Merge pull request #8 from lualatex/master

sync with lualatex repo

2 files changed, 42 insertions, 23 deletions

diff --git a/NEWS b/NEWS
index 9ad27e2..311ed94 100644
--- a/NEWS
+++ b/NEWS
@@ -7,7 +7,7 @@
     attr
         - hack to make luatexbase and luatex.sty compatible for attribute
           allocation (same thing should be done for catcodetables)
-        - adding whatsit nodes allocation functions (see doc)
+        - adding user-defined whatsit node allocation functions (see doc)
     modutils
         - adding functions to check the availability and version of a module
         - fixing small error in module date requirement
diff --git a/luatexbase-attr.dtx b/luatexbase-attr.dtx
index d19240b..5b7288f 100644
--- a/luatexbase-attr.dtx
+++ b/luatexbase-attr.dtx
@@ -262,7 +262,7 @@ See the aforementioned source file(s) for copyright and licensing information.
 %
 %    \subsubsection{Primitives needed}
 %
-%    First load \pk{luatexbase-modutils} (hence \pk{luatexbase-loader} 
+%    First load \pk{luatexbase-modutils} (hence \pk{luatexbase-loader}
 %    and \pk{luatexbase-compat}), and make sure \pk{luatex.sty} is loaded too.
 %
 %    \begin{macrocode}
@@ -434,6 +434,8 @@ luatexbase.new_attribute = new_attribute
 %    \end{macrocode}
 %
 %    Unset an attribute the correct way depending on \luatex's version.
+%    The constant \verb+unset_value+ can be retrieved by calling
+%    \verb+get_unset_value()+ to apply to nodes.
 %
 %    \begin{macrocode}
 local unset_value = (luatexbase.luatexversion < 37) and -1 or -2147483647
@@ -441,9 +443,14 @@ function unset_attribute(name)
     tex.setattribute(attributes[name], unset_value)
 end
 luatexbase.unset_attribute = unset_attribute
+luatexbase.get_unset_value = function () return unset_value end
 %    \end{macrocode}
 %
-%    User whatsit allocation (experimental).
+%   Allocation of user-defined whatsit nodes (experimental).
+%   User-defined whatsit nodes (or user whatsits) are ignored by the
+%   \luatex engine. They can thus be used to store information in
+%   node lists without doing any harm. User whatsits can be
+%   distinguished by an id that is stored in node field |user_id|.
 %
 %    \begin{macrocode}
 --- cf. luatexref-t.pdf, sect. 8.1.4.25
@@ -457,18 +464,18 @@ local anonymous_whatsits  = 0
 local anonymous_prefix    = "anon"
 %    \end{macrocode}
 %
-%    The whatsit allocation is split into two functions:
+%    User whatsit allocation is split into two functions:
 %    \verb|new_user_whatsit_id| registers a new id (an integer)
 %    and returns it. It is up to the user what he actually does
 %    with the return value.
 %
-%    Registering whatsits without a name, though supported, is
+%    Registering user whatsits without a name, though supported, is
 %    not exactly good style. In these cases we generate a name
 %    from a counter.
 %
-%    In addition to the whatsit name, it is possible and even
+%    In addition to the user whatsit name, it is possible and even
 %    encouraged to specify the name of the package that will be
-%    using the whatsit as the second argument.
+%    using the user whatsit as the second argument.
 %
 %    \begin{macrocode}
 --- string -> string -> int
@@ -512,23 +519,36 @@ luatexbase.new_user_whatsit_id = new_user_whatsit_id
 %    \end{macrocode}
 %
 %    \verb|new_user_whatsit| first registers a new id and then also
-%    creates the corresponding whatsit of subtype “user defined”.
+%    creates the corresponding whatsit node of subtype “user-defined”.
 %    We return a nullary function that delivers copies of the whatsit.
 %
+%    Alternatively, the first argument can be a whatsit node that
+%    will then be used as prototype. Note that in this case a
+%    \emph{copy} of the prototype will be stored in the closure,
+%    eliminating side-effects.
+%
 %    \begin{macrocode}
---- string -> string -> (unit -> node_t, int)
-local new_user_whatsit = function (name, package)
-    local id         = new_user_whatsit_id(name, package)
-    local whatsit    = newnode(whatsit_t, user_defined_t)
-    whatsit.user_id  = id
-    --- unit -> node_t
-    return function ( ) return copynode(whatsit) end, id
+--- (string | node_t) -> string -> ((unit -> node_t) * int)
+local new_user_whatsit = function (req, package)
+    local id, whatsit
+    if type(req) == "string" then
+        id              = new_user_whatsit_id(req, package)
+        whatsit         = newnode(whatsit_t, user_defined_t)
+        whatsit.user_id = id
+    elseif req.id == whatsit_t and req.subtype == user_defined_t then
+        id      = req.user_id
+        whatsit = copynode(req)
+        if not whatsit_ids[id] then
+            warning("whatsit id %d unregistered; "
+                    .. "inconsistencies may arise", id)
+        end
+    end
+    return function () return copynode(whatsit) end, id
 end
 luatexbase.new_user_whatsit         = new_user_whatsit
-luatexbase.new_user_whatsit_factory = new_user_whatsit --- for Stephan
 %    \end{macrocode}
 %
-%    If one knows the name of a whatsit, its corresponding id
+%    If one knows the name of a user whatsit, its corresponding id
 %    can be retrieved by means of \verb|get_user_whatsit_id|.
 %
 %    \begin{macrocode}
@@ -545,11 +565,11 @@ luatexbase.get_user_whatsit_id = get_user_whatsit_id
 %    The inverse lookup is also possible via \verb|get_user_whatsit_name|.
 %    Here it finally becomes obvious why it is beneficial to supply a package
 %    name -- it adds information about who created and might be relying on the
-%    whatsit in question. First return value is the whatsit name, the second
-%    the package identifier it was registered with.
+%    user whatsit in question. First return value is the user whatsit name, the
+%    second the package identifier it was registered with.
 %
-%    We issue a warning and return empty strings in case the asked whatsit is
-%    unregistered.
+%    We issue a warning and return empty strings in case the argument
+%    doesn't correspond to a registered user whatsit id.
 %
 %    \begin{macrocode}
 --- int | fun | node -> (string, string)
@@ -611,7 +631,7 @@ local dump_registered_whatsits = function (asked_package)
     --- mess up line breaking, so concatenation is unusable ...
     local first = true
     for i=1, #whatsit_list do
-        if first then 
+        if first then
             first = false
         else -- indent
             texiowrite_nl"  "
@@ -626,7 +646,6 @@ luatexbase.dump_registered_whatsits = dump_registered_whatsits
 %    \begin{macrocode}
 luatexbase.newattribute            = new_attribute
 luatexbase.newuserwhatsit          = new_user_whatsit
-luatexbase.newuserwhatsitfactory   = new_user_whatsit_factory
 luatexbase.newuserwhatsitid        = new_user_whatsit_id
 luatexbase.getuserwhatsitid        = get_user_whatsit_id
 luatexbase.getuserwhatsitname      = get_user_whatsit_name