json.fl

# json.fl -- one object, out to text and back again.
#
# run it:  ./flint examples/json.fl
#
# objects become tables, arrays lists, and json null becomes nil: those are
# the only container types flint has, so there is nothing else json could
# become. stringify is compact, pretty is the same thing indented, and the
# round trip below is the part worth copying.

import json

let cfg = {
    name: "flint",
    tags: ["fast", "small"],
    meta: {stars: 42, active: true, owner: nil}
}

print(json.stringify(cfg))
print(json.pretty(cfg))

# back again, which is the point
let back = json.parse(json.stringify(cfg))
print(back.name)        # "flint"
print(back.tags[1])     # "small"
print(back.meta.stars)  # 42
print(back.meta.owner)  # nil, out of a json null
print(back.meta.missing)  # nil, not an error: a table read of an absent key

# malformed input is a runtime error naming the offset, so it catches
try {
    json.parse("{oops}")
} catch e {
    print("caught: " + e.message)
}