plugins/xterm: Refactor

* plugins/xterm: Add header line as an OMB plugin
* plugins/xterm: Add link to the upstream version
* plugins/xterm: Add the list of the configuration variables
* plugins/xterm: Do not rely on the function "cite"
* plugins/xterm: Add dependency to bash-preexec
* plugins/xterm: Use "function func" to avoid aliasing
* plugins/xterm: Namespacing function names
* plugins/xterm: Namespacing configuration variables
* plugins/xterm (_omb_plugin_xterm_set_title): Avoid expanding escapes in directory names, etc.
* plugins/xterm: Always enable precmd/preexec because the plugin should be enabled by the users' decision
* plugins/xterm: Do no unneccessarily add braces around ${var}
* plugins/xterm: Do no uneccessarily quote words

plugins/xterm/xterm.plugin.bash

@@ -1,45 +1,52 @@
-# shellcheck shell=bash
-cite about-plugin
-about-plugin 'automatically set your xterm title with host and location info'
-
-_short-dirname() {
-	local dir_name="${PWD/~/\~}"
-	if [[ "${SHORT_TERM_LINE:-}" == true && "${#dir_name}" -gt 8 ]]; then
-		echo "${dir_name##*/}"
-	else
-		echo "${dir_name}"
-	fi
+#! bash oh-my-bash.module
+# Description: automatically set your xterm title with host and location info'
+# Source: https://github.com/Bash-it/bash-it/blob/bf2034d13d/plugins/available/xterm.plugin.bash
+#
+# @var[opt] PROMPT_CHAR ... This variable is shared with powerline
+# @var[opt] OMB_PLUGIN_XTERM_SHORT_TERM_LINE
+# @var[opt] OMB_PLUGIN_XTERM_SHORT_USER
+# @var[opt] OMB_PLUGIN_XTERM_SHORT_HOSTNAME
+#
+
+_omb_module_require plugin:bash-preexec
+
+function _omb_plugin_xterm_short_dirname {
+  local dir_name=${PWD/~/\~}
+  if [[ ${OMB_PLUGIN_XTERM_SHORT_TERM_LINE-} == true ]] && ((${#dir_name} > 8)); then
+    dir_name=${dir_name##*/}
+  fi
+  echo "$dir_name"
 }
 
-_short-command() {
-	local input_command="$*"
-	if [[ "${SHORT_TERM_LINE:-}" == true && "${#input_command}" -gt 8 ]]; then
-		echo "${input_command%% *}"
-	else
-		echo "${input_command}"
-	fi
+function _omb_plugin_xterm_short_command {
+  local input_command="$*"
+  if [[ ${OMB_PLUGIN_XTERM_SHORT_TERM_LINE-} == true ]] ((${#input_command} > 8)); then
+    input_command=${input_command%% *}
+  fi
+  echo "$input_command"
 }
 
-set_xterm_title() {
-	local title="${1:-}"
-	echo -ne "\033]0;${title}\007"
+function _omb_plugin_xterm_set_title {
+  local title=${1-}
+  printf '\e]0;%s\e\\' "$title"
 }
 
-precmd_xterm_title() {
-	set_xterm_title "${SHORT_USER:-${USER}}@${SHORT_HOSTNAME:-${HOSTNAME}} $(_short-dirname) ${PROMPT_CHAR:-\$}"
+function _omb_plugin_xterm_precmd_title {
+  local user=${OMB_PLUGIN_XTERM_SHORT_USER:-$USER}
+  local host=${OMB_PLUGIN_XTERM_SHORT_HOSTNAME:-$HOSTNAME}
+  _omb_plugin_xterm_set_title "$user@$host $(_omb_plugin_xterm_short_dirname) ${PROMPT_CHAR:-\$}"
 }
 
-preexec_xterm_title() {
-	local command_line="${BASH_COMMAND:-${1:-}}"
-	local directory_name short_command
-	directory_name="$(_short-dirname)"
-	short_command="$(_short-command "${command_line}")"
-	set_xterm_title "${short_command} {${directory_name}} (${SHORT_USER:-${USER}}@${SHORT_HOSTNAME:-${HOSTNAME}})"
+function _omb_plugin_xterm_preexec_title {
+  local command_line=${BASH_COMMAND:-${1:-}}
+  local directory_name=$(_omb_plugin_xterm_short_dirname)
+  local short_command=$(_omb_plugin_xterm_short_command "$command_line")
+  local user=${OMB_PLUGIN_XTERM_SHORT_USER:-$USER}
+  local host=${OMB_PLUGIN_XTERM_SHORT_HOSTNAME:-$HOSTNAME}
+  _omb_plugin_xterm_set_title "$short_command {$directory_name} ($user@$host)"
 }
 
-case "${TERM:-dumb}" in
-	xterm* | rxvt*)
-		precmd_functions+=(precmd_xterm_title)
-		preexec_functions+=(preexec_xterm_title)
-		;;
-esac
+function set_xterm_title { _omb_plugin_xterm_set_title "$@"; }
+
+precmd_functions+=(_omb_plugin_xterm_precmd_title)
+preexec_functions+=(_omb_plugin_xterm_preexec_title)