[butterisgood]

I start to want a Reader Monad stack for all the stuff I need to thread through all functions.

[charlieflowers]

Yeah, these kinds of "orthogonal" things that you want to set up "on the outside" and then have affect the "inner" code (like allocators, "io" in this case, and maybe also presence/absence of GC, etc.) all seem to cry out for something like Lisp dynamic variables.

[pjmlp]

A few languages have those, and I don't miss them, because in large codebases it becomes a pain to debug.

xBase, Clipper, Perl, Tcl upvars