import Darwin

var action: posix_spawn_file_actions_t? = nil
posix_spawn_file_actions_init(&action);
defer { posix_spawn_file_actions_destroy(&action) }
let m: mode_t = S_IRWXU | S_IRWXG | S_IRWXO
posix_spawn_file_actions_addopen(&action, 1, "/tmp/shell", (O_WRONLY | O_CREAT | O_TRUNC), m)

let args = ["/usr/bin/env", "ps", "-p", "\(getppid())", "-o", "comm="]
let c_args = args.map { $0.withCString(strdup)! }
defer { for arg in c_args { free(arg) } }

var pid = pid_t()
let rv = posix_spawn(&pid, c_args[0], &action, nil, c_args + [nil], environ)
guard rv == 0 else {
  // Should get errno
  exit(1)
}
//print(pid)

var exitCode: Int32 = 0
waitpid(pid, &exitCode, 0)

adapted from the method of determining PS1. read /tmp/shell and see something like -bash, zsh, nu, csh, etc.

After running this:

[sam](~)$ repl git
Initializing REPL with command: git
Use ^D to exit

[sam](~)$ git status
fatal: not a git repository (or any of the parent directories): .git
[sam](~)$ git config --global user.name "Samasaur1"
[sam](~)$ git ^D
Exiting REPL

bash's history does not contain the git lines. This means that !! does not work, nor does history or arrow keys after exiting REPL.

Any commands run in the REPL should be added to the history. I'm not sure how hard this is to do, but if possible it should be done.

REPL should, instead of using my current prompt, read from user config files to duplicate their prompt

My problem is that I apparently shouldn't be using the C signal handlers that I am using, and that I can't find SIGTSTP to trap on anyway

In macOS's Terminal.app running bash, Ctrl-C (^C) leaves what's on the line and produces a new line. REPL should emulate this.

The README should have usage instructions and a GIF/MOV, most likely

When REPL is used on tools that produced colored output (the example I'm thinking of is git), the colors are not seen. This should be remedied.

This is because I haven't linked the standard input in Swift to the standard input of the Process, but dealing with Process is a pain in general, so I'm just going to rely on #10, since I know it will fix the issue

Although #11 mocks the user's PS1 for the REPL prompt, there are a few problems with this. First, if you use a shell other than bash, you're up a creek without a paddle. Second, you may perhaps want a different REPL prompt than your bash prompt.

This config file would probably go in ~/.config/repl/ and should also include the aliases in #12

REPL should support up and down arrow keys to go through terminal history. Right now, all it produces is ^[[A for up arrow and ^[[B for down arrow.

I know the title makes it seem like we're going backwards in time, not forwards, but in my experience something like the following works better:

var pid: pid_t = 0
let args = ["/usr/bin/env"] + effectiveEditor + [dir + "/" + helpme + ".txt"]
let c_args = args.map { $0.withCString(strdup)! }
posix_spawn(&pid, c_args[0], nil, nil, c_args + [nil], environ)
waitpid(pid, nil, 0)

(from helpme-swiftly)

This should also work better with lots of arguments, especially quoted ones, since we're invoking the actual command rather than /bin/bash -c "command and arguments"

I don't know if I actually want to use the GNU readline, but I want support for ^A, ^E, ^W, etc. — so that it feels like a standard shell edit line.

see #18

As mentioned in #7 and #6, REPL should support using !! to refer to the previous command. This specifically relates to #6, as the work being done for that (having a history of commands) means that substituting !! for the previous command should be easy.

While we're waiting for #5, it would be nice to have aliases configurable in REPL. For example, to get color in git right now, instead of saying repl git, I say repl git -c color.ui=always -c color.status=always. For ls, it's ls --color=auto.

It would be nice to have repl check some configuration file and, if the input command matches, substitute it for the longer one. This would be easy, be a simpler way to enable color than faking being a tty/opening a pty, and would be useful beyond enabling color.

The configuration file should be combined with #13¹