Tor Didriksen wrote:
> On Mon, 22 Jun 2009 19:12:08 +0200, Roy Lyseng <Roy.Lyseng@stripped> wrote:
>
>>
>>
>> Konstantin Osipov wrote:
>>> * Tor Didriksen <Tor.Didriksen@stripped> [09/06/22 17:23]:
>>>
>>>> "Structure types are typedef'ed to an all-upper-case identifier."
>>>> Can someone explain the reasoning behind this?
>>>> ALL_UPPERCASE_NAME says DANGEROUS_THIS_IS_A_MACRO to me, rather than
>>>> struct/class.
>>>>
>>>> typedef struct foo { ... } FOO;
>>>> Is legacy C-style, and does not belong in a C++ style guide (imho).
>>>>
>>>> Roy had an email about this:
>>>> http://lists.mysql.com/internals/36570
>>>> I could find no objections to his mail, the thread simply died.
>>>>
>>>
>>> This is an obsolete convention, but it is still widely used in the
>>> optimizer and semantic analysis code, even in new parts of it. It
>>> was difficult for me to involve some optimizer engineers into
>>> discussion about the coding style.
>>>
>>> In runtime, I find it largely irrelevant: I advocate against
>>> introduction of new struct objects into the code base, classes
>>> should be used instead, and for classes we use a different naming
>>> rule.
>>>
>>> We also have a lot of legacy code that follows this old guideline.
>>> typedef's are really a pain to maintain, since they obfuscate
>>> tags-jumping, make forward declarations more difficult.
>>>
>>> I guess updating the old code could be a task for reengineering
>>> team. Drizle did it one of the first things. I would gladly review
>>> any patch that removes unnecessary typedefs
>>> from the code, and submit such patches myself once in a while.
>>> Nobody else, however, seem to have done much about it instead of
>>> talking :-<.
>>>
>>> Please submit a change request to the coding style group to remove
>>> that rule (unless this mail is already a change request).
>>>
>>>
>>> As Tor said, there is already a proposal:
>>> http://lists.mysql.com/internals/36570.
>>
>> When it is accepted, I will be more than happy to start removing old
>> typedefs. But I consider it a waste of time unless we have a clear rule.
>>
>> Thanks,
>> Roy
>
> Please note that I am not suggesting a major rewrite of existing code.
> I don't think that is productive use of engineer time.
Actually, I think that is a productive use of engineer time. I tried to work out
the dependencies of lex.h (to make it self-sufficient), and this is what I got:
class Table_ident; /* Need to be before include of sql_yacc.h */
class Item_num;
class String;
class Key_part_spec;
struct TABLE_LIST;
typedef struct st_udf_func udf_func;
typedef struct st_lex_user LEX_USER;
#include "sql_list.h" /* Pull in List<> */
#include "set_var.h" /* Pull in sys_var_with_base */
#include "sql_yacc.h" /* Pull in symbol definitions */
For each line, I had to do a symbol search to find the definition of it and see
how and where it was defined. Most other files have similar dependencies...
/Matz
>
> -- didrik
>
>
>
>
--
Mats Kindahl
Senior Software Engineer
Database Technology Group
Sun Microsystems
