diff options
Diffstat (limited to 'luatexbase-attr.dtx')
| -rw-r--r-- | luatexbase-attr.dtx | 92 |
1 files changed, 67 insertions, 25 deletions
diff --git a/luatexbase-attr.dtx b/luatexbase-attr.dtx index dd01e01..c1ba696 100644 --- a/luatexbase-attr.dtx +++ b/luatexbase-attr.dtx @@ -124,17 +124,20 @@ See source file '\inFileName' for details. % \begin{abstract} % In addition to the registers existing in \tex and \etex, \luatex introduces % a new concept: attributes. This package takes care of attribute allocation -% just like Plain TeX and LaTeX do for other registers. +% just like Plain TeX and LaTeX do for other registers, and also provides a +% Lua interface. % \end{abstract} % % \tableofcontents % % \section{Documentation} % +% \subsection{\tex interface} +% % The main macro defined here is |\newluatexattribute|. It behaves in the same % way as |\newcount|. There are also two helper macros: |\setluatexattibute| % sets an attribute's value (locally, but you can use |\global| in front of -% it). |\unsetluatexattribute| unsets an atribute by giving it a special +% it). |\unsetluatexattribute| unsets an attribute by giving it a special % value, depending on \luatex's version; you should always use this macro % in order to be sure the correct special value for your version of \luatex is % used. @@ -143,6 +146,8 @@ See source file '\inFileName' for details. % allocate an attribute the way you can locally allocate a counter using % \file{etex.sty}'s |\loccount|, so no corresponding macro is defined. % +% \subsection{Lua interface} +% % The various Lua functions for manipulating attributes use a number to % designate the attribute. Hence, package writers need a way to know the % number of the attribute associated to |\fooattr| assuming it was defined @@ -159,6 +164,16 @@ See source file '\inFileName' for details. % |luatexbase.attributes.foobar| (mind the absence of backslash here) at any % time. % +% Also, two Lua functions are provided that are analogous to the above \tex +% macros (actually, the macros are wrappers around the functions): +% |luatexbase.new_attributes|\parg{name} allocates a new attribute, without +% defining a corresponding \tex control sequence (only an entry in +% |luatexbase.attributes| is created. It usually returns the number of the +% allocated attribute. If room is missing, it raises an error, unless the +% second argument (optional) is not false, in which case it returns -1. +% +% |luatexbase.unset_attribute|\parg{name} unsets an existing attribute. +% % \section{Implementation} % % \subsection{\tex package} @@ -288,39 +303,32 @@ See source file '\inFileName' for details. % % \subsection{User macros} % -% The allocaton macro. Unlike other registers, allocate starting from 1. -% Some code (eg, font handling coming from Con\tex{}t) behaves strangely -% with \verb+\attribute0+ and since there is plenty of room here, it -% doesn't seem bad to ``loose'' one item in order to avoid this problem. +% The allocaton macro is merely a wrapper around the Lua function, but +% handles error and logging in \tex, for consistency with other allocation +% macros. % % \begin{macrocode} -\newcount\lltxb@attribute@alloc -\lltxb@attribute@alloc\z@ \def\newluatexattribute#1{% - \ifnum\lltxb@attribute@alloc<65535\relax - \global\advance\lltxb@attribute@alloc\@ne - \allocationnumber\lltxb@attribute@alloc + \begingroup\escapechar\m@ne \expandafter\expandafter\expandafter + \endgroup \expandafter\expandafter\expandafter + \allocationnumber \luatexbase@directlua{tex.write( + luatexbase.new_attribute("\luatexluaescapestring{\string#1}", true))}% + \ifnum\allocationnumber>\m@ne \global\luatexattributedef#1=\allocationnumber - \unsetluatexattribute#1% - \begingroup\escapechar\m@ne - \luatexbase@directlua{luatexbase.attributedef_from_tex( - '\luatexluaescapestring{\string#1}', '\number\allocationnumber')}% - \endgroup \wlog{\string#1=\string\luatexattribute\the\allocationnumber}% \else \errmessage{No room for a new \string\attribute}% \fi} % \end{macrocode} % -% Helper macro |\unsetluatexattribute|: depends on \luatex's version. +% Helper macro |\unsetluatexattribute|: wrapper around the Lua function. % % \begin{macrocode} \def\unsetluatexattribute#1{% - \ifnum\luatexversion<37\relax - #1=-1\relax - \else - #1=-"7FFFFFFF\relax - \fi} + \begingroup\escapechar\m@ne + \luatexbase@directlua{% + luatexbase.unset_attribute("\luatexluaescapestring{\string#1}")}% + \endgroup} % \end{macrocode} % % And now the trivial helper macro. @@ -344,12 +352,44 @@ See source file '\inFileName' for details. module('luatexbase', package.seeall) % \end{macrocode} % -% Record the allocation number in a Lua table. +% This table holds the values of the allocated attributes, indexed by name. % % \begin{macrocode} attributes = {} -function attributedef_from_tex(name, number) - attributes[name] = tonumber(number) +% \end{macrocode} +% +% The allocaton function. Unlike other registers, allocate starting from 1. +% Some code (eg, font handling coming from Con\tex{}t) behaves strangely +% with \verb+\attribute0+ and since there is plenty of room here, it +% doesn't seem bad to ``loose'' one item in order to avoid this problem. +% +% \begin{macrocode} +local last_alloc = 0 +function new_attribute(name, silent) + if last_alloc >= 65535 then + if silent then + return -1 + else + error("No room for a new \\attribute", 1) + end + end + last_alloc = last_alloc + 1 + attributes[name] = last_alloc + unset_attribute(name) + if not silent then + texio.write_nl('log', string.format( + 'luatexbase.attributes[%q] = %d', name, last_alloc)) + end + return last_alloc +end +% \end{macrocode} +% +% Unset an attribute the correct way depending on \luatex's version. +% +% \begin{macrocode} +local unset_value = (luatexbase.luatexversion < 37) and -1 or -2147483647 +function unset_attribute(name) + tex.setattribute(attributes[name], unset_value) end % \end{macrocode} % @@ -373,6 +413,8 @@ end \unsetluatexattribute\testattr \catcode64 11 \luatexbase@directlua{assert(luatexbase.attributes.testattr)} +\luatexbase@directlua{luatexbase.new_attribute('luatestattr')} +\luatexbase@directlua{assert(luatexbase.attributes.luatestattr)} \begingroup \escapechar64 \newluatexattribute\anotherattr |