[environment] add customizable term title

Adds customizable terminal/window title. Set `${ztermtitle}` in `.zimrc`
to use this functionality.

Check the notes added in templates/zimrc for additional usage info.

Closes #52

modules/environment/README.md

@@ -5,6 +5,8 @@ Sets generic Zsh built-in environment options.
 
 Also enables smart URL-pasting. This prevents the user from having to manually escape URLs.
 
+Uses `.zimrc` defined `${ztermtitle}` variable to set the terminal title, if defined.
+
 ZSH Options
 -----------
 

modules/environment/init.zsh

@@ -46,3 +46,14 @@ if [[ -z ${PAGER} ]]; then
     export PAGER=more
   fi
 fi
+
+# sets the window title and updates upon directory change
+# more work probably needs to be done here to support multiplexers
+if (($+ztermtitle)); then
+  case ${TERM} in
+    xterm*)
+      precmd() { print -Pn "\e]0;${ztermtitle}\a" }
+      precmd  # we execute it once to initialize the window title
+      ;;
+  esac
+fi

templates/zimrc

@@ -42,6 +42,17 @@ zprompt_theme='steeef'
 # See: http://zsh.sourceforge.net/Doc/Release/Options.html#Input_002fOutput
 #setopt CORRECT
 
+#
+# Environment
+#
+
+# Set the string below to the desired terminal title format string.
+# The terminal title is redrawn upon directory change, however, variables like 
+# ${PWD} are only evaluated once. Use prompt expansion strings for dynamic data:
+#   http://zsh.sourceforge.net/Doc/Release/Prompt-Expansion.html#Simple-Prompt-Escapes
+# The example below uses the following format: 'username@host:/current/directory'
+ztermtitle='%n@%m:%~'
+
 #
 # Input
 #