parser: extend buildargsdict() to support arbitrary number of **kwargs

Prepares for adding dict(key1=value1, ...) template function. More tests
will be added later.

mercurial/parser.py

@@ -1,584 +1,604 b''
 # parser.py - simple top-down operator precedence parser for mercurial
 #
 # Copyright 2010 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 # see http://effbot.org/zone/simple-top-down-parsing.htm and
 # http://eli.thegreenplace.net/2010/01/02/top-down-operator-precedence-parsing/
 # for background
 
 # takes a tokenizer and elements
 # tokenizer is an iterator that returns (type, value, pos) tuples
 # elements is a mapping of types to binding strength, primary, prefix, infix
 # and suffix actions
 # an action is a tree node name, a tree label, and an optional match
 # __call__(program) parses program into a labeled tree
 
 from __future__ import absolute_import
 
 from .i18n import _
 from . import (
     error,
     util,
 )
 
 class parser(object):
     def __init__(self, elements, methods=None):
         self._elements = elements
         self._methods = methods
         self.current = None
     def _advance(self):
         'advance the tokenizer'
         t = self.current
         self.current = next(self._iter, None)
         return t
     def _hasnewterm(self):
         'True if next token may start new term'
         return any(self._elements[self.current[0]][1:3])
     def _match(self, m):
         'make sure the tokenizer matches an end condition'
         if self.current[0] != m:
             raise error.ParseError(_("unexpected token: %s") % self.current[0],
                                    self.current[2])
         self._advance()
     def _parseoperand(self, bind, m=None):
         'gather right-hand-side operand until an end condition or binding met'
         if m and self.current[0] == m:
             expr = None
         else:
             expr = self._parse(bind)
         if m:
             self._match(m)
         return expr
     def _parse(self, bind=0):
         token, value, pos = self._advance()
         # handle prefix rules on current token, take as primary if unambiguous
         primary, prefix = self._elements[token][1:3]
         if primary and not (prefix and self._hasnewterm()):
             expr = (primary, value)
         elif prefix:
             expr = (prefix[0], self._parseoperand(*prefix[1:]))
         else:
             raise error.ParseError(_("not a prefix: %s") % token, pos)
         # gather tokens until we meet a lower binding strength
         while bind < self._elements[self.current[0]][0]:
             token, value, pos = self._advance()
             # handle infix rules, take as suffix if unambiguous
             infix, suffix = self._elements[token][3:]
             if suffix and not (infix and self._hasnewterm()):
                 expr = (suffix, expr)
             elif infix:
                 expr = (infix[0], expr, self._parseoperand(*infix[1:]))
             else:
                 raise error.ParseError(_("not an infix: %s") % token, pos)
         return expr
     def parse(self, tokeniter):
         'generate a parse tree from tokens'
         self._iter = tokeniter
         self._advance()
         res = self._parse()
         token, value, pos = self.current
         return res, pos
     def eval(self, tree):
         'recursively evaluate a parse tree using node methods'
         if not isinstance(tree, tuple):
             return tree
         return self._methods[tree[0]](*[self.eval(t) for t in tree[1:]])
     def __call__(self, tokeniter):
         'parse tokens into a parse tree and evaluate if methods given'
         t = self.parse(tokeniter)
         if self._methods:
             return self.eval(t)
         return t
 
 def splitargspec(spec):
-    """Parse spec of function arguments into (poskeys, varkey, keys)
+    """Parse spec of function arguments into (poskeys, varkey, keys, optkey)
 
