[PATCH 2 of 4] templater: support using templates with non-standard names from map file

[Alexander Plavin]

# HG changeset patch
# User Alexander Plavin <alexander at plav.in>
# Date 1374620882 -14400
#      Wed Jul 24 03:08:02 2013 +0400
# Node ID 9f6c511249aca1e16fd1a50764cc014bcd8b9d85
# Parent  46f03aab5c7e287ac3c28d85de640e6b6abeda3b
templater: support using templates with non-standard names from map file

This allows adding arbitrarily-named entries to a template map file, and then
referencing them, giving the ability to deduplicate and simplify templates code.

diff -r 46f03aab5c7e -r 9f6c511249ac mercurial/templater.py
--- a/mercurial/templater.py	Sat Aug 03 00:34:56 2013 +0400
+++ b/mercurial/templater.py	Wed Jul 24 03:08:02 2013 +0400
@@ -139,7 +139,12 @@
 def runsymbol(context, mapping, key):
     v = mapping.get(key)
     if v is None:
-        v = context._defaults.get(key, '')
+        v = context._defaults.get(key)
+    if v is None:
+        try:
+            v = context.process(key, mapping)
+        except util.Abort:
+            v = ''
     if util.safehasattr(v, '__call__'):
         return v(**mapping)
     if isinstance(v, types.GeneratorType):
diff -r 46f03aab5c7e -r 9f6c511249ac tests/test-command-template.t
--- a/tests/test-command-template.t	Sat Aug 03 00:34:56 2013 +0400
+++ b/tests/test-command-template.t	Wed Jul 24 03:08:02 2013 +0400
@@ -500,6 +500,23 @@
   1
   0
 
+Defining non-standard name works:
+
+  $ cat <<EOF > t
+  > changeset = '{c}'
+  > c = q
+  > EOF
+  $ hg log --style ./t
+  8
+  7
+  6
+  5
+  4
+  3
+  2
+  1
+  0
+
 ui.style works:
 
   $ echo '[ui]' > .hg/hgrc