yq v4: print all key value pairs with full key path

I'm trying to determine the correct syntax for using yq to print all key/value pairs from a given yaml input using yq v4 - with the desired output having the full key "path". This was possible using v3 such as this:

$ cat << EOF | yq r -p pv - '**'
> a:
>   b: foo
>   c: bar
> EOF
a.b: foo
a.c: bar

but I'm having difficulty wrapping my head around the new syntax.

Any help is greatly appreciated.

$ cat << EOF | yq e '.. | select(. == "*") | {(path | join(".")): .} ' -
> a:
>   b: foo
>   c: bar
> EOF
a.b: foo
a.c: bar

What does this do? Let's go over it:

• .. recursively select all values
• select(. == "*") filter for scalar values (i.e. filter out the value of a)
• (path | join(".")) gets the path as array and joins the elements with .
• {…: .} create a mapping, having the joined paths as keys and their values as values

Edit: to get sequence indexes in square brackets ([0] etc), do

$ cat << EOF | yq e '.. | select(. == "*") | . as $x | { ( [ path | ( .[] | select((. | tag) == "!!int") |= (["[", ., "]"] | join("")) ) ] | join(".") | sub(".\[", "[") ) : $x }' -

This seems like there should be a simpler way to do it, but I don't know yq well enough to figure it out.