option to force to encode empty table to "[]"

[drmingdrmer]

Since lua-cjson use table index type to decide the result json type that a lua table is
encoded to, there is no way to encode empty lua table to a list in json.

This patch solves this problem by assigning a special meta-table to an
empty table to force it to be encoded to "[]" instead of "{}":

local t = {}
setmetatable(t,cjson.as_array)
json.encode(t) -- > "[]"

[nijikokun]

👍

[ppwfx]

Why is it still open? I need this feature and don't want to fork it..
Is there a workaround for this?

[moooofly]

any progress for this PR?

[drmingdrmer]

@moooofly It seems the author has no intent to merge it. :(

[moooofly]

@drmingdrmer
anyway, this PR helps me a lot, I've patched this code into https://github.com/antirez/redis/blob/unstable/deps/lua/src/lua_cjson.c , and works well.

Thanks a lot.