xml2lua

xml2lua is an XML parser written entirely in Lua which doesn’t depend on any external C/C++ library. It works for Lua 5.1 to 5.3 and enables:

• parsing an XML string into a Lua Table;

• converting a Lua Table to an XML string.

This version was adapted to work with Lua 5 and can be used in Lua applications, including interactive Digital Television (DTV) Ginga NCL applications for the Brazilian DTV System (worldwide known as ISDB-T International or ISDB-Tb).

The original parser was written by Paul Chakravarti and is available on LuaUsers.

1. Installation

1.1. From LuaRocks repository

The best way to download the module is using LuaRocks at the command line:

luarocks install xml2lua

1.2. From local sources

Download the source files using the download button above or type at a terminal:

git clone https://github.com/manoelcampos/xml2lua.git

Finally, enter the directory where the source files were downloaded and type:

luarocks make

2. How to use

2.1. Parsing an XML String into a Lua Table

A simplified example which parses an XML directly from a string is presented below. There are some caveats to deal with when an XML has just one tag. Check the example1.lua for details.

local xml2lua = require("xml2lua")
--Uses a handler that converts the XML to a Lua table
local handler = require("xmlhandler.tree")

local xml = [[
<people>
  <person type="natural">
    <name>Manoel</name>
    <city>Palmas-TO</city>
  </person>
  <person type="legal">
    <name>University of Brasília</name>
    <city>Brasília-DF</city>
  </person>
</people>
]]

--Instantiates the XML parser
local parser = xml2lua.parser(handler)
parser:parse(xml)

--Manually prints the table (since the XML structure for this example is previously known)
for i, p in pairs(handler.root.people.person) do
  print(i, "Name:", p.name, "City:", p.city, "Type:", p._attr.type)
end

2.2. Converting a Lua Table to an XML String

local xml2lua = require("xml2lua")
local people = {
    person = {
        {name="Manoel", city="Palmas-TO", _attr={ type='natural' } },
        {name="Breno", city="Palmas-TO", _attr={ type='legal' } }
    }
}

print("People Table\n")
xml2lua.printable(people)

print()
print("XML Representation\n")
print(xml2lua.toXml(people, "people"))

3. Command line tool

You can use a command line tool to try parsing XML files. Execute lua testxml.lua -help on the terminal for more details.

4. Running tests

4.1. Requirements

You must have installed docker and docker compose.

4.2. How to

make lint # to run the lint check
make test # to run the acceptance tests

5. License

This code is freely distributable under the terms of the MIT license.

6. Authors

• Manoel Campos da Silva Filho http://about.me/manoelcampos

• Paul Chakravarti paulc@passtheaardvark.com