A simple DSL that lets our users easily get some work done by calling into a library of functions. DSLs are powerful tools. They’re another way we can be creative and solve problems that make it easier for our users to get work done. From the user’s perspective, they’re just running “commands.” From our perspective, we get to leverage Python’s dynamic nature and its features and, in turn, reap the rewards of having all of the power of Python and its ecosystem available to us. For example, we can easily make changes to a library module or extend the library with new modules to expose new functionality using the standard library or 3rd party packages.
The following techniques were used to create this DSL:
- importlib.import_module(): dynamically import a module at runtime
- getattr(): get an object’s attribute/function (-> reflection)
- variable-length function arguments and keyword arguments (*args, **kwargs)
- converting a string to a different type
Python 3 needs to be installed.
# get help:
python dsl.py help=module
# run dsl script file:
python dsl.py src.dsl
A user has to specify the following to execute commands of our DSL:
- module name
- function name
- parameters, separated by whitespaces
see src.dsl as an example
inspired by Dan Bader's blog