I am doing Bayesian inference in the parameters of a fairly complex physical model. The model is specified by the user in a (YAML) configuration file. That file is loaded and translated into Julia code by a routine I wrote. The user-generate Julia code is all contained within a module, which includes all routines necessary to do inference (therefore to computer the likelihood, the prior and so on), together with user-set parameters and external data. The user-set parameters and external data are stored in the module as global variables.