Dear all,

There is a problem with \useMPlibrary[txt] at compilation time (ConTeXt  ver: 2012.09.11 20:36 MKIV):

metapost        > loaded: library 'txt' (/opt/context-minimals/texmf-context/tex/context/base/meta-imp-txt.mkiv
! Undefined control sequence.

system          > tex > error on line 149 in file /opt/context-minimals/texmf-context/tex/context/base/meta-imp-txt.mkiv: Undefined control sequence ...

139        \ht\scratchbox\parheight
140        \dp\scratchbox\zeropoint
141        \box\scratchbox
142        \getshapecharacteristics
143        \egroup}
144    
145     \def\setupshapetexts%
146       {\dodoubleempty\getparameters[\??sh]}
147    
148     \setupshapetexts%
149 >>    [\c!bodyfont=]
150    
151     %%%%%%% rotfont nog definieren
152    
153     \doifundefined{RotFont}{\definefont[RotFont][RegularBold]}
154    
155     \def\processfollowingtoken#1% strut toegevoegd
156       {\appendtoks#1\to\MPtoks
157        \setbox\MPbox=\hbox{\RotFont\setstrut\strut\the\MPtoks}%
158        \startMPdrawing
159          n := n + 1 ; len[n] := \the\wd\MPbox ;

<argument> \??sh
                
\setsomevalue #1#2->\expandafter \def \csname #1
                                                #2\endcsname
\syst_helpers_get_parameters_assign_indeed ...{#2}
                                                  {#3}
\syst_helpers_process_comma_item ...mpty \_e_o_p_
                                                  \doubleexpandafter \syst_h...
\syst_helpers_get_parameters ...ss_comma_item #1,]
                                                  ,\_e_o_p_
l.149   [\c!bodyfont=]


The fact is I don’t realy know what it is for, I took it from the wiki (http://wiki.contextgarden.net/User-Defined_Enumerations).
Maybe it is not compatible with Mkiv?

Best regards