[PATCH] ui: add function 'promptselection'

[Ingo Proetel]

# HG changeset patch
# User Ingo Proetel <proetel at aicas.de>
# Date 1313046309 -7200
# Node ID 3ab40477ce60e1757ceeaa49e2c9d2790fbb47e0
# Parent  f4522df38c658a1768ffe08c864575e119b327ce
ui: add function 'promptselection'

diff -r f4522df38c65 -r 3ab40477ce60 mercurial/ui.py
--- a/mercurial/ui.py	Tue Aug 02 15:21:10 2011 -0400
+++ b/mercurial/ui.py	Thu Aug 11 09:05:09 2011 +0200
@@ -584,6 +584,60 @@
                 return resps.index(r.lower())
             self.write(_("unrecognized response\n"))
 
+    def promptselection(self, msg, choices, default=None):
+        '''Prompt user with msg, read response, and ensure it matches
+        one of the provided choices. choices is a sequence of tuples
+        with the format: (('command', _('help for &command')),...). command
+        is a non-localized string that will be the return value. Help texts are
+        localized and mark the expected user selection char with a '&'. A help
+        command for will be provided for input '?'. Responses are case
+        insensitive. If ui is not interactive, the default is returned.
+        If no default is given the first entry in choices is used.
+        Example:
+        choices = (('abort', _('&Abort command')),
+                   ('new', _('Create &new request')),
+                   ('reopen', _('&Reopen request')) )
+        request = ui.promptselection('now what?', choices, 'new')
+        if request == 'abort':
+          raise util.Abort('User aborted')
+        elif request == 'new':
+          ui.status('creating new')
+        else:
+          ui.status('reopen existing')
+        will ask:
+        $now what? [aNr?] ?
+        a Abort command
+        n Create new request
+        r Reopen request
+        $now what? [aNr?] n
+        creating new
+        '''
+        responses = ''
+        for choice in choices:
+            command = choice[0]
+            helptext = choice[1]
+            commandchar = helptext[helptext.index('&') + 1].lower()
+
+            if not default or default == command:
+                default = command
+                defaultchar = commandchar
+                commandchar = commandchar.upper()
+            responses += commandchar
+
+        while True:
+            r = self.prompt('%s [%s?]' % (msg, responses), defaultchar)
+            index = responses.lower().find(r.lower())
+            if index > -1:
+                return choices[index][0]
+            elif r == '?':
+                for choice in choices:
+                    commandchar = choice[1][choice[1].index('&') + 1].lower()
+                    helptext = choice[1].replace('\&', '')
+                    self.write(' %s %s\n' % (commandchar, helptext))
+                self.write('\n')
+            else :
+                self.write(_("unrecognized response\n"))
+
     def getpass(self, prompt=None, default=None):
         if not self.interactive():
             return default