     >>> splitargspec('')
-    ([], None, [])
+    ([], None, [], None)
     >>> splitargspec('foo bar')
-    ([], None, ['foo', 'bar'])
-    >>> splitargspec('foo *bar baz')
-    (['foo'], 'bar', ['baz'])
+    ([], None, ['foo', 'bar'], None)
+    >>> splitargspec('foo *bar baz **qux')
+    (['foo'], 'bar', ['baz'], 'qux')
     >>> splitargspec('*foo')
-    ([], 'foo', [])
+    ([], 'foo', [], None)
+    >>> splitargspec('**foo')
+    ([], None, [], 'foo')
     """
-    pre, sep, post = spec.partition('*')
+    optkey = None
+    pre, sep, post = spec.partition('**')
+    if sep:
+        posts = post.split()
+        if not posts:
+            raise error.ProgrammingError('no **optkey name provided')
+        if len(posts) > 1:
+            raise error.ProgrammingError('excessive **optkey names provided')
+        optkey = posts[0]
+
+    pre, sep, post = pre.partition('*')
     pres = pre.split()
     posts = post.split()
     if sep:
         if not posts:
             raise error.ProgrammingError('no *varkey name provided')
-        return pres, posts[0], posts[1:]
-    return [], None, pres
+        return pres, posts[0], posts[1:], optkey
+    return [], None, pres, optkey
 
 def buildargsdict(trees, funcname, argspec, keyvaluenode, keynode):
     """Build dict from list containing positional and keyword arguments
 
-    Arguments are specified by a tuple of ``(poskeys, varkey, keys)`` where
+    Arguments are specified by a tuple of ``(poskeys, varkey, keys, optkey)``
+    where
 
     - ``poskeys``: list of names of positional arguments
     - ``varkey``: optional argument name that takes up remainder
     - ``keys``: list of names that can be either positional or keyword arguments
+    - ``optkey``: optional argument name that takes up excess keyword arguments
 
     If ``varkey`` specified, all ``keys`` must be given as keyword arguments.
 
     Invalid keywords, too few positional arguments, or too many positional
     arguments are rejected, but missing keyword arguments are just omitted.
     """
-    poskeys, varkey, keys = argspec
+    poskeys, varkey, keys, optkey = argspec
     kwstart = next((i for i, x in enumerate(trees) if x[0] == keyvaluenode),
                    len(trees))
     if kwstart < len(poskeys):
         raise error.ParseError(_("%(func)s takes at least %(nargs)d positional "
                                  "arguments")
                                % {'func': funcname, 'nargs': len(poskeys)})
     if not varkey and kwstart > len(poskeys) + len(keys):
         raise error.ParseError(_("%(func)s takes at most %(nargs)d positional "
                                  "arguments")
                                % {'func': funcname,
                                   'nargs': len(poskeys) + len(keys)})
     args = {}
     # consume positional arguments
     for k, x in zip(poskeys, trees[:kwstart]):
         args[k] = x
     if varkey:
         args[varkey] = trees[len(args):kwstart]
     else:
         for k, x in zip(keys, trees[len(args):kwstart]):
             args[k] = x
     # remainder should be keyword arguments
+    if optkey:
+        args[optkey] = {}
     for x in trees[kwstart:]:
         if x[0] != keyvaluenode or x[1][0] != keynode:
             raise error.ParseError(_("%(func)s got an invalid argument")
                                    % {'func': funcname})
         k = x[1][1]
-        if k not in keys:
+        if k in keys:
+            d = args
+        elif not optkey:
             raise error.ParseError(_("%(func)s got an unexpected keyword "
                                      "argument '%(key)s'")
                                    % {'func': funcname, 'key': k})
-        if k in args:
+        else:
+            d = args[optkey]
+        if k in d:
             raise error.ParseError(_("%(func)s got multiple values for keyword "
                                      "argument '%(key)s'")
                                    % {'func': funcname, 'key': k})
-        args[k] = x[2]
+        d[k] = x[2]
     return args
 
 def unescapestr(s):
     try:
         return util.unescapestr(s)
     except ValueError as e:
         # mangle Python's exception into our format
         raise error.ParseError(str(e).lower())
 
 def _prettyformat(tree, leafnodes, level, lines):
     if not isinstance(tree, tuple) or tree[0] in leafnodes:
         lines.append((level, str(tree)))
     else:
         lines.append((level, '(%s' % tree[0]))
         for s in tree[1:]:
             _prettyformat(s, leafnodes, level + 1, lines)
         lines[-1:] = [(lines[-1][0], lines[-1][1] + ')')]
 
 def prettyformat(tree, leafnodes):
     lines = []
     _prettyformat(tree, leafnodes, 0, lines)
     output = '\n'.join(('  ' * l + s) for l, s in lines)
     return output
 
 def simplifyinfixops(tree, targetnodes):
     """Flatten chained infix operations to reduce usage of Python stack
 
