json2lua

#! /bin/bash

VERSION="v0.3.3"

# Detect Lua interpreter (prefer LuaJIT 2)
if [ ! -z "${LUA}" ]; then
  if [ -z "$(which ${LUA})" ]; then
    LUA=""
  fi
fi

if [ -z "${LUA}" ]; then
  LUA="luajit2"
  if [ -z "$(which ${LUA})" ]; then
    LUA="luajit"
    if [ -z "$(which ${LUA})" ]; then
      LUA="lua"

      if [ -z "$(which ${LUA})" ]; then
        echo "Error: luajit2, luajit and lua executables not found" >&2
        exit 1
      fi
    fi
  fi
fi

function version()
{
  cat << EOF
JSON to Lua translator ${VERSION}

EOF
}

function usage()
{
  cat << EOF
Usage:

  $0 [options] < in.json > out.lua

Options:

  -h    Print this text
  -v    Print script version
  -n    Do not pretty-print Lua code (default: do pretty-print)
  -wN   Set maximum pretty-print width to N chars (default: 80)
  -iStr Set pretty-print indent to string (default: two spaces, '  ')
  -N    Force object keys to be transformed to numbers
        whenever possible (default: off)
  -e    Do not print terminating EOL (default: do print)
  -r    Prefix data with 'return' (default: off)

EOF
}

NO_PRETTY_PRINT=false
MAX_WIDTH=80
INDENT_STR="  "
FORCE_NUM_KEYS=false
SKIP_TERMINATING_EOL=false
PREFIX_WITH_RETURN=false

while getopts ":hvnw:i:Ner" opt; do
  case ${opt} in
    h)
      version
      usage
      exit 0
      ;;
    v)
      version
      exit 0
      ;;
    n)
      NO_PRETTY_PRINT=true
      ;;
    w)
      MAX_WIDTH="${OPTARG}"
      ;;
    i)
      INDENT_STR="${OPTARG}"
      ;;
    N)
      FORCE_NUM_KEYS=true
      ;;
    e)
      SKIP_TERMINATING_EOL=true
      ;;
    r)
      PREFIX_WITH_RETURN=true
      ;;
    \?)
      echo "unknown option: -${OPTARG}" >&2
      exit 1
      ;;
    :)
      echo "option -${OPTARG} requires an argument" >&2
      exit 1
      ;;
  esac
done

${LUA} -e "

local NO_PRETTY_PRINT = ${NO_PRETTY_PRINT}
local MAX_WIDTH = ${MAX_WIDTH}
local INDENT_STR = '${INDENT_STR}'
local FORCE_NUM_KEYS = ${FORCE_NUM_KEYS}
local SKIP_TERMINATING_EOL = ${SKIP_TERMINATING_EOL}
local PREFIX_WITH_RETURN = ${PREFIX_WITH_RETURN}

--------------------------------------------------------------------------------

pcall(require, 'luarocks.require') -- Ignoring errors

local json_decode, json_util, json_decode_util
do
  local json, err = pcall(require, 'json')
  if not json then
    io.stdout:write(
        err, '\n\n',
        'try running \'luarocks install luajson\'', '\n'
      )
    io.stdout:flush()
    os.exit(1)
  end

  json_util = require('json.util')
  json_decode = require('json.decode')
  json_decode_util = require('json.decode.util')

  if
    FORCE_NUM_KEYS and
    not json_decode_util.setObjectKeyForceNumber
  then
    -- TODO: Traverse table manually in this case.
    error(
        'can\'t force numeric keys:\ninstalled luajson version'
     .. ' does not support setObjectKey option'
      )
  end
end

--------------------------------------------------------------------------------

do -- Bootstrap lua-nucleo
  local res, err = pcall(require, 'lua-nucleo.module')
  if not res then
    io.stdout:write(
        err,
        '\n\n',
        'try running \'luarocks install lua-nucleo\'',
        '\n'
      )
    io.stdout:flush()
    os.exit(1)
  end

  require('lua-nucleo.strict')
end

--------------------------------------------------------------------------------

local input = assert(io.stdin:read('*a'))

-- Using simple decoding since we need nulls to be translated to nils.
local decode_options = json_decode.simple

if FORCE_NUM_KEYS then
  local twithdefaults = import 'lua-nucleo/table-utils.lua' { 'twithdefaults' }

  decode_options = twithdefaults(
      {
        object =
        {
          setObjectKey = json_decode_util.setObjectKeyForceNumber;
        };
      },
      decode_options
    )
end

local data, err = json_decode(input, decode_options)
if err then
  error('luajson error: ' .. err)
end

if PREFIX_WITH_RETURN then
  io.stdout:write('return ')
end

if NO_PRETTY_PRINT or type(data) ~= 'table' then
  local tstr = import 'lua-nucleo/tstr.lua' { 'tstr' }
  io.stdout:write(tstr(data))
else
  local tpretty = import 'lua-nucleo/tpretty.lua' { 'tpretty' }
  io.stdout:write(tpretty(data, INDENT_STR, MAX_WIDTH))
end

if not SKIP_TERMINATING_EOL then
  io.stdout:write('\n')
end

io.stdout:flush()

"