
+          <description>Both Alt together; AltGr alone chooses third level</description>
+        </configItem>
+      </option>
+      <option>
+        <configItem>
           <name>grp:ctrls_toggle</name>
           <description>Both Ctrl together</description>
         </configItem>
diff --git a/symbols/group b/symbols/group
index 62cd3011..ab37724e 100644
--- a/symbols/group
+++ b/symbols/group
@@ -360,6 +360,20 @@ xkb_symbols "alts_toggle" {
     };
 };
 
+// Pressing Alt plus AltGr switches to the next or previous group
+// (depending on which one is pressed first).
+partial modifier_keys
+xkb_symbols "alt_altgr_toggle" {
+    key <LALT> {
+        type[Group1]="FOUR_LEVEL",
+        symbols[Group1] = [ Alt_L, Alt_L, ISO_Prev_Group, ISO_Prev_Group ]
+    };
+    key <RALT> {
+        type[Group1]="PC_ALT_LEVEL2",
+        symbols[Group1] = [ ISO_Level3_Shift, ISO_Next_Group ]
+    };
+};
+
 // Pressing the left Shift key switches to the next group.
 partial modifier_keys
 xkb_symbols "lshift_toggle" {