One thing they might do: offer better feedback on an error by treating the input as a 'spelling correction' problem (like http://norvig.com/spell-correct.html h

One thing they might do: offer better feedback on an error by treating the input as a 'spelling correction' problem (like http://norvig.com/spell-correct.html http://norvig.com/spell-correct.html). A useful implementation can be pretty naive when inputs are short -- e.g. my old numerical-expressions parser https://github.com/darius/expr/blob/master/expr/Parser.java https://github.com/darius/expr/blob/master/expr/Parser.java)