Hello, given is the following PlainTeX file: %&luatex % \message{\the\currentgrouplevel} \directlua0{texio.write_nl(tex.currentgrouplevel)} \bye This results in: This is LuaTeX, Version snapshot-0.29.0-2008072919 (Web2C 7.5.7) (currentgrouplevel.tex ! You can't use `\currentgrouplevel' as tex library index. l.3 ...lua0{texio.write_nl(tex.currentgrouplevel)} ? Looking into section 4.1.1 of the manual, currentgrouplevel is not in the list of tex's integer parameters -- unfortunately. It would be a quite useful addition in order to create `grouped variables' in Lua (variables whose previous value is restored at the end of a TeX group): -- Assume there are TeX two count registers allocated, `stackIndex' -- and `groupIndex' tex.count.stackIndex = 0 tex.count.groupLevel = -1 -- The `grouped variable' stack local stack = { } -- Sets a `grouped variable' function set(name, value) if tex.currentgrouplevel > tex.count.grouplevel then -- New group opened since the last time. Create a new stack -- element tex.count.stackIndex = tex.count.stackIndex + 1 stack[tex.count.stackIndex] = { } tex.count.groupLevel = tex.currentgrouplevel -- TODO: Optional: Clear the stack above the new element to -- release old values end -- Add the value stack[tex.count.stackIndex][name] = value end -- Gets a `grouped variable' function get(name) -- Look through the stack, top to bottom for i = tex.count.stackIndex, 1, -1 do if stack[i][name] then return stack[i][name] end end -- Value not found return nil end Jonathan
"Jonathan Sauer"
Hello,
given is the following PlainTeX file:
%&luatex
% \message{\the\currentgrouplevel} \directlua0{texio.write_nl(tex.currentgrouplevel)}
\bye
This results in:
This is LuaTeX, Version snapshot-0.29.0-2008072919 (Web2C 7.5.7) (currentgrouplevel.tex ! You can't use `\currentgrouplevel' as tex library index. l.3 ...lua0{texio.write_nl(tex.currentgrouplevel)}
?
Looking into section 4.1.1 of the manual, currentgrouplevel is not in the list of tex's integer parameters -- unfortunately. It would be a quite useful addition in order to create `grouped variables' in Lua (variables whose previous value is restored at the end of a TeX group):
-- Assume there are TeX two count registers allocated, `stackIndex' -- and `groupIndex' tex.count.stackIndex = 0 tex.count.groupLevel = -1
-- The `grouped variable' stack local stack = { }
-- Sets a `grouped variable' function set(name, value) if tex.currentgrouplevel > tex.count.grouplevel then -- New group opened since the last time. Create a new stack -- element tex.count.stackIndex = tex.count.stackIndex + 1 stack[tex.count.stackIndex] = { } tex.count.groupLevel = tex.currentgrouplevel
-- TODO: Optional: Clear the stack above the new element to -- release old values end
-- Add the value stack[tex.count.stackIndex][name] = value end
-- Gets a `grouped variable' function get(name) -- Look through the stack, top to bottom for i = tex.count.stackIndex, 1, -1 do if stack[i][name] then return stack[i][name] end end
-- Value not found return nil end
Would not work anyway. Local values would survive across \endgroup\begingroup Whether or not reading the current group level might be interesting is a different question. But for this application, it is not sufficient. What one would need is something like a unique group _id_, and a means to check whether a certain group id is dead (the group has ended) or not. Something like that. -- David Kastrup
Hello,
-- Assume there are TeX two count registers allocated, `stackIndex' -- and `groupIndex' tex.count.stackIndex = 0 tex.count.groupLevel = -1
-- The `grouped variable' stack local stack = { }
-- Sets a `grouped variable' function set(name, value) if tex.currentgrouplevel > tex.count.grouplevel then -- New group opened since the last time. Create a new stack -- element tex.count.stackIndex = tex.count.stackIndex + 1 stack[tex.count.stackIndex] = { } tex.count.groupLevel = tex.currentgrouplevel
-- TODO: Optional: Clear the stack above the new element to -- release old values end
-- Add the value stack[tex.count.stackIndex][name] = value end
-- Gets a `grouped variable' function get(name) -- Look through the stack, top to bottom for i = tex.count.stackIndex, 1, -1 do if stack[i][name] then return stack[i][name] end end
-- Value not found return nil end
Would not work anyway. Local values would survive across \endgroup\begingroup
Why? At \endgroup, tex.count.stackIndex would be reset to the value it had at the beginning of the group (since it is a tex \count register, not a Lua variable). Then, after \begingroup, setting a variable would notice that tex.count.groupLevel (which would also have been reset to its previous value at \endgroup) is lower than tex.currentgrouplevel, and a new stack element would be created, replacing the previous element for this grouping level.
