[C++-0x] User defined literals.
Ed Smith-Rowland
3dw4rd@verizon.net
Wed Jul 20 22:09:00 GMT 2011
On 07/12/2011 04:56 PM, Jason Merrill wrote:
> A few more notes:
>
>> + if (DECL_NAMESPACE_SCOPE_P (decl))
>> + {
>> + if (!check_literal_operator_args(decl,
>> + &long_long_unsigned_p, &long_double_p))
>> + {
>> + error ("%qD has illegal argument list", decl);
>> + return NULL_TREE;
>> + }
>> +
>> + if (CP_DECL_CONTEXT (decl) == global_namespace)
>> + {
>> + const char *suffix = UDLIT_OP_SUFFIX (DECL_NAME (decl));
>> + if (long_long_unsigned_p)
>> + {
>> + if (cpp_interpret_int_suffix (suffix, strlen
>> (suffix)))
>> + warning (0, "integer suffix shadowed by
>> implementation");
>> + }
>> + else if (long_double_p)
>> + {
>> + if (cpp_interpret_float_suffix (suffix, strlen
>> (suffix)))
>> + warning (0, "floating point suffix"
>> + " shadowed by implementation");
>> + }
>> + }
>> + }
>
> Doesn't the shadowing apply everywhere, not just at file scope?
>
>> + if (cpp_userdef_string_p (tok->type))
>> + {
>> + string_tree = USERDEF_LITERAL_VALUE (tok->u.value);
>> + tok->type = cpp_userdef_string_remove_type (tok->type);
>> + curr_tok_is_userdef_p = true;
>> + }
>
> It seems like a mistake to change tok->type without changing the
> value. Why not just set the 'type' local variable appropriately?
>
>> + const char *curr_suffix = IDENTIFIER_POINTER (suffix_id);
>> + if (have_suffix_p == 0)
>> + {
>> + suffix = xstrdup (curr_suffix);
>> + have_suffix_p = 1;
>> + }
>> + else if (have_suffix_p == 1 && strcmp (suffix,
>> curr_suffix) != 0)
> ...
>> + USERDEF_LITERAL_SUFFIX_ID (literal) = get_identifier (suffix);
>
> Just remember the identifier and compare it with ==. Identifiers are
> unique.
>
>> + /* Lookup the name we got back from the id-expression. */
>> + decl = cp_parser_lookup_name (parser, name,
>
> Maybe use lookup_function_nonclass?
>
> Jason
>
>
I was conflating shadowing because of the preprocessor capturing
suffixed like F for float and L for long int, etc. (which are captured
by te preprocessor for those purposes) with allowing two user-specified
suffixes to be disambiguated with namespaces and using declarations as
mentioned in the paper.
I removed those tests.
Now I have a real question: Since a shadowed suffix *cannot* act like
the user wants no matter what, should I error instead of warn?
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