Re: Add new for_each macros for iterating over a List that do not require ListCell pointer

On 2023-Oct-24, Jelte Fennema wrote:

> Many usages of the foreach macro in the Postgres codebase only use the
> ListCell variable to then get its value. This adds macros that
> simplify iteration code for that very common use case. Instead of
> passing a ListCell you can pass a variable of the type of its
> contents. This IMHO improves readability of the code by reducing the
> total amount of code while also essentially forcing the use of useful
> variable names.

+1 for getting rid of useless "lc" variables.

Looking at for_each_ptr() I think it may be cleaner to follow
palloc_object()'s precedent and make it foreach_object() instead (I have
no love for the extra underscore, but I won't object to it either).  And
like foreach_node, have it receive a type name to add a cast to.

I'd imagine something like

  SubscriptionRelState *rstate;

  foreach_object(SubscriptionRelState *, rstate, table_states_not_ready)
  {

-- 
Álvaro Herrera               48°01'N 7°57'E  —  https://www.EnterpriseDB.com/