On 7/7/2022 3:15 AM, Max Chernoff via ntg-context wrote:
Hi,
With the latest upload, "tex.linebreak" doesn't return an "info" table.
When running this code:
\startluacode
function test(head)
local new_head, info = tex.linebreak(node.copylist(head))
print(head, type(head), info, type(info))
if info == nil then
print "!!! info is nil !!!"
end
return head
end
nodes.tasks.appendaction("processors", "after", "test")
\stopluacode
\starttext
Hello!
\stoptext
with the latest upload I get (also note the small typo in "rigthfill"):
luatex warning > linebreak: no [ leftinit | rightinit | leftfill |
rigthfill] expected
<node : nil <= 2265 => 2353 : par vmodepar>
userdata nil nil
!!! info is nil !!!
<node : nil <= 2475 => 2299 : glue userskip>
userdata nil nil
!!! info is nil !!!
but with live.contextgarden.net I get:
luatex warning > tex: left parfill skip is gone
Underfull \hbox (badness 10000) in paragraph at lines 20--1
<node : nil <= 936 => 929 : par vmode_par> userdata
table: 0x39a050f7000 table
<node : nil <= 1529 => 1561 : glue userskip> userdata
nil nil
!!! info is nil !!!
This is because you need to pass a list that conforms to what the
builder expects and the callback that you use doesn't do that for you
(after all, it also gets hbox content).
There is no 'callback sequence handler' for the par builder (currently i
see no need for it, also given the extra overhead involved) but this
what what you can do:
\startluacode
function builders.paragraphs.constructors.methods.preroll_a(head)
local result, info = tex.linebreak(head)
tex.prevdepth = info.prevdepth
tex.prevgraf = info.prevgraf
return result
end
function builders.paragraphs.constructors.methods.preroll_b(head)
local result, info = tex.linebreak(nodes.nuts.copylist(head))
inspect(info)
return true
end
\stopluacode
\defineparbuilder[preroll_a]
\defineparbuilder[preroll_b]
\starttext
\setmainparbuilder[default] \input tufte \par \input tufte \page
\setmainparbuilder[preroll_a] \input tufte \par \input tufte \page
\setmainparbuilder[preroll_b] \input tufte \par \input tufte \page
\stoptext
The tex.linebreak function gets the properly prepared paragraph and can
handle it then. On the to do is a to add a 'prepare' helper that adds
the mandate nodes (par fillers etc) but even then one has to be careful
where linebreak hackery is applied.
Hans
-----------------------------------------------------------------
Hans Hagen | PRAGMA ADE
Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
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