     >>> def f(tree):
     ...     print prettyformat(simplifyinfixops(tree, ('or',)), ('symbol',))
     >>> f(('or',
     ...     ('or',
     ...       ('symbol', '1'),
     ...       ('symbol', '2')),
     ...     ('symbol', '3')))
     (or
       ('symbol', '1')
       ('symbol', '2')
       ('symbol', '3'))
     >>> f(('func',
     ...     ('symbol', 'p1'),
     ...     ('or',
     ...       ('or',
     ...         ('func',
     ...           ('symbol', 'sort'),
     ...           ('list',
     ...             ('or',
     ...               ('or',
     ...                 ('symbol', '1'),
     ...                 ('symbol', '2')),
     ...               ('symbol', '3')),
     ...             ('negate',
     ...               ('symbol', 'rev')))),
     ...         ('and',
     ...           ('symbol', '4'),
     ...           ('group',
     ...             ('or',
     ...               ('or',
     ...                 ('symbol', '5'),
     ...                 ('symbol', '6')),
     ...               ('symbol', '7'))))),
     ...       ('symbol', '8'))))
     (func
       ('symbol', 'p1')
       (or
         (func
           ('symbol', 'sort')
           (list
             (or
               ('symbol', '1')
               ('symbol', '2')
               ('symbol', '3'))
             (negate
               ('symbol', 'rev'))))
         (and
           ('symbol', '4')
           (group
             (or
               ('symbol', '5')
               ('symbol', '6')
               ('symbol', '7'))))
         ('symbol', '8')))
     """
     if not isinstance(tree, tuple):
         return tree
     op = tree[0]
     if op not in targetnodes:
         return (op,) + tuple(simplifyinfixops(x, targetnodes) for x in tree[1:])
 
     # walk down left nodes taking each right node. no recursion to left nodes
     # because infix operators are left-associative, i.e. left tree is deep.
     # e.g. '1 + 2 + 3' -> (+ (+ 1 2) 3) -> (+ 1 2 3)
     simplified = []
     x = tree
     while x[0] == op:
         l, r = x[1:]
         simplified.append(simplifyinfixops(r, targetnodes))
         x = l
     simplified.append(simplifyinfixops(x, targetnodes))
     simplified.append(op)
     return tuple(reversed(simplified))
 
 def parseerrordetail(inst):
     """Compose error message from specified ParseError object
     """
     if len(inst.args) > 1:
         return _('at %d: %s') % (inst.args[1], inst.args[0])
     else:
         return inst.args[0]
 
 class alias(object):
     """Parsed result of alias"""
 
     def __init__(self, name, args, err, replacement):
         self.name = name
         self.args = args
         self.error = err
         self.replacement = replacement
         # whether own `error` information is already shown or not.
         # this avoids showing same warning multiple times at each
         # `expandaliases`.
         self.warned = False
 
 class basealiasrules(object):
     """Parsing and expansion rule set of aliases
 
     This is a helper for fileset/revset/template aliases. A concrete rule set
     should be made by sub-classing this and implementing class/static methods.
 
     It supports alias expansion of symbol and function-call styles::
 
         # decl = defn
         h = heads(default)
         b($1) = ancestors($1) - ancestors(default)
     """
     # typically a config section, which will be included in error messages
     _section = None
     # tag of symbol node
     _symbolnode = 'symbol'
 
     def __new__(cls):
         raise TypeError("'%s' is not instantiatable" % cls.__name__)
 
     @staticmethod
     def _parse(spec):
         """Parse an alias name, arguments and definition"""
         raise NotImplementedError
 
     @staticmethod
     def _trygetfunc(tree):
         """Return (name, args) if tree is a function; otherwise None"""
         raise NotImplementedError
 
     @classmethod
     def _builddecl(cls, decl):
         """Parse an alias declaration into ``(name, args, errorstr)``
 
         This function analyzes the parsed tree. The parsing rule is provided
         by ``_parse()``.
 
