Subject: Re: [PATCH iproute2 v3 1/3] configure: support --param=value style

From: Phil Sutter <[email-masked]>
Date: Wed, 6 Oct 2021 10:09:44 +0200

Hi Andrea,

A remark regarding coding style:

On Wed, Oct 06, 2021 at 12:08:04AM +0200, Andrea Claudi wrote:
[...]
> diff --git a/configure b/configure
> index 7f4f3bd9..d57ce0f8 100755
> --- a/configure
> +++ b/configure
> @@ -501,18 +501,30 @@ if [ $# -eq 1 ] && [ "$(echo $1 | cut -c 1)" != '-' ]; then
>  else
>  	while true; do
>  		case "$1" in
> -			--include_dir)
> -				INCLUDE=$2
> -				shift 2 ;;
> -			--libbpf_dir)
> -				LIBBPF_DIR="$2"
> -				shift 2 ;;
> -			--libbpf_force)
> -				if [ "$2" != 'on' ] && [ "$2" != 'off' ]; then
> +			--include_dir | --include_dir=*)

So here the code combines the two cases,

> +				INCLUDE="${1#*=}"
> +				if [ "$INCLUDE" == "--include_dir" ]; then

just to fiddle it apart again. Did you consider leaving the old cases in
place and adding separate ones for the --opt=val cases like so:

| 			--include_dir=*)
| 				INCLUDE="${1#*=}"
| 				shift
| 				;;

[...]
> +			--libbpf_force | --libbpf_force=*)
> +				LIBBPF_FORCE="${1#*=}"
> +				if [ "$LIBBPF_FORCE" == "--libbpf_force" ]; then
> +					LIBBPF_FORCE="$2"
> +					shift
> +				fi
> +				if [ "$LIBBPF_FORCE" != 'on' ] && [ "$LIBBPF_FORCE" != 'off' ]; then

To avoid duplication here, I would move semantic checks into a second
step. This would allow for things like:

| --libbpf_force=invalid --libbpf_force=on

but separating the syntactic parsing from semantic checks might be
beneficial by itself, too.

Cheers, Phil