Suggestion for "syntax error": ++i, --i

[Steven Bethard]

Peter Maas wrote:
> 
> target = 'a='
> sign = '-'
> operand = '-2'
> 
> exec(target+sign+operand)

Hopefully not too many people write code like above when it isn't much 
harder to write this without exec:

 >>> target = 'a'
 >>> sign = '-'
 >>> operand = '-2'
 >>> sign_functions = {'+':operator.pos, '-':operator.neg}
 >>> globals()[target] = sign_functions[sign](int(operand))
 >>> a
2

This avoids fun with exec like:

target = 'a='
sign = '-'
operand = '-2; import os; os.removedirs("/")'

=)

Steve