Hi,

I'm trying to typeset a BNF grammar. The module t-bnf appears to not work with mkiv. 

http://ctan.math.washington.edu/tex-archive/macros/context/contrib/context-bnf/doc/context/third/bnf/t-bnf.pdf

tex error       > tex error on line 157 in file /Users/acailliau/context/tex/texmf-modules/tex/context/third/bnf/t-bnf.tex: ! Undefined control sequence

 \c!terminalstart 
                 =\tttf 
\syst_helpers_process_comma_item #1,#2->\if ,#1
                                               ,\expandafter \syst_helpers_p...
 \c!terminalstart =\tttf , \c!terminalstop 
                                          =, \c!nonterminalstart =\mathematics 
\syst_helpers_get_parameters ...cess_comma_item #1
                                                  ,],\_e_o_p_ 
l.157    \c!indentnext=\v!no]
                           

147     \def\setupbnfgrammar%
148       {\dosingleargument\dosetupbnfgrammar}
149     
150     \setupbnfgrammar
151       [\c!terminalstart=\tttf,
152        \c!terminalstop=,
153        \c!nonterminalstart=\mathematics{\langle},
154        \c!nonterminalstop=\mathematics{\rangle},
155        \c!is={ \mathematics{\longrightarrow}},
156        \c!option=\mathematics{\vert},
157 >>     \c!indentnext=\v!no]
158     
159     %D \macros
160     %D   {BNF}
161     %D
162     %D We also define a useful abbreviation to be used for header texts and labels.
163     
164     \logo[BNF]{bnf}
165     
166     %D And we use it here:
167     

Can anyone provides me clues on how to make it work ?

Here is a minimal example: 

\usemodule[t-bnf]

\starttext

\startbnfgrammar[]
<exp>: <num> | <num> "+" <num>
<num>: "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
\stopbnfgrammar

\stoptext

Thanks in advance,

Antoine