show: config option to register aliases for views

As part of using `hg show` in my daily workflow, I've found it slightly
annoying to have to type full view names, complete with a space. I've
locally registered an alias for "swork = show work."

I think others will have this same complaint and could benefit from
some automation to streamline the creation of aliases. So, this
commit introduces a config option that allows `hg show` views to be
automatically aliased using a given prefix. e.g. a value of "s"
will automatically register "swork" and "sbookmarks." Multiple
values can be given for ultimate flexibility. This arguably isn't
needed now. But since we don't register aliases if there will be
a collision and we're bound to have a collision, it makes sense to
allow multiple prefixes so specific views can avoid collisions by
using different prefixes.

hgext/show.py

@@ -10,6 +10,19 b''
 This extension provides the :hg:`show` command, which provides a central
 command for displaying commonly-accessed repository data and views of that
 data.
+
+The following config options can influence operation.
+
+``commands``
+------------
+
+``show.aliasprefix``
+   List of strings that will register aliases for views. e.g. ``s`` will
+   effectively set config options ``alias.s<view> = show <view>`` for all
+   views. i.e. `hg swork` would execute `hg show work`.
+
+   Aliases that would conflict with existing registrations will not be
+   performed.
 """
 
 from __future__ import absolute_import
@@ -18,6 +31,7 b' from mercurial.i18n import _'
 from mercurial.node import nullrev
 from mercurial import (
     cmdutil,
+    commands,
     error,
     formatter,
     graphmod,
@@ -218,6 +232,25 b' def showwork(ui, repo, displayer):'
     ui.setconfig('experimental', 'graphshorten', True)
     cmdutil.displaygraph(ui, repo, revdag, displayer, graphmod.asciiedges)
 
+def extsetup(ui):
+    # Alias `hg <prefix><view>` to `hg show <view>`.
+    for prefix in ui.configlist('commands', 'show.aliasprefix'):
+        for view in showview._table:
+            name = '%s%s' % (prefix, view)
+
+            choice, allcommands = cmdutil.findpossible(name, commands.table,
+                                                       strict=True)
+
+            # This alias is already a command name. Don't set it.
+            if name in choice:
+                continue
+
+            # Same for aliases.
+            if ui.config('alias', name):
+                continue
+
+            ui.setconfig('alias', name, 'show %s' % view, source='show')
+
 # Adjust the docstring of the show command so it shows all registered views.
 # This is a bit hacky because it runs at the end of module load. When moved
 # into core or when another extension wants to provide a view, we'll need

tests/test-show.t

@@ -127,4 +127,42 b' JSON works with no bookmarks'
   [
   ]
 
+commands.show.aliasprefix aliases values to `show <view>`
+
+  $ hg --config commands.show.aliasprefix=s sbookmarks
+  (no bookmarks set)
+
+  $ hg --config commands.show.aliasprefix=sh shwork
+  @  7b570 commit for book2
+  o  b757f commit for book1
+  o  ba592 initial
+
+  $ hg --config commands.show.aliasprefix='s sh' swork
+  @  7b570 commit for book2
+  o  b757f commit for book1
+  o  ba592 initial
+
+  $ hg --config commands.show.aliasprefix='s sh' shwork
+  @  7b570 commit for book2
+  o  b757f commit for book1
+  o  ba592 initial
+
+The aliases don't appear in `hg config`
+
+  $ hg --config commands.show.aliasprefix=s config alias
+  [1]
+
+Doesn't overwrite existing alias
+
+  $ hg --config alias.swork='log -r .' --config commands.show.aliasprefix=s swork
+  changeset:   2:7b5709ab64cb
+  tag:         tip
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     commit for book2
+  
+
+  $ hg --config alias.swork='log -r .' --config commands.show.aliasprefix=s config alias
+  alias.swork=log -r .
+
   $ cd ..