erlang中的erl_scan:string

string2value(Str) ->
    {ok, Tokens, _} = erl_scan:string(Str ++ "."),
    {ok, Exprs} = erl_parse:parse_exprs(Tokens),
    Bindings = erl_eval:new_bindings(),
    {value, Value, _} = erl_eval:exprs(Exprs, Bindings),
    Value.

http://www.trapexit.org/String_Eval