templater: make _hybrid not callable to avoid conflicting semantics

In templater, a callable symbol exists for lazy evaluation, which should have
f(**mapping) signature. On the other hand, _hybrid.__call__(), which was
introduced by 0b241d7a8c62, generates mapping for each element.

This patch renames _hybrid.__call__() to _hybrid.itermaps() so that a _hybrid
object can be a value of a mapping dict.

  {namespaces % "{namespace}: {names % "{name }"}\n"}
                               ~~~~~
                               a _hybrid object

mercurial/templatekw.py

@@ -34,7 +34,7 b' class _hybrid(object):'
             self.joinfmt = lambda x: x.values()[0]
     def __iter__(self):
         return self.gen
-    def __call__(self):
+    def itermaps(self):
         makemap = self._makemap
         for x in self.values:
             yield makemap(x)

mercurial/templater.py

@@ -281,8 +281,8 b' def buildmap(exp, context):'
 def runmap(context, mapping, data):
     func, data, ctmpl = data
     d = func(context, mapping, data)
-    if callable(d):
-        d = d()
+    if util.safehasattr(d, 'itermaps'):
+        d = d.itermaps()
 
     lm = mapping.copy()
 
@@ -483,9 +483,9 b' def join(context, mapping, args):'
         raise error.ParseError(_("join expects one or two arguments"))
 
     joinset = args[0][0](context, mapping, args[0][1])
-    if callable(joinset):
+    if util.safehasattr(joinset, 'itermaps'):
         jf = joinset.joinfmt
-        joinset = [jf(x) for x in joinset()]
+        joinset = [jf(x) for x in joinset.itermaps()]
 
     joiner = " "
     if len(args) > 1: