How cmdargs subverts Haskell

[atravers]

[…] cmdargs subverts Haskell

…more or less than the examples presented here e.g:

tomjaguarpaw:

At work we have a Nix-based build system. It “should be” pure, since Nix is reproducible. However, it sometimes calls out to external hardware which is transiently broken, caching “hardware did not respond” into our build results, and with no way of purging it.

Alternately, is it more or less “subversive” than GHC’s internal UniqSupply type:

(lines 123-135)

We [had] to rely on -fno-state-hack, full laziness and inlining to get the same
result. It was very brittle and required enabling -fno-state-hack globally. So
it has been rewritten using lower level constructs to explicitly state what we
want.

…if it is, you could be in good company:

[my] bad_ctx example has the same kernel of badness as the unique-supply tree example in Sec 10.2 of [Launchbury and Peyton Jones’s] paper.

Breaking referential transparency with unsafeInterleaveST, Oleg Kiselyov.

To me at least, the approach used in cmdargs seems more a case of “incurring technical debt” to avoid having to use the lumbering monadic IO type in a lot more places, rather than being “subversive”.