Grandparent has a point, and it's not quite as outlandish as you make it out to be.
Consider that a lot of Python developers write most of their code in Python, then rewrite critical parts in C to speed it up. Python is not a speed demon, and that becomes particularly problematic with tight loops or heavy math—but writing entire applications in C is error-prone and tedious.
Rust won't outright replace both of those, but it does offer a nice middle ground: it's safe, it has some higher-level constructs, it does away with some boilerplate, it builds fairly easily, and it still compiles essentially to machine code. Writing quick shell-like scripts or entire applications in a systems language is now a viable option for lazy jerks like me, even if it's not always the best one.
> Writing quick shell-like scripts or entire applications in a systems language is now a viable option for lazy jerks like me, even if it's not always the best one.
I agree completely. I love Rust for this reason too. That's not what the grandparent said, or what I'm arguing against.
Grandparent was dismissing my concern about language interoperability because new languages should cover "all your needs." This attitude is closed-minded and dangerous.
A language that covers lots of needs is great. A language that is so useful that you find yourself needing fewer total languages for your project is great.
But the moment you use that as a reason to stop caring about interoperability between languages, to argue that it doesn't matter whether your language can interface with others, that's the moment when I stop paying attention to what you are designing.
Consider that a lot of Python developers write most of their code in Python, then rewrite critical parts in C to speed it up. Python is not a speed demon, and that becomes particularly problematic with tight loops or heavy math—but writing entire applications in C is error-prone and tedious.
Rust won't outright replace both of those, but it does offer a nice middle ground: it's safe, it has some higher-level constructs, it does away with some boilerplate, it builds fairly easily, and it still compiles essentially to machine code. Writing quick shell-like scripts or entire applications in a systems language is now a viable option for lazy jerks like me, even if it's not always the best one.