         - ``name``: of declared alias (may be ``decl`` itself at error)
         - ``args``: list of argument names (or None for symbol declaration)
         - ``errorstr``: detail about detected error (or None)
 
         >>> sym = lambda x: ('symbol', x)
         >>> symlist = lambda *xs: ('list',) + tuple(sym(x) for x in xs)
         >>> func = lambda n, a: ('func', sym(n), a)
         >>> parsemap = {
         ...     'foo': sym('foo'),
         ...     '$foo': sym('$foo'),
         ...     'foo::bar': ('dagrange', sym('foo'), sym('bar')),
         ...     'foo()': func('foo', None),
         ...     '$foo()': func('$foo', None),
         ...     'foo($1, $2)': func('foo', symlist('$1', '$2')),
         ...     'foo(bar_bar, baz.baz)':
         ...         func('foo', symlist('bar_bar', 'baz.baz')),
         ...     'foo(bar($1, $2))':
         ...         func('foo', func('bar', symlist('$1', '$2'))),
         ...     'foo($1, $2, nested($1, $2))':
         ...         func('foo', (symlist('$1', '$2') +
         ...                      (func('nested', symlist('$1', '$2')),))),
         ...     'foo("bar")': func('foo', ('string', 'bar')),
         ...     'foo($1, $2': error.ParseError('unexpected token: end', 10),
         ...     'foo("bar': error.ParseError('unterminated string', 5),
         ...     'foo($1, $2, $1)': func('foo', symlist('$1', '$2', '$1')),
         ... }
         >>> def parse(expr):
         ...     x = parsemap[expr]
         ...     if isinstance(x, Exception):
         ...         raise x
         ...     return x
         >>> def trygetfunc(tree):
         ...     if not tree or tree[0] != 'func' or tree[1][0] != 'symbol':
         ...         return None
         ...     if not tree[2]:
         ...         return tree[1][1], []
         ...     if tree[2][0] == 'list':
         ...         return tree[1][1], list(tree[2][1:])
         ...     return tree[1][1], [tree[2]]
         >>> class aliasrules(basealiasrules):
         ...     _parse = staticmethod(parse)
         ...     _trygetfunc = staticmethod(trygetfunc)
         >>> builddecl = aliasrules._builddecl
         >>> builddecl('foo')
         ('foo', None, None)
         >>> builddecl('$foo')
         ('$foo', None, "invalid symbol '$foo'")
         >>> builddecl('foo::bar')
         ('foo::bar', None, 'invalid format')
         >>> builddecl('foo()')
         ('foo', [], None)
         >>> builddecl('$foo()')
         ('$foo()', None, "invalid function '$foo'")
         >>> builddecl('foo($1, $2)')
         ('foo', ['$1', '$2'], None)
         >>> builddecl('foo(bar_bar, baz.baz)')
         ('foo', ['bar_bar', 'baz.baz'], None)
         >>> builddecl('foo($1, $2, nested($1, $2))')
         ('foo($1, $2, nested($1, $2))', None, 'invalid argument list')
         >>> builddecl('foo(bar($1, $2))')
         ('foo(bar($1, $2))', None, 'invalid argument list')
         >>> builddecl('foo("bar")')
         ('foo("bar")', None, 'invalid argument list')
         >>> builddecl('foo($1, $2')
         ('foo($1, $2', None, 'at 10: unexpected token: end')
         >>> builddecl('foo("bar')
         ('foo("bar', None, 'at 5: unterminated string')
         >>> builddecl('foo($1, $2, $1)')
         ('foo', None, 'argument names collide with each other')
         """
         try:
             tree = cls._parse(decl)
         except error.ParseError as inst:
             return (decl, None, parseerrordetail(inst))
 
         if tree[0] == cls._symbolnode:
             # "name = ...." style
             name = tree[1]
             if name.startswith('$'):
                 return (decl, None, _("invalid symbol '%s'") % name)
             return (name, None, None)
 
         func = cls._trygetfunc(tree)
         if func:
             # "name(arg, ....) = ...." style
             name, args = func
             if name.startswith('$'):
                 return (decl, None, _("invalid function '%s'") % name)
             if any(t[0] != cls._symbolnode for t in args):
                 return (decl, None, _("invalid argument list"))
             if len(args) != len(set(args)):
                 return (name, None, _("argument names collide with each other"))
             return (name, [t[1] for t in args], None)
 
         return (decl, None, _("invalid format"))
 
