diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -3671,8 +3671,12 @@ def debugtemplate(ui, repo, tmpl, **opts
             raise error.Abort(_('malformed keyword definition: %s') % d)
 
     if ui.verbose:
+        aliases = ui.configitems('templatealias')
         tree = templater.parse(tmpl)
         ui.note(templater.prettyformat(tree), '\n')
+        newtree = templater.expandaliases(tree, aliases)
+        if newtree != tree:
+            ui.note("* expanded:\n", templater.prettyformat(newtree), '\n')
 
     mapfile = None
     if revs is None:
diff --git a/mercurial/templater.py b/mercurial/templater.py
--- a/mercurial/templater.py
+++ b/mercurial/templater.py
@@ -872,6 +872,25 @@ exprmethods = {
 methods = exprmethods.copy()
 methods["integer"] = exprmethods["symbol"]  # '{1}' as variable
 
+class _aliasrules(parser.basealiasrules):
+    """Parsing and expansion rule set of template aliases"""
+    _section = _('template alias')
+    _parse = staticmethod(_parseexpr)
+
+    @staticmethod
+    def _trygetfunc(tree):
+        """Return (name, args) if tree is func(...) or ...|filter; otherwise
+        None"""
+        if tree[0] == 'func' and tree[1][0] == 'symbol':
+            return tree[1][1], getlist(tree[2])
+        if tree[0] == '|' and tree[2][0] == 'symbol':
+            return tree[2][1], [tree[1]]
+
+def expandaliases(tree, aliases):
+    """Return new tree of aliases are expanded"""
+    aliasmap = _aliasrules.buildmap(aliases)
+    return _aliasrules.expand(aliasmap, tree)
+
 # template engine
 
 stringify = templatefilters.stringify
diff --git a/tests/test-command-template.t b/tests/test-command-template.t
--- a/tests/test-command-template.t
+++ b/tests/test-command-template.t
@@ -3654,6 +3654,100 @@ json filter should escape HTML tags so t
   $ hg log -T "{'<foo@example.org>'|json}\n" -R a -l1
   "\u003cfoo@example.org\u003e"
 
+Templater supports aliases of symbol and func() styles:
+
+  $ hg clone -q a aliases
+  $ cd aliases
+  $ cat <<EOF >> .hg/hgrc
+  > [templatealias]
+  > r = rev
+  > rn = "{r}:{node|short}"
+  > status(c, files) = files % "{c} {file}\n"
+  > utcdate(d) = localdate(d, "UTC")
+  > EOF
+
+  $ hg debugtemplate -vr0 '{rn} {utcdate(date)|isodate}\n'
+  (template
+    ('symbol', 'rn')
+    ('string', ' ')
+    (|
+      (func
+        ('symbol', 'utcdate')
+        ('symbol', 'date'))
+      ('symbol', 'isodate'))
+    ('string', '\n'))
+  * expanded:
+  (template
+    (template
+      ('symbol', 'rev')
+      ('string', ':')
+      (|
+        ('symbol', 'node')
+        ('symbol', 'short')))
+    ('string', ' ')
+    (|
+      (func
+        ('symbol', 'localdate')
+        (list
+          ('symbol', 'date')
+          ('string', 'UTC')))
+      ('symbol', 'isodate'))
+    ('string', '\n'))
+  hg: parse error: unknown function 'utcdate'
+  [255]
+
+  $ hg debugtemplate -vr0 '{status("A", file_adds)}'
+  (template
+    (func
+      ('symbol', 'status')
+      (list
+        ('string', 'A')
+        ('symbol', 'file_adds'))))
+  * expanded:
+  (template
+    (%
+      ('symbol', 'file_adds')
+      (template
+        ('string', 'A')
+        ('string', ' ')
+        ('symbol', 'file')
+        ('string', '\n'))))
+  hg: parse error: unknown function 'status'
+  [255]
+
+A unary function alias can be called as a filter:
+
+  $ hg debugtemplate -vr0 '{date|utcdate|isodate}\n'
+  (template
+    (|
+      (|
+        ('symbol', 'date')
+        ('symbol', 'utcdate'))
+      ('symbol', 'isodate'))
+    ('string', '\n'))
+  * expanded:
+  (template
+    (|
+      (func
+        ('symbol', 'localdate')
+        (list
+          ('symbol', 'date')
+          ('string', 'UTC')))
+      ('symbol', 'isodate'))
+    ('string', '\n'))
+  hg: parse error: unknown function 'utcdate'
+  [255]
+
+Unparsable alias:
+
+  $ hg debugtemplate --config templatealias.bad='x(' -v '{bad}'
+  (template
+    ('symbol', 'bad'))
+  abort: failed to parse the definition of template alias "bad": at 2: not a prefix: end
+  [255]
+
+  $ cd ..
+
 Set up repository for non-ascii encoding tests:
 
   $ hg init nonascii