Initial commit

.gitignore

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+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+pip-wheel-metadata/
+share/python-wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.nox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*.cover
+*.py,cover
+.hypothesis/
+.pytest_cache/
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+db.sqlite3-journal
+
+# Flask stuff:
+instance/
+.webassets-cache
+
+# Scrapy stuff:
+.scrapy
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# pyenv
+.python-version
+
+# pipenv
+#   According to pypa/pipenv#598, it is recommended to include Pipfile.lock in version control.
+#   However, in case of collaboration, if having platform-specific dependencies or dependencies
+#   having no cross-platform support, pipenv may install dependencies that don't work, or not
+#   install all needed dependencies.
+#Pipfile.lock
+
+# PEP 582; used by e.g. github.com/David-OConnor/pyflow
+__pypackages__/
+
+# Celery stuff
+celerybeat-schedule
+celerybeat.pid
+
+# SageMath parsed files
+*.sage.py
+
+# Environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
+
+# Spyder project settings
+.spyderproject
+.spyproject
+
+# Rope project settings
+.ropeproject
+
+# mkdocs documentation
+/site
+
+# mypy
+.mypy_cache/
+.dmypy.json
+dmypy.json
+
+# Pyre type checker
+.pyre/

README.md

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+# GAMBA tools
+
+The `gambatools` package is a Python 3 package that aims to
+support education in theoretical computer science at
+[Eindhoven University of Technology](https://www.tue.nl/en/).
+It contains a library for
+DFAs, NFAs, PDAs, Turing machines, context free grammars and
+regular expressions. Moreover, the package provides Jupyter notebooks with
+exercises. The library has been developed by Wieger Wesselink,
+and it was designed together with Erik de Vink.
+
+# GAMBA
+The code was developed as part of the GAMBA project, which stands for:
+*Grammars and Automata Made Boffo and Assessible*. The goals of the project are
+to support
+
+* practising and assessing formal language techniques
+* self-paced learning outside contact hours
+* immediate feedback while practising
+* automated grading for assessment 
+
+(*boffo*: extremely successful, sensational)
+
+# License
+The code is distributed under the `GPL-3.0-or-later` license.
+
+# Installation
+The package can be installed using
+```
+pip install gambatools
+```
+The required python packages can be found in `requirements.txt`.
+
+# Rendering images
+For visualization the [graphviz](https://pypi.org/project/graphviz/) python
+package is used. **To render the generated DOT source code, you also need to install
+Graphviz**. See the [Graphviz website](https://graphviz.org/) for further instructions.
+Make sure that the directory containing the `dot` executable is on your systems’ path. 
+
+# Documentation
+The file `doc/specifications.pdf` contains formal specifications
+of the algorithms in the library. Note that the code maps almost one-to-one
+to the specifications, so in order to understand the code please consult the
+pseudocode specifications.
+
+# Notebooks
+The directory `notebooks` contains a number of Jupyter notebooks
+with exercises. In `notebooks/with-answers` the correct answers are
+already given, while in `notebooks/without-answers` they have been
+left out. 
+The answers to the exercises are checked automatically.
+Whenever the user makes a mistake, appropriate feedback is given.
+
+![NFA to DFA](doc/images/nfa2dfa.png)
+
+For specifying a DFA, NFA, etc. a line based textual input format is used,
+see the example below. The documentation contains a section that describes
+the syntax, while in the `examples` directory a number of examples can be found.
+```
+input_symbols 0 1
+states qA qB qC qD
+
+initial qA
+final qC
+
+qA qB 0
+qA qD 1
+qB qB 0
+qB qC 1
+qC qB 0
+qC qC 1
+qD qD 0
+qD qD 1
+```
+
+# Notebook generation
+For convenience there is a mechanism to automatically generate notebooks from
+templates.
+The notebooks in `notebooks/with-answers` and `notebooks/without-answers`
+have been generated using the commands
+```
+make_notebook.py -o without-answers notebooks.batch
+make_notebook.py --with-answers -o with-answers notebooks.batch
+```
+The templates contain tags of the form `<<tag>>` that are substituted by
+the `make_notebook.py` script. This generation is still experimental, and
+there is currently no documentation available for this.
+
+# Contact
+If you are interested in using the package for education or have questions
+or feedback, the authors can be reached by email:
+<[email protected]> or <[email protected]>.

