Explore categorising variables & parameters

[sandcha]

We received the following email asking for categories in legislation explorer:

je souhaite effectuer des tests avec openfisca. J'ai bien réussi à l'installer et à exécuter des tests mais je trouve qu'il est difficile de si retrouver dans les variables et paramètres (https://fr.openfisca.org/legislation/#search-input) car ils sont triées pas ordre alphabétique. Est-ce qu'il existe une version où ils seraient classés par catégories? Par exemple:

• individus: salaire_net, salaire_brut, exonere_taxe_habitation...
• entreprise: ...

Possible solutions:

1. Check Models section in swagger for variables linked to specific entity
2. Improve search bar with entity: individu to find all variables linked to individu entity
3. Link file path in a variable or parameter description e.g. revenus/activite/ for openfisca_france/model/revenus/activite/salarie.py
4. ...

This could be implemented:
a. In OpenFisca Web API (Legislation Explorer would be updated to read it)
b. In Legislation Explorer
c. ...

[MattiSG]

To me #80 should first be implemented to see if this is still legit afterwards.

[Morendil]

I second the need, I find it very annoying that the Explorer provides so little structure when visually scanning with a desired result among many.

A caution however is that the design space is quite large. We might want to distinguish variables, entities and parameters; we might want to tag variables and parameters with additional categorization data, and show these tags; we might want to provide a "browse" entry point indexed by categories, or search filters, or… To weigh among the many options by cost/benefit I think it would be wise to cheaply investigates various options with some user research, @renardpal can help here.

[benjello]

I always supported parameters and variables are very different.

The important point about variables is how they are related to other variables in the system. So being able to travel through the network of variables depending or that depend on a chosen variable is crucial.