dorothy: prompt for repl shell, and install/configure the repl shell

README.md

@@ -127,12 +127,7 @@ bash -ic "$(curl -fsSL https://dorothy.bevry.me/run)" -- echo-verbose a b c
 To run multiple commands in/from a Dorothy-configured REPL, enter the following line by line:
 
 ```bash
-# to invoke a configured bash shell, use:
 bash -ic "$(curl -fsSL https://dorothy.bevry.me/shell)"
-# to invoke a configured fish shell, use:
-bash -ic "$(curl -fsSL https://dorothy.bevry.me/shell?shell=fish)"
-# to invoke a configured nu shell, use:
-bash -ic "$(curl -fsSL https://dorothy.bevry.me/shell?shell=nu)"
 # if your shell doesn't recognize any of the above syntax, run `bash -i` then try again
 
 # now you can whatever and how many commands as you'd like, such as:
@@ -169,9 +164,10 @@ To select your login shell, run `select-shell`.
 If packages are failing to install, [go back to the "Prerequisites" section](https://github.com/bevry/dorothy#prerequisites).
 
 If your shell doesn't recognise any of the Dorothy commands (you get a command not found error, or an undefined/unbound variable error), then it could be that:
-- Your shell is not running as a login shell. [Verify that your Terminal is running the shell as a login shell.](https://github.com/bevry/dorothy/blob/master/docs/dorothy/dorothy-not-loading.md).
-- Dorothy did not configure itself for the shell you use. Re-run the Dorothy installation process, and be sure to configure Dorothy for your shell.
-- Your login shell is not one of the Dorothy supported shells (Bash, Zsh, Fish, Nu). [Create an issue requesting support for your shell.](https://github.com/bevry/dorothy/issues)
+
+-   Your shell is not running as a login shell. [Verify that your Terminal is running the shell as a login shell.](https://github.com/bevry/dorothy/blob/master/docs/dorothy/dorothy-not-loading.md).
+-   Dorothy did not configure itself for the shell you use. Re-run the Dorothy installation process, and be sure to configure Dorothy for your shell.
+-   Your login shell is not one of the Dorothy supported shells (Bash, Zsh, Fish, Nu). [Create an issue requesting support for your shell.](https://github.com/bevry/dorothy/issues)
 
 ## Overview
 

commands/dorothy

@@ -1225,7 +1225,7 @@ function dorothy() (
 	# default to [shell=bash] instead of [sh] as [sh] is [dash] on ubuntu, and [dash] doesn't support the [--...] args
 	function act_shell {
 		# process arguments
-		local item shell='bash' theme=''
+		local item shell='' theme=''
 		while test "$#" -ne 0; do
 			item="$1"
 			shift
@@ -1242,13 +1242,18 @@ function dorothy() (
 		assert_dorothy_configured
 		ensure_minimal_dependencies
 
-		# compatibility
-		if command_missing "$shell"; then
-			echo-error 'Cannot use --shell=' --invert="$shell" ' as that shell is not available on this system.'
-			return 3 # ESRCH 3 No such process
+		# ask
+		if test -z "$shell"; then
+			shell="$(
+				choose-option --required \
+					--question='Which shell to use?' \
+					-- bash fish nu
+			)"
 		fi
 
+		# act, installing the shell if it is missing
 		if test "$shell" = 'bash'; then
+			setup-util-bash --quiet
 			# [bash --rcfile] works but not within a [--rcfile]
 			# [--login] ignores [--rcfile]
 			# this is not a true login shell, as [$0] is not [-bash], as such loading [init.sh] is incompatible
@@ -1260,29 +1265,31 @@ function dorothy() (
 					DOROTHY_LOADED=no
 					DOROTHY_THEME_OVERRIDE='$theme'
 					. '$DOROTHY/init.sh'
-					echo-style 'Your are now using the ' --code='$ACTIVE_POSIX_SHELL' ' shell with Dorothy loaded from ' --code='$DOROTHY' \$'\n' 'Use the ' --code='exit' ' command to return to your parent shell.' \$'\n' 'Use ' --code='ls $DOROTHY/commands' ' to see available commands.'
+					echo-style 'Your are now using the ' --invert='$ACTIVE_POSIX_SHELL' ' shell with Dorothy loaded from ' --code='$DOROTHY' \$'\n' 'Use the ' --code='exit' ' command to return to your parent shell.' \$'\n' 'Use ' --code='ls $DOROTHY/commands' ' to see available commands.'
 				EOF
 			)
 		elif test "$shell" = 'nu'; then
+			setup-util-nu --quiet # this is necessary for nushell, even if installed, as it requires all config files to exist prior
 			"$shell" --interactive --login --no-config-file --execute "$(
 				cat <<-EOF
 					#!/usr/bin/env nu
 					\$env.DOROTHY_THEME_OVERRIDE = '$theme'
 					source '$DOROTHY/init.nu'
-					echo-style 'Your are now using the ' --code=nu ' shell with Dorothy loaded from ' --code='$DOROTHY' "\n" 'Use the ' --code='exit' ' command to return to your parent shell.' "\n" 'Use ' --code='ls $DOROTHY/commands' ' to see available commands.'
+					echo-style 'Your are now using the ' --invert='nu' ' shell with Dorothy loaded from ' --code='$DOROTHY' "\n" 'Use the ' --code='exit' ' command to return to your parent shell.' "\n" 'Use ' --code='ls $DOROTHY/commands' ' to see available commands.'
 				EOF
 			)"
 		elif test "$shell" = 'fish'; then
+			setup-util-fish --quiet
 			"$shell" --interactive --login --no-config --init-command="$(
 				cat <<-EOF
 					#!/usr/bin/env fish
 					set DOROTHY_THEME_OVERRIDE '$theme'
 					source '$DOROTHY/init.fish'
-					echo-style 'Your are now using the ' --code=fish ' shell with Dorothy loaded from ' --code='$DOROTHY' \n 'Use the ' --code='exit' ' command to return to your parent shell.' \n 'Use ' --code='ls $DOROTHY/commands' ' to see available commands.'
+					echo-style 'Your are now using the ' --invert='fish' ' shell with Dorothy loaded from ' --code='$DOROTHY' \n 'Use the ' --code='exit' ' command to return to your parent shell.' \n 'Use ' --code='ls $DOROTHY/commands' ' to see available commands.'
 				EOF
 			)"
 		else
-			echo-error 'Cannot use --shell=' --invert="$shell" ' as that shell does not support REPLs with custom configuration.'
+			echo-error 'Cannot use ' --invert="$shell" ' as that shell does not support REPLs with custom configuration.'
 			return 93 # EPROTONOSUPPORT 93 Protocol not supported
 		fi
 	}