Interaction Trees

Interactions Trees (ITrees) are coinductive structures used to represent interactions between a system and its environment in the style of a process algebra. This repository contains a mechanisation of ITrees in Isabelle/HOL, for the purpose of verifying reactive systems and generating code for animation purposes. You can find a number of examples under examples/, and in particular the Haskell code can be executed in GHCi for animation purposes.

RoboChart

RoboChart theories and examples are under RoboChart and RoboChart/examples. There are also instructions and documents inside the folder. The latest development of RoboChart related theories is in the branch robochart_nondeterminism_resolving.

Installation

The theories have been developed in Isabelle2021-1. This instruction is based on Ubuntu/Linux. It would be similar on other operation systems.

Steps:

• Install GHC for Haskell, see here for details,
• Clone this repository, and
• use Isabelle/UTP distributions with prebuild heap images on Linux or Standard procedure to install Isabelle/HOL.

The prebuilt version comes with a patched Isabelle/HOL to have a console for animation, which is more convenient.

Clone this repository

1. Clone and enter the folder of this probabilistic relations

/path/to/yourfolder $ git clone https://github.com/isabelle-utp/interaction-trees.git
/path/to/yourfolder $ cd interaction-trees

We use /path/to/interaction-trees/ to denote the path to this particular directory.

Isabelle/UTP distributions with prebuild heap images on Linux

1. Download Isabelle/UTP distributions from here and choose Isabelle2021-1 on Linux (January 26th 2023), it is Isabelle2021-1-CyPhyAssure-20230126.tar.bz2 in this case
2. Uncompress it inside a folder, such as "/path/to/yourfolder":

/path/to/yourfolder $ tar -xvjf Isabelle2021-1-CyPhyAssure-20230126.tar.bz2
/path/to/yourfolder $ cd Isabelle2021-1-CyPhyAssure/

3. Launch Isabelle/UTP with session ITree_VCG

/path/to/yourfolder/Isabelle2021-1-CyPhyAssure/ $ ./bin/isabelle jedit -l ITree_VCG

Standard

1. Download Isabelle2021-1_linux.tar.gz from here.
2. Uncompress it inside a folder, such as "/path/to/yourfolder":

/path/to/yourfolder $ tar zxvf Isabelle2021-1_linux.tar.gz

3. Clone CyPhyAssure meta-repository (which is updated periodically to sync and try to keep in a stable state) from here and checkout all submodules

/path/to/yourfolder $ git clone https://github.com/isabelle-utp/CyPhyAssure.git
/path/to/yourfolder $ cd CyPhyAssure
/path/to/yourfolder/CyPhyAssure (main) $ git submodule update --init --recursive

4. Launch Isabelle/UTP with session ITree_VCG

/path/to/yourfolder $ ./Isabelle2021-1/bin/isabelle jedit -d CyPhyAssure -l ITree_VCG

Animation

With the prebuild version, animation would be simpler.

Prebuild-image

Load the theory for animation, then move your cursor to a line starting with animate, such as animate D_PatrolMod_p_sim to animate a definition D_PatrolMod_p_sim. When the cursor stops there, code generator starts to generate Haskell code, and compile. Usually, we will see below on the Output window.

See theory exports 
Compiling animation... 
See theory exports 
Start animation

Then click Start animation.

Standard

General steps are shown below. Please see instructions in each specific example for further considerations.

1. Open the main theory file for a model
2. Go to a line starting with command export_code, which exports generated Haskell code.
3. Click the Output window and you will see See theory exports, then double click the area theory exports, and now the exported code will be displayed on File Browser. Use File Browser to copy the generated files to the local physical file system, such as /path/to/simulation.
4. Go to a line starting with command export_generated_files, which exports two raw Haskell files simulation.hs and main.hs.
5. Click the Output window and you will see See theory exports, then double click the area theory exports, and now the two exported files will be displayed on File Browser. Use File Browser to copy the generated files to the local physical file system /path/to/simulation.
6. Open a terminal and cd to /path/to/simulation.

$ cd /path/to/simulation

7. Use GHCi for animation and load the main.hs, then run main.

$ ghci main.hs
*Main> main

8. Or use GHC to compile generated code, then run executable.

$ ghc -g main.hs
$ ./main