The following snippet for .julia/config/startup.jl implements directory, user, and host tracking for julia-repl.
# set up emacs directory, host, and user tracking for julia-repl
atreplinit() do repl
if haskey(ENV, "INSIDE_EMACS") &&
occursin(r",term:", ENV["INSIDE_EMACS"])
# acquire REPL
@eval import REPL
# only initialize repl.interface if necessary
if ! isdefined(repl, :interface)
repl.interface = REPL.setup_interface(repl)
end
# install a new prompt_prefix
repl.interface.modes[1].prompt_prefix =
((old, user, host, cwd) ->
(() ->
((ENV["LOGNAME"] != user ?
"\033AnSiTu "*(user = ENV["LOGNAME"])*"\n" : "") *
(gethostname() != host ?
"\033AnSiTh "*(host = gethostname())*"\n" : "") *
(pwd() != cwd ?
"\033AnSiTc "*(cwd = pwd())*"\n" : "") *
(isa(old, String) ? old : old()))))(
repl.interface.modes[1].prompt_prefix, "", "", ""
)
end
end
# end of set up emacs directory, host, and user tracking for julia-repl
It’s restricted to julia-repl by the test for occursin(r",term:", ENV["INSIDE_EMACS"], and it’s careful not to overwrite any previous modifications to repl.interface or prompt_prefix, but it won’t pick up subsequent changes to the color of the julia> prompt, and it’s vulnerable to some subsequent snippet blindly reinitializing repl.interface.
It’s been tested only on linux and mostly on recent versions of julia, I’m curious if it’s more generally useful.