Shell split string and convert it to json objects format - bash

Question

I have a string in this format:
string= "[one,two,three,four,five]"
I want to convert it to json format likely, without using any specific tool (jq or other) , I want to do it with pure shell:
[
{"id" : 0 , "word": "one"} ,
{"id" : 1 , "word": "two"} ,
{"id" : 2 , "word": "three"} ,
{"id" : 3 , "word": "four"} ,
{"id" : 4 , "word": "five"}
]
Suggestions ?

Answer 1

There is no legitimate reason not to use tr or jq for this. Portably, you cannot use read -d as below, but this is so absurdly fragile that it's not worth worrying about portability. This works in bash:
$ string="[one,two,three,four,five]"
$ c=0; echo '['; while read -d , i; do
echo "{\"id\" : $((c++)), \"word\": \"${i%]}\"},"
done <<< "${string#[}",; echo ']';
[
{"id" : 0 , "word": "one"},
{"id" : 1 , "word": "two"},
{"id" : 2 , "word": "three"},
{"id" : 3 , "word": "four"},
{"id" : 4 , "word": "five"},
]
At the moment, I can't think of a clean way to eliminate the trailing comma without tr (although I suppose you could use the rather banal if test "$c" -eq 5; then ...., but that's boring) so I'll just propose:
c=0; echo '['; while read -d , i; do
printf "{\"id\" : $((c++)), \"word\": \"${i%]}\"}";
expr $c = 5 | tr 10 ' ,'; done <<< "${string#[}",; echo ']'
I'll reiterate that this is absurdly fragile and only has value as an exercise. Use jq.

Answer 2

This may be still tedious but how about:
string="[one,two,three,four,five]"
out=$(while read -r -d, i; do
printf '{"id" : %d , "word": "%s"},\n' "$((c++))" "${i%]}"
done <<< "${string#[},")
printf "[\n%s\n]\n" "${out%,}"
Output:
[
{"id" : 0 , "word": "one"},
{"id" : 1 , "word": "two"},
{"id" : 2 , "word": "three"},
{"id" : 3 , "word": "four"},
{"id" : 4 , "word": "five"}
]