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Solver for higher-order functional programs
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Inox Build Status

Inox is a solver for higher-order functional programs which provides first-class support for features such as:

  • Recursive and first-class functions
  • ADTs, integers, bitvectors, strings, set-multiset-map abstractions
  • Quantifiers
  • ADT invariants
  • Dependent types

Interfacing with the solver can take place through the Scala API by constructing the AST corresponding to the query of interest and then feeding it to one of the solvers. For more information, see:

  • The usage tutorial gives some insight on how to use Inox as a library.
  • The tree interpolators provide easy tree construction/extraction for library use.
  • A more detailed description of the available solver/evaluator API calls.
  • A description of the trees API and how to extend them.

To import Inox into your project, add the following lines to your build.sbt:

resolvers += "Sonatype OSS Releases" at ""
resolvers += "uuverifiers" at ""
libraryDependencies += "ch.epfl.lara" %% "inox" % "1.0.2"

Alternatively, one can use Inox through command-line by using the TIP format to describe the relevant query. The easiest way to use the Inox command line is to simply build the project and use the generated script.

Solver Backends

Inox relies on SMT solvers to solve the constraints it generates. Inox ships with the JVM SMT solver Princess which should work out of the box on any system.

You can also use the following external SMT solvers:

Solver binaries that you install should match your operating system and your architecture. We recommend that you install these solvers as a binary and have their binaries available in the $PATH (as z3 or cvc4). Once they are installed, you can instruct Inox to use a given sequence of solvers. The more solvers you have installed, the more successful Inox might get, because solver capabilities are incomparable.

Native Z3 API

In addition to these external binaries, a native Z3 API for Linux is bundled with Inox and should work out of the box (although having an external Z3 binary is a good idea in any case). If you build yourself, the generated script should put the native API onto your classpath. Otherwise, you will have to make sure the relevant jar from "unmanaged" is on your runtime classpath.

For other platforms than Linux, you will have to recompile the native Z3 communication layer yourself; see ScalaZ3 repository for information about how to build and package the project. You will then need to copy the resulting jar into the "unmanaged" directory named "scalaz3-$os-$arch-$scalaBinaryVersion.jar" (replace the $ variables by the relevant values).

Solver Defaults

As of now the default solver is the native Z3 API. If that solver is unavailable, a series of fallbacks take place until the princess solver. You can specify which solver to use by e.g. giving the option --solvers=smt-cvc4 to use CVC4. Check the --solvers line in Inox' help.

Building Inox

Inox is probably easiest to build on Linux-like platforms, but read on regarding other platforms.

Due to its nature, this documentation section may not always be up to date; we welcome pull requests with carefully written and tested improvements to the information below.


Linux & Mac OS-X

Get the sources of Inox by cloning the official Inox repository:

$ git clone
Cloning into 'inox'...
// ...
$ cd inox
$ sbt clean compile
// takes about 1 minutes

Inox compilation generates an inox bash script that runs Inox with all the appropriate settings. This script expects argument files in the TIP input format and will report SAT or UNSAT to the specified properties.

See ./inox --help for more information about script usage.


Not yet tested!

You will need a Git shell for windows, e.g. Git for Windows. Building then proceeds as described above.

You will then need to either port the bash inox script to Windows, or run it under Cygwin.

You may be able to obtain additional tips on getting Inox to work on Windows from Mikael Mayer or on his dedicated web page.

Running Tests

Inox comes with a test suite. Consider running the following commands to invoke different test suites:

$ sbt test
$ sbt it:test
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