     @classmethod
     def _relabelargs(cls, tree, args):
         """Mark alias arguments as ``_aliasarg``"""
         if not isinstance(tree, tuple):
             return tree
         op = tree[0]
         if op != cls._symbolnode:
             return (op,) + tuple(cls._relabelargs(x, args) for x in tree[1:])
 
         assert len(tree) == 2
         sym = tree[1]
         if sym in args:
             op = '_aliasarg'
         elif sym.startswith('$'):
             raise error.ParseError(_("invalid symbol '%s'") % sym)
         return (op, sym)
 
     @classmethod
     def _builddefn(cls, defn, args):
         """Parse an alias definition into a tree and marks substitutions
 
         This function marks alias argument references as ``_aliasarg``. The
         parsing rule is provided by ``_parse()``.
 
         ``args`` is a list of alias argument names, or None if the alias
         is declared as a symbol.
 
         >>> parsemap = {
         ...     '$1 or foo': ('or', ('symbol', '$1'), ('symbol', 'foo')),
         ...     '$1 or $bar': ('or', ('symbol', '$1'), ('symbol', '$bar')),
         ...     '$10 or baz': ('or', ('symbol', '$10'), ('symbol', 'baz')),
         ...     '"$1" or "foo"': ('or', ('string', '$1'), ('string', 'foo')),
         ... }
         >>> class aliasrules(basealiasrules):
         ...     _parse = staticmethod(parsemap.__getitem__)
         ...     _trygetfunc = staticmethod(lambda x: None)
         >>> builddefn = aliasrules._builddefn
         >>> def pprint(tree):
         ...     print prettyformat(tree, ('_aliasarg', 'string', 'symbol'))
         >>> args = ['$1', '$2', 'foo']
         >>> pprint(builddefn('$1 or foo', args))
         (or
           ('_aliasarg', '$1')
           ('_aliasarg', 'foo'))
         >>> try:
         ...     builddefn('$1 or $bar', args)
         ... except error.ParseError as inst:
         ...     print parseerrordetail(inst)
         invalid symbol '$bar'
         >>> args = ['$1', '$10', 'foo']
         >>> pprint(builddefn('$10 or baz', args))
         (or
           ('_aliasarg', '$10')
           ('symbol', 'baz'))
         >>> pprint(builddefn('"$1" or "foo"', args))
         (or
           ('string', '$1')
           ('string', 'foo'))
         """
         tree = cls._parse(defn)
         if args:
             args = set(args)
         else:
             args = set()
         return cls._relabelargs(tree, args)
 
     @classmethod
     def build(cls, decl, defn):
         """Parse an alias declaration and definition into an alias object"""
         repl = efmt = None
         name, args, err = cls._builddecl(decl)
         if err:
             efmt = _('bad declaration of %(section)s "%(name)s": %(error)s')
         else:
             try:
                 repl = cls._builddefn(defn, args)
             except error.ParseError as inst:
                 err = parseerrordetail(inst)
                 efmt = _('bad definition of %(section)s "%(name)s": %(error)s')
         if err:
             err = efmt % {'section': cls._section, 'name': name, 'error': err}
         return alias(name, args, err, repl)
 
     @classmethod
     def buildmap(cls, items):
         """Parse a list of alias (name, replacement) pairs into a dict of
         alias objects"""
         aliases = {}
         for decl, defn in items:
             a = cls.build(decl, defn)
             aliases[a.name] = a
         return aliases
 
     @classmethod
     def _getalias(cls, aliases, tree):
         """If tree looks like an unexpanded alias, return (alias, pattern-args)
         pair. Return None otherwise.
         """
         if not isinstance(tree, tuple):
             return None
         if tree[0] == cls._symbolnode:
             name = tree[1]
             a = aliases.get(name)
             if a and a.args is None:
                 return a, None
         func = cls._trygetfunc(tree)
         if func:
             name, args = func
             a = aliases.get(name)
             if a and a.args is not None:
                 return a, args
         return None
 
