Re: [RFC PATCH] hashmap API: introduce for_each_hashmap_entry() helper macro

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 16, 2016, 18:09 UTC
Message-ID: <xmqq37rq5m79.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <1458146346-27959-1-git-send-email-kuleshovmail@gmail.com>

Alexander Kuleshov <kuleshovmail@gmail.com> writes:

Show 15 quoted lines

> diff --git a/hashmap.h b/hashmap.h
> index ab7958a..b8b158c 100644
> --- a/hashmap.h
> +++ b/hashmap.h
> @@ -95,4 +95,11 @@ static inline const char *strintern(const char *string)
>  	return memintern(string, strlen(string));
>  }
>  
> +#define for_each_hashmap_entry(map, type)		\
> +	struct type *entry;				\
> +	struct hashmap_iter iter;			\
> +							\
> +	hashmap_iter_init(map, &iter);			\
> +	while ((entry = hashmap_iter_next(&iter)))
> +

This is an easy way to introduce decl-after-statement, i.e. needs an extra pair of {} around the thing. It also forbids the callers from defining "entry" and "iter" as their own identifier outside the scope of this macro and use them inside the block that is iterated over by shadowing these two variables.

Other than that, it looks like a good concept. The syntax however needs more thought because of the above two issues, I think.