Contribution to Issue 1616 (not a solution yet)

config/42style.48k

@@ -62,7 +62,7 @@ OffWithImage			"0"		"."		"«	»"	"+"
 UIUp				"?"		"∫"		"["		"/"
 UIDown				"#"		"∞"		"|"		"*"
 UINoShift			"&"		"@"		"$"		"…"
-OffWithImage			";"		"·"		"{	}"	"!'
+OffWithImage			";"		"·"		"{	}"	"!"
 ]
 
 @ PLANE 6: LOWERCASE UNSHIFTED

config/db48x.48k

@@ -1,4 +1,16 @@
-@  PLANE 0: UNSHIFTED
+@ See "Keyboard interaction" in the Help / Documentation.
+@ See "Key positions" in the Help / Documentation for the Plane titles.
+
+@ Each Plane is an Array or List.
+@ There should be 9 planes.
+@ Each plane should define 37 Mappings, separated by whitespace.
+@ A mapping is either a command or a double quoted string.
+@ An unquoted @ character starts a comment. A comment ends with the next newline.
+
+@ Note that the menu / function keys are excluded from the mappings.
+
+@ Plane 1: unshifted.
+@ The command indicated on the key, in white.
 [
 ToolsMenu	inv		sqrt		pow		MathMenu	UIAlgebraic
 Store	       ToggleCustomMenu	StackMenu	sin		cos		tan
@@ -9,7 +21,8 @@ UILeftShift			"1"		"2"		"3"		-
 UIExit				"0"		UIDecimal	Run		+
 ]
 
-@ PLANE 1: LEFT SHIFTED
+@ Plane 2: left shifted (yellow shift key pressed once).
+@ The command indicated above the key, on the left side, in yellow.
 [
 LastMenu	exp		sq		abs		PowersMenu	EquationsMenu
 ComplexMenu	MemoryMenu	ConstantsMenu	asin		acos		atan
@@ -20,7 +33,8 @@ UIRightShift			ToDecimal	ToggleUserMode	ProgramMenu	ListMenu
 OffWithImage			SystemSetup	Show		"«	»"	Catalog
 ]
 
-@ PLANE 2: RIGHT SHIFTED
+@ Plane 3: right shifted (blue shifted = yellow shift key pressed twice).
+@ The command indicated above the key, on the right side, in blue.
 [
 MainMenu	ln		xroot 		AlgebraMenu	PartsMenu	CharactersMenu
 RealMenu	Library		FractionsMenu	HyperbolicMenu	CircularMenu	AnglesMenu
@@ -31,29 +45,34 @@ UINoShift			DebugMenu	LoopsMenu	TestsMenu	ObjectMenu
 SaveState			FilesMenu	GraphicsMenu	"{	}"	Help
 ]
 
-@ PLANE 3: ALPHA UNSHIFTED
+@ Plane 4: uppercase alpha mode (mode activated with the ALPHA = Shift ENTER key).
+@ The command indicated on the right of the key, in white.
 [
 "A"		"B"		"C"		"D"		"E"		"F"
 "G"		"H"		"I"		"J"		"K"		"L"
 UIEnter				"M"		"N"		"O"		UIBackspace
 UILeft				"P"		"Q"		"R"		"S"
 UIRight				"T"		"U"		"V"		"W"
 UILeftShift			"X"		"Y"		"Z"		"_"
-UIExit				":	:"	","		" "		";"
+UIExit				":	:"	","		" "		Catalog
 ]
 
-@ PLANE 4: ALPHA LEFT SHIFTED
+@ plane 5: uppercase alfa mode, left shifted.
+@ The command indicated to the right of the key, in yellow.
+@ Keys without such a yellow indication, the numerics and basic number operations,
+@ default to what is on the key, in white.
 [
-"Σ"		"^"		"√"		"∂"		"ρ"		"("
+"Σ"		"^"		"√"		"∂"		"σ"		"("
 "▶"		"%"		"π"		"<"		"="		">"
 UILowercase			"⇄"		"±"		"∡"		UIDelete
 UILeft				"7"		"8"		"9"		"÷"
 UIRight				"4"		"5"		"6"		"×"
 UIRightShift			"1"		"2"		"3"		"-"
-OffWithImage			"0"		"."		"«	»"	"+"
+OffWithImage			"0"		UIDecimal	"="		"+"
 ]
 
