[PATCH] libclang: functions to deal with anonymous fields

[Argyrios Kyrtzidis]

On Feb 16, 2014, at 11:49 AM, Loïc Jaquemet <loic.jaquemet at gmail.com> wrote:

>> 
>> +/**
>> + * \brief Visitor invoked for each field found by a traversal.
>> + *
>> + * This visitor function will be invoked for each field found by
>> + * clang_visitCursorFields(). Its first argument is the cursor being
>> + * visited, its second argument is the client data provided to
>> + * clang_visitCursorFields().
>> + *
>> + * The visitor should return one of the \c CXFieldVisitResult values
>> + * to direct clang_visitCursorFields().
>> + */
>> +typedef enum CXFieldVisitResult (*CXFieldVisitor)(CXCursor C,
>> +                                                  CXClientData client_data);
>> 
>> +CINDEX_LINKAGE unsigned clang_Type_visitFields(CXType T,
>> +                                               CXFieldVisitor visitor,
>> +                                               CXClientData client_data);
>> 
>> In general, the visitor is not recursing, right ? In that case why not use a simpler "getNumFields / getField" pair of functions ?
> 
> Well, the source code (AST.Decl.h ) exposes a iterator on its fields.
> Given that in other similar cases a visitor is used, I did the same.
> 
> I did not want to introduce new code/new logic.
> I just want to expose the iterator.
> 
> Do you want me to change it to a "getNumFields / getField" pair of functions ?

I see, the visitor interface is fine.

> 
> 
>> +enum CXFieldVisitResult {
>> 
>> Could you reuse CXVisitorResult instead of introducing a new enum ?
> 
> Yes. I did not see that one.
> Will change that.

After that, LGTM!

> 
> 
>> 
>> 
>> On Feb 10, 2014, at 5:13 PM, Loïc Jaquemet <loic.jaquemet at gmail.com> wrote:
>> 
>>> Hi,
>>> 
>>> I'm pinging back about this patch :
>>> * libclang: Add three functions useful for dealing with anonymous fields.
>>> +clang_Cursor_getOffsetOfField
>>> +clang_Cursor_isAnonymous
>>> +clang_Type_visitFields
>>> 
>>> Currently, there is no function in libclang to access clang logic that
>>> handles anonymous members in a record.
>>> 
>>> Given the current API , there is no direct method to :
>>> a) recover the offset of an anonymous field.
>>> - displayname == spelling == '', clang_Type_getOffset does not work
>>> + new clang_Cursor_getOffsetOfField will expose that information
>>> b) clearly identify that DECL as an anonymous record.
>>> + new clang_Cursor_isAnonymous will expose that information
>>> 
>>> When using clang_visitChildren, an anonymous member will be returned
>>> as a STRUCT_DECL/UNION_DECL.
>>> Currently the libclang user has to re-implement the logic to
>>> differentiate FIELD_DECL in the list of children nodes
>>> For example,
>>> 
>>> struct A {
>>> struct {int a;} typeanon;
>>> struct {
>>>   int bariton;
>>>   union {
>>>     int foo;
>>>     int foo2;
>>>   };
>>> };
>>> int c;
>>> } ;
>>> 
>>> Some children are STRUCT_DECL, some are FIELD_DECL, some are attributes.
>>> Worse,
>>> children[0] == STRUCT_DECL (struct {int a;})
>>> children[1] == FIELD_DECL (typeanon)
>>> children[2] == STRUCT_DECL (anonymous structure)
>>> children[3] == FIELD_DECL (int c)
>>> 
>>> Sometime a STRUCT_DECL is a field (children[2]) sometimes it is just a
>>> STRUCT_DECL.
>>> 
>>> The  new function clang_Type_visitFields will expose the existing
>>> libclang capabilities to list only fields, and not all children node,
>>> as does clang_visitChildren.
>>> 
>>> fields[0] == FIELD_DECL (first structure - typeanon)
>>> fields[1] == FIELD_DECL (second anonymous structure)
>>> fields[2] == FIELD_DECL (int c)
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> --
>>> Loïc Jaquemet
>>> <libclang-visit-fields.201116>
>> 
> 
> 
> 
> -- 
> Loïc Jaquemet