No, unlike workflow managers such as Snakemake and Nextflow, Morloc does not offer function-specific environments. This is a deliberate design choice.

Dependency resolution is a hard and heavily researched problem. The general goal of dependency solvers is to find one set of dependencies that satisfies the entire program. The bioinformatics community often gives up on finding unified environments and instead runs each function in its independent environment. With every function running in its own container, all dependency issues are encapsulated and all functions may be executed from one manager. But this comes at a heavy cost. Each application must be wrapped in a script, the script must be executed via an expensive system call into the container, and data must be serialized and sent to the container. This approach is reasonable for workflows with a small number of heavy components. But from a programming language perspective, wrapping every function call in its own environment is inefficient and opaque.

Morloc is designed not to hide problems in boxes, but rather to solve the root problem. Conventional workflow languages attempt to simplify workflows design by layering frameworks over the functions. The Morloc approach is the exact opposite. First delete everything unnecessary from all applications and lift their light algorithmic cores into clean, well-typed libraries. Then build upwards through composition of these pure functions—​and judicious use of impure ones—​to create efficient, reliable, and composable tools.

Now, if you really do need to run something in a container, you can just make a function that wraps a call to a container and then use it just as you would any other function. You could even write a wrapper function that takes a record with all the metadata needed for a conda environment and execute its function within that environment. We can do this through libraries, so there is no need to hardcode this pattern into the Morloc language itself.

The reproducibility of Morloc workflows may be ensured by running the entire Morloc program in an environment or container, with a single set of dependencies. The specific Morloc compiler version can be specified and modules may be imported using their git hashes. This is done in the current Morloc examples (see the Dockerfile in the workflow-comparisons folder of https://github.com/morloc-project/examples).