# Saxmerl
Saxmerl is a parser written in Elixir that parses XML documents into Erlang `:xmerl` document.
## Installation
```elixir
def deps() do
[{:saxmerl, "~> 0.1"}]
end
```
## Feature highlights
* **Memory efficiency and better performance** - Several benchmarkings show that
Saxmerl usually use 4x less memory than `:xmerl` or SweetXml, and is usually
70-90% faster.
* **XPath compatible** - Saxmerl parsed documents can be used with
`:xmerl_xpath` or `SweetXml.xpath`.
## Limitations
Not all features provided by `:xmerl` are supported, such as namespaces.
Even Saxmerl discourages dynamic atom conversion by default (via
`dynamic_atoms?: false`), it is usually more practical to generate atoms
dynamically, because of the fact that `:xmerl_xpath` requires atom conversion of
tags and attributes. Therefore, please always monitor the atom usage of the
virtual machine.
## API Overview
```ex
xml_string = "<body><header><p>Message</p><ul><li>One</li><li><a>Two</a></li></ul></header></body>"
{:ok, root} = Saxmerl.parse_string(xml_string, dynamic_atoms: false)
SweetXml.xpath(
root,
~x"//header",
ul: [
~x"./ul",
a: ~x"./li/a/text()"
]
)
%{ul: %{a: 'Two'}}
```
## Benchmarking
To benchmark yourself, do:
```
mix run bench.exs
```
Result on my local computer:
```
Operating System: macOS
CPU Information: Intel(R) Core(TM) i7-6567U CPU @ 3.30GHz
Number of Available Cores: 4
Available memory: 16 GB
Elixir 1.10.2
Erlang 23.0.3
Benchmark suite executing with the following configuration:
warmup: 2 s
time: 5 s
memory time: 2 s
parallel: 1
inputs: test/support/fixtures/sweet_xml/match.xml, test/support/fixtures/sweet_xml/yahoo_fantasy.xml
Estimated total run time: 36 s
Benchmarking Saxy with input test/support/fixtures/sweet_xml/match.xml...
Benchmarking Saxy with input test/support/fixtures/sweet_xml/yahoo_fantasy.xml...
Benchmarking xmerl with input test/support/fixtures/sweet_xml/match.xml...
Benchmarking xmerl with input test/support/fixtures/sweet_xml/yahoo_fantasy.xml...
##### With input test/support/fixtures/sweet_xml/match.xml #####
Name ips average deviation median 99th %
Saxy 6.35 K 157.59 μs ±21.81% 148.90 μs 305.90 μs
xmerl 3.75 K 266.75 μs ±18.54% 249.90 μs 476.08 μs
Comparison:
Saxy 6.35 K
xmerl 3.75 K - 1.69x slower +109.16 μs
Memory usage statistics:
Name Memory usage
Saxy 70.90 KB
xmerl 253.08 KB - 3.57x memory usage +182.18 KB
**All measurements for memory usage were the same**
##### With input test/support/fixtures/sweet_xml/yahoo_fantasy.xml #####
Name ips average deviation median 99th %
Saxy 468.22 2.14 ms ±14.36% 2.03 ms 3.14 ms
xmerl 254.55 3.93 ms ±19.35% 3.66 ms 6.70 ms
Comparison:
Saxy 468.22
xmerl 254.55 - 1.84x slower +1.79 ms
Memory usage statistics:
Name Memory usage
Saxy 0.84 MB
xmerl 4.01 MB - 4.75x memory usage +3.16 MB
**All measurements for memory usage were the same**
```
## Contributing
Any issues or ideas, feel free to write to https://github.com/qcam/saxmerl/issues.
To start developing:
1. Fork the repository.
2. Write your code and related tests.
3. Create a pull request at https://github.com/qcam/saxmerl/pulls.
