Parser does not parse grammar with arithmetic symbols in input alphabet
This does not work:
> print string::Parse @grammar::Grammar "CFG({S}, {+, *, (, )}, {S -> }, S)"
0 [Standard exception]: Evaluation of algorithm string::Parse failed.
1 [Common exception]: Parse callback not registered.
One has to replace the symbols with text symbols
> print string::Parse @grammar::Grammar "CFG({S}, {plus, star, lpar, rpar}, {S -> }, S)"
(CFG nonterminalAlphabet = {S}terminalAlphabet = {lpar, plus, rpar, star}initialSymbol = Srules = {(S, {[]})})
Possibly related to #209