Matthew Vogt wrote:
I realise this is getting out of hand,
indeed :-)
but you get can around this with two layers of implicit conversion :) Like this (I know the real code is templated, this is just illustration):
// return type for boost::io::get struct character : public boost::spirit::safe_bool<character> { // return type for filter::get struct value_type { value_type(const character& src) : c(src.value()) {}
operator char() const { return c; }
private: char c; };
character(void) {} character(char value) : c(value) {}
char value(void) const { return c; }
bool operator_bool(void) const { return good(); }
private: char c; };
struct some_filter // details ommitted { template<typename Source> character::value_type get(Source& src) { character c; if (c = boost::io::get(src)) { // c is good() }; return c; } };
I'm not sure how this works; within some_filter get, do you have to use c.value()?
void user_func(void) { char c = get(some_source); }
Obviously, this is getting further and further and from the original code, but only in terms of comprehension. The filter code itself remains transparent.
I'm going to try using char converion and a safe-bool conversion, except on Borland where the safe-bool conversion will be a plain conversion. If it doesn't work, I''ll go back to good(). Thanks for all your suggestions.
Matt
Jonathan