more general notion of "user error" including empty message -- NB: Output.error_message needs non-empty string to emit anything;
lcp paulson
lp15@cam.ac.uk paulson
norbert.schirmer@web.de schirmer
schirmer@in.tum.de schirmer
urbanc@in.tum.de urbanc
nipkow@lapbroy100.local nipkow
chaieb@chaieb-laptop chaieb
immler@in.tum.de immler
tsewell@rubicon.NSW.bigpond.net.au tsewell
tsewell@nicta.com.au tsewell
thomas.sewell@nicta.com.au tsewell
kaliszyk@in.tum.de kaliszyk
Philipp\ Meyer meyerp
noschinl@in.tum.de noschinl
brianh@cs.pdx.edu huffman
nik sultana
griff Christian Sternagel
cezarykaliszyk@gmail.com kaliszyk
hellerar@macbroy24.informatik.tu-muenchen.de hellerar
tbourke Timothy Bourke
gerwin.klein@nicta.com.au kleing
Gerwin\ Klein\ <gerwin.klein@nicta.com.au> kleing