Introduction

Choixe is a mini-language built on top of python that adds some cool features to markup configuration files, with the intent of increasing code reusability and automatizing some aspects of writing configuration files.

  • Variables: placeholders for something that will be defined later.

  • Imports: append the content of another configuration file anywhere.

  • Sweeps: exhaustive search over a parameter space.

  • Python Instances: calling of dynamically imported python functions.

  • Loops: foreach-like control that iterates over a collection of elements.

  • Utilities: like generating a random uuid or getting the current datetime.

Currently supported formats include:

  • YAML

  • JSON

Note that any markup format that can be deserialized into python built-ins can work with Choixe syntax. In fact, you can use these features even with no configuration file at all, by just putting some directives into a plain python dictionary or list, Choixe does not care.

All that Choixe does is the following:

   flowchart LR
   A[File]
   B[Python\nStructure]
   C[Parsed\nChoixe AST]
   D[Python\nStructure]
   E[File]
   A -.->|Loading| B
   B -->|Parsing| C
   C -->|Processing| D
   D -.->|Writing| E

  1. Optionally load a structure from a markup file. The structure usually consists of nested python dictionaries or lists, containing built-in types like integers, floats, booleans, strings.

  2. Parse the structure into an AST, looking for a special syntactic pattern - called “directive” - in every string that is found.

  3. Process the AST by visiting it recursively, resulting in a another python structure.

  4. Optionally write the new structure to a markup file.

For simplicity, in the rest of this tutorial most examples will be written in YAML, as it is less verbose than JSON or python syntax.