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https://github.com/tofgarion/spark-by-example

SPARK by Example is an adaptation of ACSL by Example for SPARK 2014, a programming language which is a formally verified subset of Ada
https://github.com/tofgarion/spark-by-example

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SPARK by Example is an adaptation of ACSL by Example for SPARK 2014, a programming language which is a formally verified subset of Ada

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README 

        
* SPARK by Example



  SPARK by Example is a project (greatly) inspired by [[https://github.com/fraunhoferfokus/acsl-by-example][ACSL by Example]],

  a collection of verified C functions and data types from the C++

  standard library. SPARK by Example has two objectives



  - implement and verify the same functions as ACSL by Example using

    SPARK 2014 ([[https://www.adacore.com/about-spark][SPARK 2014]] is a formally verified subset of the Ada

    programming language)

  - highlight differences between verification of C programs and

    verification of SPARK programs



  Adacore has developed a great tutorial website for Ada/SPARK

  beginners [[https://learn.adacore.com/][here]]. It is recommended to follow at least the SPARK part

  of this tutorial before reading SPARK by Example.



** Tools used



   [[https://www.adacore.com/community][GNAT Community 2018]] has been used for this project. You may

   download and install it using the previous link.



** Table of contents



  1. [[./non-mutating/README.org][non mutating algorithms]]

  2. [[file:maxmin/README.org][maxmin algorithms]]

  3. [[file:binary-search/README.org][binary search algorithms]]

  4. [[file:mutating/README.org][mutating algorithms]]

  5. [[file:numeric/README.org][numeric algorithms]]

  6. [[file:heap/README.org][heap algorithms]]

  7. [[file:sorting/README.org][sorting algorithms]]

  8. [[file:classic-sorting/README.org][classic sorting algorithms]]



** Content of each directory and global Makefile



   Each directory corresponds to a chapter of ACSL by Example. Each

   directory contains a GNAT Project file (the file ending by ~.gpr~)

   containing informations about the location of the sources

   etc. Common configuration, e.g. GNATprove configuration, is

   specified in the ~spark_by_example_shared.gpr~ file at the project

   root.



   For each algorithm ~Algo~ to be proved, you will find the

   specification of ~Algo~ in the ~algo_p.ads~ file and its

   implementation if the ~algo_p.adb~ file. Specifications and

   implementations are defined in packages. To avoid name clashes with

   functions, packages names have a ~_P~ suffixes, hence the file

   names.



   Ghost functions that may be used in several algorithms are grouped

   in the ~spec~ directory at the root of the project. Lemmas used in

   proofs are grouped in the ~lemmas~ directory at the root of the

   project.



   A Makefile is provided for each chapter with some default values

   for provers timeouts, levels of proof etc. These default values are

   sufficient to prove the corresponding algorithms with the previous

   tools on a machine equipped with an Intel Core i7-4810MQ CPU and

   16GB of RAM. For each chapter, a ~all~ target proves all functions

   and procedures of the chapter. Each function or procedure has a

   corresponding target to prove it.



   The following variables can be used to control the behaviour of the

   Makefiles:



   - ~CHAPTER_NAME_DEFAULT_TIMEOUT~ (defined at the beginning of each

     Makefile) contains the default value for provers timeout

   - ~LEVEL_FUNCTION_NAME~ defines for each function the level used by

     ~GNATprove~

   - ~MEMCACHED=1~ enables the use of a [[https://www.memcached.org][Memcached]] server to cache

     proofs (it speeds up the proof process as some lemmas are used in

     several function for instance). Variables ~MEMCACHED_SERVER~ and

     ~MEMCACHED_PORT~ can be used to specify IP and port of server

     (~localhost:11211~ by default)

   - ~STATS=1~ enables the generation of statistics on the proof,

     based on the standard output. Generated files will be placed in

     the ~stats~ directory at the root of the project

   - ~PARALLEL~ controls the ~-j~ option of ~GNATprove~ for

     parallelizing proofs (default ~0~, use all cores of the machine)

   - ~DEBUG=1~ enables debug and verbose options of ~GNATprove~



   Other variables are available, see the ~Makefile-common~ file at

   the root of the project.



   For instance, if you want to prove all functions of chapter on

   non-mutating algorithms with statistics and by changing the default

   timeout to 10, issue the following command from the project root:



   #+BEGIN_SRC shell

     make -C non-mutating all STATS=1 NON_MUTATING_DEFAULT_TIMEOUT="TIMEOUT=10"

   #+END_SRC



   A Makefile is also available at the root of the project. It has a

   ~all-chapters~ target that proves all the chapters, gathers

   statistics, and generate a ~recap.csv~ file in the ~stats~

   directory.



   For instance, if you want to prove all chapters with statistics and

   Memcached, issue the following command:



   #+BEGIN_SRC shell

     make all-chapters STATS=1 MEMCACHED=1

   #+END_SRC



** Contributing



   If you want to contribute to SPARK by Example, please read the

   [[./CONTRIBUTING.org][CONTRIBUTING]] file.



** References



  - [[http://docs.adacore.com/spark2014-docs/html/ug/index.html][SPARK 2014 user guide 19.0]]

  - [[https://learn.adacore.com/][learn.adacore.com]]



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