Re: POC: converting Lists into arrays

On 01/08/2019 01:04, Andres Freund wrote:
> Hi,
> 
> On 2019-07-31 16:00:47 -0700, Andres Freund wrote:
>> On 2019-07-31 15:57:56 -0700, Andres Freund wrote:
>>> I also wonder if a foreach version that includes the typical
>>> (Type *) var = (Type *) lfirst(lc);
>>> or
>>> (Type *) var = castNode(Type, lfirst(lc));
>>> or
>>> OpExpr       *hclause = lfirst_node(OpExpr, lc);
>>>
>>> would make it nicer to use lists.
>>>
>>> foreach_node_in(Type, name, list) could mean something like
>>>
>>> foreach(ListCell *name##_cell, list)
>>> {
>>>      Type* name = lfirst_node(Type, name##_cell);
>>> }
>>
>> s/lfirst/linitial/ of course. Was looking at code that also used
>> lfirst...
> 
> Bullshit, of course.
> 
> /me performs a tactical withdrawal into his brown paper bag.
> 
> 
>> Reminds me that one advantage of macros like the second one would also
>> be to reduce the use of the confusingly named linitial*(), helping newer
>> hackers.
> 
> But that point just had two consecutive embarassing demonstrations...
> 

Yeah, pg_list.h is one file I never close.

-- 
Petr Jelinek
2ndQuadrant - PostgreSQL Solutions for the Enterprise
https://www.2ndQuadrant.com/