// Perform at most one value conversion from the following set:
//
// - integer conversions
// - float conversions
// - numeric conversions (int to float)
// - boolean conversions (type to bool)
//
// Note that all such conversions take value expressions as operands: a
// reference-to-value conversion must have been previously applied to
// a reference expressions.
//
// TODO: Implement integer and floating point promotion.
//
// TODO: Support conversion of T[N] to T[].
//
// TODO: Support pointer conversions.
//
// TODO: Support character conversions separately from integer
// conversions?
Expr&
convert_value(Context& cxt, Expr& e, Type& t)
{
try {
// Note that errors here are not fatal. If we can't find a conversion,
// that doesn't mean the program is ill-formed.
Suppress_diagnostics guard(cxt);
debug(e);
debug(t);
// Search for a list of conversion operators for the given type.
Name& id = cxt.get_conversion_id(t);
Decl_list decls = unqualified_lookup(cxt, id);
// FIXME: What do I do with ambiguous resolutions? Fail to convert?
Resolution res = resolve_call(cxt, decls, e);
Function_decl& decl = res.function();
Expr_list& args = res.arguments();
// Build a call to the selected conversion.
Expr& fn = cxt.make_reference(decl.type(), decl);
Call_expr& conv = cxt.make_call(decl.return_type(), fn, std::move(args));
conv.res_ = &decl;
return conv;
}
catch (...) {
return e;
}
return e;
}
// Perform unqualified lookup.
//
// TODO: Allow an lookup to fail, indicating that we could not find
// a name. In function calls, this could be used to perform class
// lookup for member functions.
Expr&
make_reference(Context& cxt, Simple_id& id)
{
Decl_list decls = unqualified_lookup(cxt, id);
if (decls.size() == 1)
return make_decl_ref(cxt, decls.front());
else
return make_ovl_ref(cxt, id, std::move(decls));
}
// Perform unqualified lookup.
Expr&
make_reference(Context& cxt, Simple_id& id)
{
Decl_list decls = unqualified_lookup(cxt, id);
if (decls.size() == 1)
return make_reference(cxt, decls.front());
// TODO: Return a reference to an overload set.
banjo_unhandled_case(id);
}