vial: measure space used for vial features

keymap/config.h

@@ -31,6 +31,10 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 // Vial features
 #define DYNAMIC_KEYMAP_LAYER_COUNT 5
+// looks like this DYNAMIC_MACRO_SIZE doesn't change anything
 #define DYNAMIC_MACRO_SIZE 0
-#define VIAL_TAP_DANCE_ENTRIES 0
-#define VIAL_COMBO_ENTRIES 0
+/* 8 entries take only 6 bytes more than 2 entries
+   Thus, 8 and 0 are the only reasonable values. */ 
+#define VIAL_KEY_OVERRIDE_ENTRIES 8
+#define VIAL_TAP_DANCE_ENTRIES 8
+#define VIAL_COMBO_ENTRIES 8

keymap/rules.mk

@@ -2,3 +2,42 @@ VIA_ENABLE = yes
 VIAL_ENABLE = yes
 
 LTO_ENABLE = yes
+
+# 2952 bytes
+QMK_SETTINGS = no          # Vial tab
+# 2144 bytes
+MOUSEKEY_ENABLE = yes      # Mouse keys
+# 544 bytes
+EXTRAKEY_ENABLE = yes      # Audio control and System control
+
+# each of the following features take extra space
+# in three steps
+# - the QMK feature (enables here)
+# - the Vial feature (enabled if VIAL_XXX_ENTRIES > 0)
+# - each vial entry for the feature
+
+# qmk feature : 504 bytes
+# vial feature : there is no special setting
+DYNAMIC_MACRO_ENABLE = no
+
+# qmk feature : doesn't compile with
+#               VIAL_KEY_OVERRIDE_ENTRIES = 0 
+# with 1 vial entry   : 1696 bytes
+# with 2 vial entries : 1814 (+118)
+# with 3 vial entries : 1830 (+16)
+# with 8 vial entries : 1820 (-10) SIC
+KEY_OVERRIDE_ENABLE = no
+
+# 1676 bytes + 50 bytes each entry
+# qmk feature         : 696
+# with 1 vial entry   : 1676 (+980)
+# with 2 vial entries : 1720 (+44)
+# with 8 vial entries : 1714 (-6)
+TAP_DANCE_ENABLE = yes
+
+# 900 bytes + 
+# qmk feature         : 924
+# with 1 vial entry   : 1964 (+940)
+# with 2 vial entries : 2082 (+118)
+# with 8 vial entries : 2046 (-36)
+COMBO_ENABLE = yes