exercism fetch python dot-dsl


Write a Domain Specific Language similar to the Graphviz dot language.

A Domain Specific Language (DSL) is a small language optimized for a specific domain.

For example the dot language of Graphviz allows you to write a textual description of a graph which is then transformed into a picture by one of the graphviz tools (such as dot). A simple graph looks like this:

graph {
    graph [bgcolor="yellow"]
    a [color="red"]
    b [color="blue"]
    a -- b [color="green"]

Putting this in a file example.dot and running dot example.dot -T png -o example.png creates an image example.png with red and blue circle connected by a green line on a yellow background.

Create a DSL similar to the dot language.

Description of DSL

A graph, in this DSL, is an object of type Graph, taking a list of one or more

described as tuples.

The implementations of Node and Edge provided in dot_dsl.py.

Observe the test cases in dot_dsl_test.py to understand the DSL's design.

Exception messages

Sometimes it is necessary to raise an exception. When you do this, you should include a meaningful error message to indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. Not every exercise will require you to raise an exception, but for those that do, the tests will only pass if you include a message.

To raise a message with an exception, just write it as an argument to the exception type. For example, instead of raise Exception, you should write:

raise Exception("Meaningful message indicating the source of the error")

Running the tests

To run the tests, run the appropriate command below (why they are different):

Alternatively, you can tell Python to run the pytest module (allowing the same command to be used regardless of Python version): python -m pytest dot_dsl_test.py

Common pytest options

For other options, see python -m pytest -h

Submitting Exercises

Note that, when trying to submit an exercise, make sure the solution is in the $EXERCISM_WORKSPACE/python/dot-dsl directory.

You can find your Exercism workspace by running exercism debug and looking for the line that starts with Workspace.

For more detailed information about running tests, code style and linting, please see the help page.

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.