-@ PLANE 5: ALPHA RIGHT SHIFTED
+@ Plane 6: uppercase alfa mode, right shifted.
+@ The command indicated to the right of the key, in blue.
 [
 "∏"		"∆"		"↑"		"μ"		"θ"		"\"
 "→"		"←"		"↓"		"≤"		"≠"		"≥"
@@ -62,21 +81,23 @@ OffWithImage			"0"		"."		"«	»"	"+"
 UIUp				"?"		"∫"		"["		"/"
 UIDown				"#"		"∞"		"|"		"*"
 UINoShift			"&"		"@"		"$"		"…"
-OffWithImage			";"		"·"		"{	}"	"!'
+OffWithImage			";"		"·"		"{	}"	"!"
 ]
 
-@ PLANE 6: LOWERCASE UNSHIFTED
+@ Plane 7: lowercase alpha mode (mode activated with ALPHA ALPHA).
+@ The command indicated on the right of the key, in white, in lowercase.
 [
 "a"		"b"		"c"		"d"		"e"		"f"
 "g"		"h"		"i"		"j"		"k"		"l"
 UIEnter				"m"		"n"		"o"		UIBackspace
 UILeft				"p"		"q"		"r"		"s"
 UIRight				"t"		"u"		"v"		"w"
 UILeftShift			"x"		"y"		"z"		"_"
-UIExit				":	:"	","		" "		";"
+UIExit				":	:"	","		" "		Catalog
 ]
 
-@ PLANE 7: LOWERCASE LEFT SHIFTED
+@ Plane 8: lowercase alpha mode, left shifted.
+@ Intended to give single uppercase characters while in lowercase alpha mode.
 [
 "A"		"B"		"C"		"D"		"E"		"F"
 "G"		"H"		"I"		"J"		"K"		"L"
@@ -87,7 +108,8 @@ UIRightShift			"X"		"Y"		"Z"		"_"
 OffWithImage			":	:"	","		";"		"?"
 ]
 
-@ PLANE 8: LOWERCASE RIGHT SHIFTED
+@ plane 9: lowercase alpha mode, right shifted.
+@ Intended to give easey access to some often used greek letters.
 [
 "α"		"β"		"γ"		"δ"		"ε"		"φ"
 "Γ"		"θ"		"Δ"		"λ"		"λ"		"ν"

config/legacy.48k

@@ -62,7 +62,7 @@ OffWithImage			"0"		"."		"«	»"	"+"
 UIUp				"?"		"∫"		"["		"/"
 UIDown				"#"		"∞"		"|"		"*"
 UINoShift			"&"		"@"		"$"		"…"
-OffWithImage			";"		"·"		"{	}"	"!'
+OffWithImage			";"		"·"		"{	}"	"!"
 ]
 
 @ PLANE 6: LOWERCASE UNSHIFTED

config/true42.48k

@@ -62,7 +62,7 @@ OffWithImage			"0"		"."		"«	»"	"+"
 UIUp				"?"		"∫"		"["		"/"
 UIDown				"#"		"∞"		"|"		"*"
 UINoShift			"&"		"@"		"$"		"…"
-OffWithImage			";"		"·"		"{	}"	"!'
+OffWithImage			";"		"·"		"{	}"	"!"
 ]
 
 @ PLANE 6: LOWERCASE UNSHIFTED

src/user_interface.cc

@@ -5476,7 +5476,7 @@ bool user_interface::load_keymap(cstring name)
     while (kmap.valid())
     {
         unicode c = kmap.get();
-        if (c == '@')
+        if (c == '@'  && !quoted)
         {
             do { c = kmap.get(); } while (c && c != '\n');
             continue;