The sh function was originally included in the duct library itself.
Because of safety concerns, we decided to split that function into sh
(taking only static strings) and sh_dangerous (taking any string). That in
turn raised a portability problem: duct is a
multi-language library, and most
languages can't distinguish string lifetimes the way that Rust can. As an
experiment, we're splitting these functions into their own crate, with the
intention of keeping them Rust-only.
I don't know if we'll keep this arrangement, but here are some other points in favor:
- Simple
shcommands are nice when you first write them, but it feels annoying to rewrite them ascmd!once you need to introduce a variable somewhere. That annoyance is pressure to do something evil. - Legitimate use cases for
sh_dangerousin small scripts is rare. The common use case is something like a build tool, where the user is expected to run arbitrary shell commands through the tool. Importing an extra crate (or just copying the whole function) is less of a big deal in the source code of a build tool than it is in a small script. - Many languages have standard library support for launching shell commands.
Rust doesn't, and so
duct_shis more valuable in Rust than it would by in say Python.