David Kastrup
Jonathan
"Jonathan Sauer"
Hello,
-- Assume there are TeX two count registers allocated, `stackIndex' -- and `groupIndex'
groupLevel. The code is a bit harder to follow for a human since the names change throughout, and quite a bit harder to follow for Lua...
tex.count.stackIndex = 0 tex.count.groupLevel = -1
-- The `grouped variable' stack local stack = { }
-- Sets a `grouped variable' function set(name, value) if tex.currentgrouplevel > tex.count.grouplevel then -- New group opened since the last time. Create a new stack -- element tex.count.stackIndex = tex.count.stackIndex + 1 stack[tex.count.stackIndex] = { } tex.count.groupLevel = tex.currentgrouplevel
-- TODO: Optional: Clear the stack above the new element to -- release old values end
-- Add the value stack[tex.count.stackIndex][name] = value end
-- Gets a `grouped variable' function get(name) -- Look through the stack, top to bottom for i = tex.count.stackIndex, 1, -1 do if stack[i][name] then return stack[i][name] end end
-- Value not found return nil end
Would not work anyway. Local values would survive across \endgroup\begingroup
Why? At \endgroup, tex.count.stackIndex would be reset to the value it had at the beginning of the group (since it is a tex \count register, not a Lua variable). Then, after \begingroup, setting a variable would notice that tex.count.groupLevel (which would also have been reset to its previous value at \endgroup) is lower than tex.currentgrouplevel, and a new stack element would be created, replacing the previous element for this grouping level.
Ok, the group housekeeping of the TeX counters should do the trick here. -- David Kastrup, Kriemhildstr. 15, 44793 Bochum
David Kastrup
Why? At \endgroup, tex.count.stackIndex would be reset to the value it had at the beginning of the group (since it is a tex \count register, not a Lua variable). Then, after \begingroup, setting a variable would notice that tex.count.groupLevel (which would also have been reset to its previous value at \endgroup) is lower than tex.currentgrouplevel, and a new stack element would be created, replacing the previous element for this grouping level.
Ok, the group housekeeping of the TeX counters should do the trick here.
Anyway, I am not convinced that this poor man's equivalence table for Lua is a sane approach to the problem, regardless whether tex.currentgrouplevel might be nice to have or not. -- David Kastrup, Kriemhildstr. 15, 44793 Bochum
Hello,
-- Assume there are TeX two count registers allocated, `stackIndex' -- and `groupIndex'
groupLevel. The code is a bit harder to follow for a human since the names change throughout, and quite a bit harder to follow for Lua...
Indeed. Unfortunately, Lua is pedantic that way.
Anyway, I am not convinced that this poor man's equivalence table for Lua is a sane approach to the problem,
I was trying to preserve the spirit of TeX the Macro Programming Language.
regardless whether tex.currentgrouplevel might be nice to have or not.
But seriously: What I'm trying to do is to store configuration data (such as list indentation and formatting) as (global) Lua values while preserving TeX's grouping mechanism so changes to the configuration can be local to a group. I want to use Lua values instead of TeX macros/registers, since then I can store complex data structures. Also, access from Lua code is easier and most likely faster. Jonathan
Is \parshape supposed to be finished? It's not working currently as it should (0.29.0). This command appears just once in latex.ltx, but it's critical, because it controls how displayed text is formatted (eg, lists). Javier ------------------------------ http://www.tex-tipografia.com/
Javier Bezos wrote:
Is \parshape supposed to be finished? It's not working currently as it should (0.29.0). This command appears just once in latex.ltx, but it's critical, because it controls how displayed text is formatted (eg, lists).
