Why is OPTIND messing my positional params?

Question

I have this function:

    sgrep () 
{ 
    local OPTIND;
    if getopts i o; then
        grep --color=auto -P -in \"$1\" \"$2\";
        shift $((OPTIND-1));
           


        

Answer 1

I have changed the positional params to one bigger:

sgrep () 
    { 
        local OPTIND;
        if getopts i o; then
            grep --color=auto -P -in "$2" "$3";
            shift $((OPTIND-1));
        else
            grep --color=auto -P -n "$1" "$2";
        fi | sed -E -n 's/^([0-9]+).*/\1/p' | xargs -I{} vim +"{}" "$2";
        stty sane
    }

Which works, but I don't like it. In one branch I have to use bigger positions, because of the option, but on the other branch without option used, positions do not change. It is messy

I have tried to put shift $((OPTIND-1)) immediately after then but for no avail.