use and document new {Empty} quickfort keycode

data/quickfort/aliases-common.txt

@@ -16,7 +16,7 @@
 # naming aliases
 ##################################
 
-name:     {Right}
+name:     {Empty}
 givename: !n{name}&
 namezone: ^i{givename}^q
 
@@ -34,7 +34,7 @@ enter_sp_config_hauling: &
 quantum_enable: {enableanimals}{enablefood}{enablefurniture}{enablestone}{enableammo}{enablecoins}{enablebars}{enablegems}{enablefinishedgoods}{enableleather}{enablecloth}{enablewood}{enableweapons}{enablearmor}{enablesheet}
 quantum: {linksonly}{nocontainers}{quantum_enable}{givename}
 
-stop_name: {Right}
+stop_name: {Empty}
 route_enable: {quantum_enable}{enablecorpses}{enablerefuse}
 quantumstop: ^hrn{name}&sn{stop_name}&&xxx{route_enable enter_sp_config={enter_sp_config_hauling}}s{move}p^{move_back}^q
 quantumstopfromeast: {quantumstop move={Right} move_back={Left}}

docs/guides/quickfort-alias-guide.rst

@@ -135,6 +135,12 @@ useful for blueprints::
     Space
     Tab
 
+There is also one pseudo-keycode that quickfort recognizes::
+
+    Empty
+
+which has an empty expansion. It is primarily useful for defining blank default values for `Sub-aliases`_.
+
 Repetitions
 ~~~~~~~~~~~
 
@@ -194,7 +200,8 @@ main drawbridge::
     {givename name="Front Gate"}
 
 The value that you give the sub-alias ``name`` will be used when the
-``givename`` alias is expanded. Without sub-aliases, we'd have to define ``givename`` like this::
+``givename`` alias is expanded. Without sub-aliases, we'd have to define
+``givename`` like this::
 
     givenameprefix: !n
     givenamesuffix: &
@@ -219,7 +226,14 @@ enable furniture for some specific stockpile like this::
 
     {quantum quantum_enable={enablefurniture}}
 
-If an alias uses a sub-alias in its expansion, but the sub-alias is not defined when the alias is used, quickfort will halt the ``#query`` blueprint with an error. If you want your aliases to work regardless of whether sub-aliases are defined, then you must define them with default values like ``quantum_enable`` above.
+If an alias uses a sub-alias in its expansion, but the sub-alias is not defined
+when the alias is used, quickfort will halt the ``#query`` blueprint with an
+error. If you want your aliases to work regardless of whether sub-aliases are
+defined, then you must define them with default values like ``quantum_enable``
+above. If a default value should be blank, like the ``name`` sub-alias used by
+the ``givename`` alias above, define it with the ``{Empty}`` pesudo-keycode::
+
+    name: {Empty}
 
 Sub-aliases must be in one of the following formats::