[Agnoster theme] Add the prompt view customization ability

themes/agnoster.zsh-theme

@@ -29,6 +29,20 @@
 # jobs are running in this shell will all be displayed automatically when
 # appropriate.
 
+### Segments of the prompt default order declaration
+
+typeset -aHg AGNOSTER_PROMPT=(
+    prompt_status
+    prompt_virtualenv
+    prompt_aws
+    prompt_context
+    prompt_dir
+    prompt_git
+    prompt_bzr
+    prompt_hg
+    prompt_end
+)
+
 ### Segment drawing
 # A few utility functions to make it easy and re-usable to draw segmented prompts
 
@@ -239,15 +253,9 @@ prompt_aws() {
 ## Main prompt
 build_prompt() {
   RETVAL=$?
-  prompt_status
-  prompt_virtualenv
-  prompt_aws
-  prompt_context
-  prompt_dir
-  prompt_git
-  prompt_bzr
-  prompt_hg
-  prompt_end
+  for prompt_segment in "${AGNOSTER_PROMPT[@]}"; do
+    [[ -n $prompt_segment ]] && $prompt_segment
+  done
 }
 
 PROMPT='%{%f%b%k%}$(build_prompt) '