So somehow this paper misses one of the greatest developments in this area, oil https://www.oilshell.org/ - which:

1. has a compatibility mode with sh and bash. it's the only new shell I know with a upgrade path from bash [0]

2. otherwise fixes tons of unix shell misfeatures and in particular fixes quoting hell [2]

PS: one fun quirk of the oil implementation is that it's written in Python.. but actually in a DSL that generates statically typed C++ code, ditching the Python runtime altogether [3] [4] - when you do compile Oil, you just get a C++ tarball (somewhat like fftw, a FFT package written in OCaml but which generates C code; fftw developers write OCaml, but fftw users compile C)

[0] https://www.oilshell.org/why.html

[1] https://www.oilshell.org/blog/2020/01/simplest-explanation.h...

[2] https://www.oilshell.org/release/latest/doc/idioms.html

[3] https://www.oilshell.org/blog/2021/01/why-a-new-shell.html#w...

[4] But actually I think there's still work to do to remove the CPython dependency at runtime, https://github.com/oilshell/oil/issues/636