With the latest version of Context Standalone, this command \filler[dots] no
longer works.
Best regards,
Fabrice

\definefiller[dots][left=\dontleavehmode, right=\hskip\ZeroPoint\par]
\starttext
\dorecurse{4}{\filler[dots]}
\stoptext

fab@debian:~$ source context/tex/setuptex
Setting "/home/fab/context/tex" as ConTeXt root.
fab@debian:~$ context ntg19.tex

resolvers       | trees | analyzing 'home:texmf'
mtx-context     | run 1: luatex
--fmt="/home/fab/context/tex/texmf-cache/luatex-cache/context/5fe67e0bfe781ce0dde776fb1556f32e/formats/luatex/cont-en"
--jobname="ntg19"
--lua="/home/fab/context/tex/texmf-cache/luatex-cache/context/5fe67e0bfe781ce0dde776fb1556f32e/formats/luatex/cont-en.lui"
--no-parse-first-line --c:currentrun=1 --c:fulljobname="./ntg19.tex"
--c:input="./ntg19.tex" --c:kindofrun=1 --c:maxnofruns=8 "cont-yes.mkiv"
This is LuaTeX, Version beta-0.80.0 (TeX Live 2015/dev) (rev 5195)
 \write18 enabled.

resolvers       > trees > analyzing 'home:texmf'
open source     > 1 > 1 >
/home/fab/context/tex/texmf-context/tex/context/base/cont-yes.mkiv

ConTeXt  ver: 2015.04.01 12:00 MKIV beta  fmt: 2015.4.3  int:
english/english

system          > 'cont-new.mkiv' loaded
open source     > 2 > 2 >
/home/fab/context/tex/texmf-context/tex/context/base/cont-new.mkiv
close source    > 2 > 2 >
/home/fab/context/tex/texmf-context/tex/context/base/cont-new.mkiv
system          > files > jobname 'ntg19', input './ntg19', result 'ntg19'
fonts           > latin modern fonts are not preloaded
languages       > language 'en' is active
open source     > 2 > 3 > /home/fab/ntg19.tex
fonts           > preloading latin modern fonts (second stage)
fonts           > 'fallback modern-designsize rm 12pt' is loaded

tex error       > error on line 3 in file /home/fab/ntg19.tex: ! Undefined
control sequence


\166>dots:right ->\hskip \ZeroPoint
                                    \par
\spac_fillers_indeed ...\fillerparameter \c!right
                                                  \relax \scratchdimen
\fill...
\syst_helpers_recurse_indeed_yes ...curse_content

\syst_helpers_recurse_indeed
<to be read again>
{
<inserted text>
2
\syst_helpers_recurse_indeed ...the \innerrecurse
                                                  }{#2}
l.3 \dorecurse{4}{\filler[dots]}


1     \definefiller[dots][left=\dontleavehmode, right=\hskip\ZeroPoint\par]
2     \starttext
3 >>  \dorecurse{4}{\filler[dots]}
4     \stoptext
5     %%% Local Variables:
6     %%% Mode: context
7     %%% End:
8


?