Starship has an advanced, experimental feature where fancy stuff in the
prompt can be replaced with something more simple after the command is
ran. This is very helpful for copy and pasting shell history somewhere
else.
docs: https://starship.rs/advanced-config/#transientprompt-and-transientrightprompt-in-fish
Fish is currently the only shell as far as I can tell that both
home-manager and starship support for this feature. Since the function
has to be called after starship is loaded, this seems like the best
place to put it.
format
The code that is being evaled without the `--print-full-init` flag is
this:
```sh
__main() {
local major="${BASH_VERSINFO[0]}"
local minor="${BASH_VERSINFO[1]}"
if ((major > 4)) || { ((major == 4)) && ((minor >= 1)); }; then
source <(/nix/store/...-starship-1.3.0/bin/starship init bash --print-full-init)
else
source /dev/stdin <<<"$(/nix/store/...-starship-1.3.0/bin/starship init bash --print-full-init)"
fi
}
__main
unset -f __main
```
This code checks for bash version >= 4.1 , which has been released in
2009. Since this version is widely unavailable in nixpkgs, we can skip
one program invocation and directly call `starship init bash
--print-full-init`.
Currently, dot directories and XDG base directories are used
inconsistently in the Home Manager option declarations. This creates
ambiguity for the user as to where the location of the file should be
albeit this is rarely encountered in practice as it is sufficient to
read upstream documentation. The rationale is to make declarations
consistent and make a clear distinction between hardcoded and modular
specifications.
References to ~/.config in relevant nixpkgs modules were untouched as
the location is hardcoded upstream[1]. Furthermore, modules of
programs which do not follow XDG specifications were also untouched.
Generalization of tilde(~) expansions to $HOME were also considered,
however there isn't sufficient rationale despite the use of $HOME
being more universal. The expansion is standardized in POSIX[2] and is
essentially portable across all shells, thus there is no pragmatic
value to introducing the change.
[1] https://github.com/nixos/nixpkgs/blob/master/pkgs/top-level/impure.nix
[2] https://pubs.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_01
The previous fish integration for starship erroneously used parts of
POSIX-esque test syntax. It also used `-n` instead of `-z` to check
for an unset variable.
PR #1422
