diff options
| -rw-r--r-- | NEWS | 2 | ||||
| -rw-r--r-- | luatexbase-attr.dtx | 63 |
2 files changed, 42 insertions, 23 deletions
@@ -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 |