As it stands, Gen programs draw random bits from the global entropy store. Going forward some control over the random seed is required --- for debugging, reproduciblity, and independence of Gen code from other libraries.

The granularity of entropy control is a design choice. Some possibilities include:

1. Continue using global seed which is set using Random.seed!(n)
   • pros: approach requiring least work
   • cons: unpredictable, no separation, harder to reproduce/debug results.
2. Furnish each Gen method that makes random choices with an (optional) a formal parameter prng
   • pros: composes easily, reproducible, predictable, modular, adds minimal API complexity, each random procedure becomes deterministic given its inputs.
   • cons: needs implementation and design
3. Design a special Monadic construct for the RandomSeed
   • pros: potentially more transparent to the user / designer of Gen library
   • cons: Julia does not have good native support for Monadic computation
4. Design a single global entropy source for Gen only
   • pros: less complex than 2 and 3, separates Gen from other libraries.
   • cons: less modular, and should check if/how to implement such an object in Julia.