ACF : Analyse et Conception Formelles
"Software Formal Analysis and Design"
- Subjects: functional
programming, first order logic, formal specification and formal
proof assistant and counter-example finders and the
This course is
about using formal methods to design verified
software components. To
tackle this goal we rely on functional programming, first order logic
for specifying properties, proof assistant for property checking on
programs and the Scala programming language for integrating the
verified components into a Java application. With regards to
verification, we study and use the powerful proof
the Isabelle/HOL proof assistant. For code generation, we use the
awesome Scala code exportation feature of Isabelle/HOL.
final achievement is a verified Scala component achieving
price negociation in a web application. The component is designed and
verified in Isabelle/HOL. Then, the functional code is exported to
and integrated in the Java (web) application.
Disclaimer: this is a course on formal
software design and not on proof design. Thus, students are
given a limited set of proof tactics that is not sufficient to prove
complex properties. As a result, properties of last lab sessions are
generally not proven but only checked using Isabelle/HOL powerful
The course consists of 7 lectures and 11 lab sessions. Lecture
(cm1.pdf to cm7.pdf) are (almost) in english, the lab notes
(tp0.pdf to tp8-10.pdf) are in french. The Isabelle/HOL survival
kit gives an
idea of the used subset of
Isabelle commands. Lectures contains exercises that were solved on
Isabelle/HOL by students on my computer (and projected) during the
lecture. Students are also given a small (well as focused as possible
on the course objective) bibliography
schedule is the following:
: teasing... a simple Java lab session
... to show that designing a (simple) software can be very error prone.
It is nearly impossible to directly come up with the correct program
for this (refined) simple list inclusion test, either in imperative or
in recursive style. The objective is to motivate the fact that defining
the expected properties is crucial to detect problems and, in the end,
be sure that the solution is correct. An (opaque) Java oracle is given to the students to test
their code and know how far their program is from the
solution. An overall of 5% students ended up with the correct program
within 2 hours.
- intro.pdf : overall objectives and
organization of the course.
- cm1.pdf : propositional and first
order logic, interpretations and models in Isabelle/HOL
- cm2.pdf, initial
theory for the course cm2.thy
: terms, functions,
lambda-calculs and types (export_code to Scala).
- tp1.pdf, initial
theory for the lab session tp1.thy
: first lab on
Isabelle/HOL: propositional and first order logic (auto+nitpick).
Plus additional exercises for those who are familiar with sequent
calculus: tp1bis.thy and Defs.thy
- cm3.pdf, initial
theory for the course cm3.thy
: recursive functions (fun,
- cm4.pdf, initial
theory for the course cm4.thy : basic proof tactics (auto,
nitpick, quickcheck). Students
interested by a deeper presentation of the proof assistant can
have a look at the Isabelle/HOL tutorial in
the short Isabelle/HOL bibliography.
We also provide two Isabelle/HOL files LOG.thy
and Defs.thy if you are interested in using
deduction rules in Isabelle/HOL. Those who are more familiar
calculus should get by, by replacing introduction/elimination by
the adapted left/right annotation :-).
- tp2.pdf : (lab sessions 2 and 3):
recursive functions and basic proof tactics. Defining and proving usual
boolean operations on sets implemented as lists. We also provide an
other exercise which is a simple theory
file in which the 4 main lemmas admit counterexamples. Some
of the lemmas need some fine tuning of Nitpick and Quickcheck for
the counterexamples to be found: this is the purpose of this
- cm5.pdf Scala Crash Course. Basics
of Scala, functional programming in Scala, object model, case
classes, pattern-matching and interoperability with Java. Deeper
informations on the language are available
from M. Odersky, L. Spoon and
B. Venners online
book and from those selected documents.
- tp4.pdf : lab on Scala.
an evaluator and a pretty printer for a simple imperative language...
using pattern matching to avoid using the visitor design pattern. We
start from the following Eclipse
project. Integrate the (certified) implementation of set
operations (done in lab sessions 2 and 3) to perform automated testing of other (bugged)
implementations, available in this eclipse project.
- cm6.pdf, initial
theory for the course cm6.thy
: certified programming and
existing certified programming
- tp5.pdf, TP5ACF.zip, tp5.thy
: they redo tp0.pdf but with
Isabelle/HOL and Scala code export. They use the same Java oracle to
solution. An overall of 50% students ended up with the correct program
within 2 hours.
- cm7.pdf, initial
theory for the course cm7.thy
: software verification techniques.
- tp67.pdf, tp67.thy,
TP67ACF.zip : they design a static
analyser for a simple toy language, define the correctness theorem to
guarantee the safety of the analyzer, define the completeness theorem
to refine it (using the counterexamples). Integrated with a Scala
parser for the toy language.
- tp8-10.pdf, tp8-10.thy,
TP8-10ACF.zip : they design a validation
tool for a price negociation web application. A merchant and a client
send messages to the validation tool to negociate a price. A price is
validated if a price proposed by a client is superior or equal to a
price proposed by the merchant. In the end, the list of validated
should be correct. As with all protocols, more complex than it seems at
first glance. They define the functions, check the 8 properties and
export the Scala code. All the validations tools of all students are
then deployed on a web site so that all students can attack all
validation tools and report on the attacks found.
- We use Isabelle/HOL
Then, if you plan to use Isabelle/HOL
for all lab sessions, you
will have to install and configure a few things:
- To have a full quickcheck (with narrowing): install the Gnu
Haskell Compiler and in the file $ISABELLE_HOME/etc/settings, set the
ISABELLE_GHC variable to the path where the binaries of the compile
(i.e. the command ghc) is installed
- To use Z3 with sledgehammer, set the Isabelle system option
"z3_non_commercial" to "yes" (e.g. via the Isabelle/jEdit menu
Plugin Options / Isabelle / General).
- To have a full sledgehammer under linux: install libwww
- ScalaIDE4.3, or an eclipse 4.4
(Luna) with Scala 2.11 pluggin. More recent versions of ScalaIDE will not be
compatible with the course material we provide.
Many thanks to
people of the Isabelle/HOL team at TUM: Tobias Nipkow, Jasmin
Blanchette, Lukas Bulwahn, Florian Haftmann and Alexander Krauss for answering questions
and for fruitful discussions.
Many thanks to Olivier Barais, Sandrine Blazy, Benoît
Combemale, Arnaud Jobin, Julien
Richard-Foy and Gweltaz Riou for
their help during the preparation of this course.