examples/cfg1.cfg

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+%% language = \lbrace \, a^{\mkern1mu n} \mkern1mu b^{\mkern1mu m} c^{\mkern1mu \ell} \mid n = m \lor m = \ell \lor n = \ell \, \rbrace
+%% accepted = _ aaa bb c aabb bc aabc aabbbcc aaaccc
+%% rejected = bcc aab aabbbc ccaaabb bbccaa abab cb aaacccc
+%% question = Give a CFG that generates the language $@language@$.
+
+S -> XC | AY | Z
+X -> aXb | ε
+Y -> bYc | ε
+Z -> aZc | B
+A -> aA | ε
+B -> bB | ε
+C -> cC | ε

examples/cfg2.cfg

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+S -> ASA | aB
+A -> B | S
+B -> b | ε

examples/chomsky1.cfg

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+T -> AC | AS | SA | DB | a
+S -> AS | SA | DB | a | AC
+B -> b
+A -> AC | AS | SA | DB | a | b
+C -> SA
+D -> a

examples/complement.dfa

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+%% language = \{ \, w \in \{a,b\}^\ast \mid \#_a(w) \geqslant 2 \, \}
+
+input_symbols a b
+states q0 q1 q2
+initial q0
+final q2
+q0 q0 b
+q0 q1 a
+q1 q1 b
+q1 q2 a
+q2 q2 a b

examples/dfa1.dfa

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+%% Sipser Exercise 1.6a
+%% 0.(0+1)*.1
+
+%% question = Give a DFA that generates the language $@language@$.
+%% language = \{ w \in {0,1}^\ast \mid w \text{ starts with } 0 \text{ and ends with } 1 \}
+
+%% selected_word = 0101
+
+input_symbols 0 1
+states qA qB qC qD
+
+initial qA
+final qC
+
+qA qB 0
+qA qD 1
+qB qB 0
+qB qC 1
+qC qB 0
+qC qC 1
+qD qD 0
+qD qD 1
+

examples/dfa2.dfa

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+%% alphabet = \{a,b\}
+
+initial q0
+final q1
+q0 q1 a
+q1 q1 a b
+q0 q2 b
+q2 q2 a b

examples/intersection1.dfa

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+%% language = \{ \, w \in \{a,b\}^\ast \mid \mbox{$\#_a(w)$ even} \, \}
+
+input_symbols a b
+states q0 q1
+initial q0
+final q0
+q0 q0 b
+q0 q1 a
+q1 q0 a
+q1 q1 b

examples/intersection2.dfa

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+%% language = \{ \, w \in \{a,b\}^\ast \mid \#_b(w) \geqslant 2 \, \}
+
+input_symbols a b
+states q0 q1 q2
+initial q0
+final q2
+q0 q0 a
+q0 q1 b
+q1 q1 a
+q1 q2 b
+q2 q2 a b

examples/nfa1.nfa

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+%% language = \{ w \in \{0,1\}^* \mid \#_0(w) \geq 2, \#_1(w) \leq 1 \}^*
+%% question = Give an NFA that accepts the language $@language@$.
+
+initial s6
+final s2 s5 s6
+s0 s1 0
+s0 s3 1
+s1 s2 0
+s1 s4 1
+s2 s0 ε
+s2 s2 0
+s2 s5 1
+s3 s4 0
+s4 s5 0
+s5 s0 ε
+s5 s5 0
+s6 s0 ε

examples/nfa2.nfa

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+%% question = Give the DFA obtained from the given NFA using the NFA to DFA procedure. Use set notation like `{q0,q1}` (without spaces) for the states in the DFA.
+
+input_symbols a b
+initial q0
+final q2
+q0 q0 a b
+q0 q1 ε
+q1 q1 a
+q1 q2 b

examples/pda-simple.pda

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+%% language = \{ \, a^{\mkern1mu n} b^{\mkern1mu n} \mid n \geqslant 0 \, \}
+%% question = Give a PDA that accepts the language $@language@$.
+
+initial q0
+final q3
+
+q0 q1 e,e$
+q1 q1 a,eX
+q1 q2 e,ee
+q2 q2 b,Xe
+q2 q3 e,$e 

examples/pda1.pda

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+%% language = \{ w \in \{a,b\}^\ast \mid \#_a(w) = 2\#_b(w) \}
+%% question = Give a PDA that generates the language $@language@$.
+
+initial q0
+final q6
+q0 q1 ε,ε$
+q1 q2 ε,$$
+q1 q3 ε,$$
+q1 q6 ε,$ε
+q2 q1 ε,$$
+q2 q2 a,nε
+q2 q5 b,εn
+q3 q1 ε,$$
+q3 q3 a,εp
+q3 q4 b,pε
+q4 q3 ε,pε
+q4 q5 ε,$$
+q5 q2 ε,εn

examples/pda2.pda

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+%% language = \{ w \in \{a,b\}^\ast \mid \#_a(w) = 2\#_b(w) \}
+%% question = Give a PDA that generates the language $@language@$.
+
+epsilon ε
+initial q0
+final q6
+q0 q1 ε,ε$
+q1 q2 ε,$$
+q1 q3 ε,$$
+q1 q6 ε,$ε
+q2 q1 ε,$$
+q2 q2 a,nε
+q2 q5 b,εn
+q3 q1 ε,$$
+q3 q3 a,εp
+q3 q4 b,pε
+q4 q3 ε,pε
+q4 q5 ε,$$
+q5 q2 ε,εn