Merge pull request #49 from gbrindisi/prompt

Added basic yes/no prompt module

AUTHORS

@@ -19,4 +19,5 @@ Patches and Suggestions
 - takluyver
 - kracekumar 
 - Alejandro Gómez <alejandrogomez>
-- Jason Piper <jpiper>
+- Jason Piper <jpiper>
+- Gianluca Brindisi <gbrindisi>

clint/textui/prompt.py

@@ -0,0 +1,49 @@
+# -*- coding: utf8 -*-
+
+"""
+clint.textui.prompt
+~~~~~~~~~~~~~~~~~~~
+
+Module for simple interactive prompts handling
+
+"""
+
+from __future__ import absolute_import
+
+from re import match, I
+
+def yn(prompt, default='y', batch=False):
+    # A sanity check against default value
+    # If not y/n then y is assumed 
+    if default not in ['y', 'n']:
+        default = 'y'
+    
+    # Let's build the prompt
+    choicebox = '[Y/n]' if default == 'y' else '[y/N]' 
+    prompt = prompt + ' ' + choicebox + ' ' 
+
+    # If input is not a yes/no variant or empty
+    # keep asking
+    while True:
+        # If batch option is True then auto reply 
+        # with default input
+        if not batch:
+            input = raw_input(prompt).strip()
+        else:
+            print prompt
+            input = ''
+
+        # If input is empty default choice is assumed
+        # so we return True
+        if input == '':
+            return True
+
+        # Given 'yes' as input if default choice is y
+        # then return True, False otherwise 
+        if match('y(?:es)?', input, I):
+            return True if default == 'y' else False
+
+        # Given 'no' as input if default choice is n
+        # then return True, False otherwise
+        elif match('n(?:o)?', input, I):
+            return True if default == 'n' else False