[e-lang] term`-x` crashes

[Kevin Reid]

It should be made clear that this is a term syntax error, not a  
numeric problem.

? term`-Infinity`
# problem: <NumberFormatException: Zero length BigInteger>
#
#   - QBuilder#valueMaker(Twine)
#   . <a QBuilder>.valueMaker("-Infinity")
#   @ valueMaker/1
#   - EExpr#evalToPair(Scope)
#   .  
e 
` 
term__quasiParser 
.valueMak...ubstitute(__makeList.run())`.evalToPair(<a Scope>)
#   @ evalToPair/1: <file:/Volumes/Opp/External/Projects/e-on-java/src/ 
esrc/org/erights/e/elang/cmd/cmdMakerMaker.emaker#:span::129:57::129:66>

? term`-x`
# problem: <NumberFormatException: Zero length BigInteger>
#
#   - QBuilder#valueMaker(Twine)
#   . <a QBuilder>.valueMaker("-x")
#   @ valueMaker/1
#   - EExpr#evalToPair(Scope)
#   .  
e 
` 
term__quasiParser 
.valueMak...ubstitute(__makeList.run())`.evalToPair(<a Scope>)
#   @ evalToPair/1: <file:/Volumes/Opp/External/Projects/e-on-java/src/ 
esrc/org/erights/e/elang/cmd/cmdMakerMaker.emaker#:span::129:57::129:66>

-- 
Kevin Reid                            <http://homepage.mac.com/kpreid/>