Thank you. I had a report that latex lists were broken, but did not know why yet. Will fix this asap. Best wishes, Taco
Taco Hoekwater wrote:
Javier Bezos wrote:
Is \parshape supposed to be finished? It's not working currently as it should (0.29.0). This command appears just once in latex.ltx, but it's critical, because it controls how displayed text is formatted (eg, lists).
Thank you. I had a report that latex lists were broken, but did not know why yet. Will fix this asap.
The svn trunk should be ok now. Best wishes, Taco
Hello,
What one would need is something like a unique group _id_, and a means to check whether a certain group id is dead (the group has ended) or not. Something like that.
Maybe a callback could be created: function group_callback(type, where) where "type" would denote if the group was opened/closed using \begingroup/ \endgroup or { }, and "where" would be "before_begin", "after_begin", "before_end", "after_end", so code could be executed inside and outside the group. This callback could then manage group_ids as well as a stack with all living groups: \begingroup (id 1 => stack: 1) \begingroup (id 2 => stack: 1 2) \endgroup (stack: 1) \endgroup (stack: empty) \begingroup (id 3 => stack: 3) ... Also, with this callback, one could create a multi-token aftergroup (since the \endgroup would already have been consumed, anything printed to TeX would be inserted after the end of the group): function group_callback(type, where) if where == "before_end" then -- Assume there is a toks register \aftergroupToks tex.sprint(tex.toks["aftergroupToks"]) end end Example: \begingroup \aftergroupToks={\foo\bar} \endgroup % Now \foo\bar would be inserted here Of course, catcodes would be reassigned. Maybe not what is desired.
David Kastrup
Jonathan
Jonathan Sauer wrote:
Hello,
What one would need is something like a unique group _id_, and a means to check whether a certain group id is dead (the group has ended) or not. Something like that.
Maybe a callback could be created:
function group_callback(type, where)
in that case a more advanced approach is needed - just two callbacks (open_group and close_group), i.e. no need for a type (which would involve a test for each call, and groups occur many times) - information about what kind of group (explicit, implicit, math, alignments, etc) Such an extension probably has to wait till fundamental steps in the roadmap are done (like the upcoming math subproject). Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------
Hello, I created a small patch to add several internal parameters to the "tex" table, among them \currentgrouplevel (the patch is based on the current SVN trunk): % diff --normal luatex.web.orig luatex.web 9829a9830,9831
@!negative:boolean; { always false} @!q:halfword; { general purpose index} 9830a9833 negative:=false; 9844a9848 last_item: @
;
I adapted this from procedure "scan_something_internal" and added local variables until it compiled (ahem). "q" seems unproblematic, "negative" is a parameter in "scan_something_internal", most likely to handle expressions like "-\currentgrouplevel". As this is not used when accessing the parameters from Lua, I set it to "false". I only tested it with \currentgrouplevel, \eTeXversion, \pdflastobj, \pdftexversion and \inputlineno; it seems to work. Example: %&luatex \begingroup \begingroup \directlua0{texio.write_nl(tex.currentgrouplevel)} \directlua0{texio.write_nl(tex.eTeXversion)} \directlua0{texio.write_nl(tex.pdflastobj)} \directlua0{texio.write_nl(tex.pdftexversion)} \directlua0{texio.write_nl(tex.inputlineno)} \endgroup \endgroup \bye This is LuaTeX, Version snapshot-0.29.0-2008082107 (Web2C 7.5.7) (currentgrouplevel.tex 2 2 0 200 9 ) No pages of output. Transcript written on currentgrouplevel.log. Jonathan
participants (5)
-
David Kastrup -
Hans Hagen -
Javier Bezos -
Jonathan Sauer -
Taco Hoekwater