2011/4/4 Wolfgang Schuster <schuster.wolfgang@googlemail.com>
http://www.pragma-ade.com/show-man-22.htm

I tried the first example from fill-in fields:
\starttext

A few years back, \TEX\ could only produce
\fillinfield [dvi]{\DVI} output,
but nowadays, thanks to \fillinfield {Han The Thanh}, we can also directly produce \fillinfield [pdf] {\PDF}!
Nice eh? Actually, while the first field module was prototyped
in \ACROBAT, the current implementation was debugged in
\fillinfield [pdfTeX] {\PDFTEX}. Field support in \fillinfield
[ConTeXt] {\CONTEXT} is rather advanced and complete and all
kind of fields are supported. One can hook in appearances, and
validation \fillinfield [JavaScripts] {\JAVASCRIPT}’s. Fields
can be cloned and copied, where the latter saves some space. By
using \fillinfield {objects} when suited, this module saves
space anyway.

\stoptext

But I get:
mtx-context     | run 1: luatex --fmt="/home/cecil/ConTeXt/tex/texmf-cache/luatex-cache/context/5fe67e0bfe781ce0dde776fb1556f32e/formats/cont-en" --lua="/home/cecil/ConTeXt/tex/texmf-cache/luatex-cache/context/5fe67e0bfe781ce0dde776fb1556f32e/formats/cont-en.lui" --backend="pdf" "./test"
This is LuaTeX, Version beta-0.65.0-2010121316
 \write18 enabled.
(test.tex

ConTeXt  ver: 2011.03.27 14:48 MKIV  fmt: 2011.3.27  int: english/english

system          > cont-new.mkiv loaded
(/home/cecil/ConTeXt/tex/texmf-context/tex/context/base/cont-new.mkiv
system          > beware: some patches loaded from cont-new.mkiv
)
system          > test.top loaded
(test.top)
fonts           > latin modern fonts are not preloaded
languages       > language en is active
{/home/cecil/ConTeXt/tex/texmf-context/fonts/map/pdftex/context/mkiv-base.map}
fonts           > preloading latin modern fonts (second stage)
(/home/cecil/ConTeXt/tex/texmf-context/tex/context/base/type-siz.mkiv) (/home/cecil/ConTeXt/tex/texmf-context/tex/context/base/type-otf.mkiv){/home/cecil/ConTeXt/tex/texmf/fonts/map/dvips/lm/lm-math.map}{/home/cecil/ConTeXt/tex/texmf/fonts/map/dvips/lm/lm-rm.map}
fonts           > virtual math > unable to resolve name mapsfromchar
fonts           > fallback modern rm 12pt is loaded
system          > begin file test at line 1
! Undefined control sequence.

system          > tex > error on line 4 in file test.tex: Undefined control sequence ...

 1     \starttext
 2    
 3     A few years back, \TEX\ could only produce
 4 >>  \fillinfield [dvi]{\DVI} output,
 5     but nowadays, thanks to \fillinfield {Han The Thanh}, we can also directly produce \fillinfield [pdf] {\PDF}!
 6     Nice eh? Actually, while the first field module was prototyped
 7     in \ACROBAT, the current implementation was debugged in
 8     \fillinfield [pdfTeX] {\PDFTEX}. Field support in \fillinfield
 9     [ConTeXt] {\CONTEXT} is rather advanced and complete and all
10     kind of fields are supported. One can hook in appearances, and
11     validation \fillinfield [JavaScripts] {\JAVASCRIPT}’s. Fields
12     can be cloned and copied, where the latter saves some space. By
13     using \fillinfield {objects} when suited, this module saves
14     space anyway.

l.4 \fillinfield
                 [dvi]{\DVI} output,

What is happening here?

--
Cecil Westerhof