Re: [Tarantool-patches] [PATCH v1 1/1] sql: introduce DECIMAL to SQL built-in functions

[Vladislav Shpilevoy via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

Hi! Thanks for the patch!

> diff --git a/src/box/sql/func.c b/src/box/sql/func.c
> index 5abaf490d..684fcc275 100644
> --- a/src/box/sql/func.c
> +++ b/src/box/sql/func.c
> @@ -258,6 +258,20 @@ func_abs_double(struct sql_context *ctx, int argc, const struct Mem *argv)
>  	mem_set_double(ctx->pOut, arg->u.r < 0 ? -arg->u.r : arg->u.r);
>  }
>  
> +static void
> +func_abs_dec(struct sql_context *ctx, int argc, const struct Mem *argv)
> +{
> +	assert(argc == 1);
> +	(void)argc;
> +	const struct Mem *arg = &argv[0];
> +	if (mem_is_null(arg))
> +		return;
> +	assert(mem_is_dec(arg));
> +	decimal_t dec;
> +	decimal_abs(&dec, &arg->u.d);
> +	mem_set_dec(ctx->pOut, &dec);

You should be able to use the same argument both for in and out
values:

	decimal_abs(&arg->u.d, &arg->u.d);

In the 'documentation' of decNumber it is said to be allowed.
See the comment on the function 'decNumberAbs()'.