  Variable environment is the time-honored way of making sense of free
variables, used in programming language theory as well when writing
interpreters and some compilers. Algebraic effects give another way, as was
pointed already at HOPE 2017. Although a theoretical curiosity, it may have
surprising practical benefits: a new way of writing compilers, with the
incremental type-checking, with easy variable usage, leaf function analyses.
This work-in-progress report prototypes and illustrates the idea.
