Awesome

Erlang NIF bindings for RE2 regex library

Using re2

The library's API follows the standard Erlang/OTP re API as closely as possible while accounting for the differences in RE2:

$ erl
1> re2:run("Bar-foo-Baz", "FoO", [caseless]).
{match,[<<"foo">>]}
2> re2:replace("Baz-foo-Bar", "foo", "FoO", []).
<<"Baz-FoO-Bar">>
3> {ok, RE} = re2:compile("Foo.*Bar", [caseless]).
{ok,#Ref<0.3540238268.2241986568.233969>}
4> re2:run("Foo-baz-bAr", RE).
{match,[<<"Foo-baz-bAr">>]}

Obtaining re2

Installation via package manager

To use re2, you can add it as a project dependency and let your package manager of choice handle it:

Installation from source into $ERL_LIBS

If you want to make re2 available globally, you can install it from source into your Erlang installation by adding it in one of your $ERL_LIBS paths. So, it's either somewhere like /usr/lib/erlang/lib or $HOME/.erl.

You can either download a tagged release or clone the git repo in the target directory. Once that's done, cd into the directory and run rebar3 compile or just make.

Now, if you start erl, you should be able to call functions from the re2 module:

$ erl
1> code:which(re2).
"/usr/lib/erlang/lib/re2/ebin/re2.beam"
2>

Advanced build time options

RE2 is automatically downloaded to c_src/re2 by the build script, and linked into the NIF lib. If you prefer to link against RE2 as found on the system, you can set the env var SYSTEM_RE2=1. If you do that and the library can not be found, it will fall back to a local copy (c_src/re2). Also, if you want to override the RE2 version that is fetched and built, when not using system RE2, you can do so by setting RE2_REV to a git rev.

By default, RE2 upstream source is fetched from the Google remote. If for some reason you need to fetch the upstream source from some other git repository, you can do so by setting the RE2_URL environment variable to a different git url.

Windows build

If you're trying to build on Windows, please make sure you have CMake and Visual Studio 2017. Before trying to build with rebar3, make sure rebar3, erlc, make, cmake are in the search path and that you've run Visual Studio's vcvars64.bat, or are inside the equivalent shell (spawned from the start menu entry). Windows builds are tested on Azure Pipelines (see CI badge).

License

Unless otherwise noted, the RE2 source files are distributed under the BSD-style license found in c_src/re2/LICENSE. The same license is used for the NIF library.