     @classmethod
     def _expandargs(cls, tree, args):
         """Replace _aliasarg instances with the substitution value of the
         same name in args, recursively.
         """
         if not isinstance(tree, tuple):
             return tree
         if tree[0] == '_aliasarg':
             sym = tree[1]
             return args[sym]
         return tuple(cls._expandargs(t, args) for t in tree)
 
     @classmethod
     def _expand(cls, aliases, tree, expanding, cache):
         if not isinstance(tree, tuple):
             return tree
         r = cls._getalias(aliases, tree)
         if r is None:
             return tuple(cls._expand(aliases, t, expanding, cache)
                          for t in tree)
         a, l = r
         if a.error:
             raise error.Abort(a.error)
         if a in expanding:
             raise error.ParseError(_('infinite expansion of %(section)s '
                                      '"%(name)s" detected')
                                    % {'section': cls._section, 'name': a.name})
         # get cacheable replacement tree by expanding aliases recursively
         expanding.append(a)
         if a.name not in cache:
             cache[a.name] = cls._expand(aliases, a.replacement, expanding,
                                         cache)
         result = cache[a.name]
         expanding.pop()
         if a.args is None:
             return result
         # substitute function arguments in replacement tree
         if len(l) != len(a.args):
             raise error.ParseError(_('invalid number of arguments: %d')
                                    % len(l))
         l = [cls._expand(aliases, t, [], cache) for t in l]
         return cls._expandargs(result, dict(zip(a.args, l)))
 
     @classmethod
     def expand(cls, aliases, tree):
         """Expand aliases in tree, recursively.
 
         'aliases' is a dictionary mapping user defined aliases to alias objects.
         """
         return cls._expand(aliases, tree, [], {})

mercurial/templater.py

@@ -1,1326 +1,1340 b''
 # templater.py - template expansion for output
 #
 # Copyright 2005, 2006 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 from __future__ import absolute_import
 
 import os
 import re
 import types
 
 from .i18n import _
 from . import (
     color,
     config,
     encoding,
     error,
     minirst,
     parser,
     pycompat,
     registrar,
     revset as revsetmod,
     revsetlang,
     templatefilters,
     templatekw,
     util,
 )
 
 # template parsing
 
 elements = {
     # token-type: binding-strength, primary, prefix, infix, suffix
     "(": (20, None, ("group", 1, ")"), ("func", 1, ")"), None),
     "%": (16, None, None, ("%", 16), None),
     "|": (15, None, None, ("|", 15), None),
     "*": (5, None, None, ("*", 5), None),
     "/": (5, None, None, ("/", 5), None),
     "+": (4, None, None, ("+", 4), None),
     "-": (4, None, ("negate", 19), ("-", 4), None),
     "=": (3, None, None, ("keyvalue", 3), None),
     ",": (2, None, None, ("list", 2), None),
     ")": (0, None, None, None, None),
     "integer": (0, "integer", None, None, None),
     "symbol": (0, "symbol", None, None, None),
     "string": (0, "string", None, None, None),
     "template": (0, "template", None, None, None),
     "end": (0, None, None, None, None),
 }
 
 def tokenize(program, start, end, term=None):
     """Parse a template expression into a stream of tokens, which must end
     with term if specified"""
     pos = start
     while pos < end:
         c = program[pos]
         if c.isspace(): # skip inter-token whitespace
             pass
         elif c in "(=,)%|+-*/": # handle simple operators
             yield (c, None, pos)
         elif c in '"\'': # handle quoted templates
             s = pos + 1
             data, pos = _parsetemplate(program, s, end, c)
             yield ('template', data, s)
             pos -= 1
         elif c == 'r' and program[pos:pos + 2] in ("r'", 'r"'):
             # handle quoted strings
             c = program[pos + 1]
             s = pos = pos + 2
             while pos < end: # find closing quote
                 d = program[pos]
                 if d == '\\': # skip over escaped characters
                     pos += 2
                     continue
                 if d == c:
                     yield ('string', program[s:pos], s)
                     break
                 pos += 1
             else:
                 raise error.ParseError(_("unterminated string"), s)
         elif c.isdigit():
             s = pos
             while pos < end:
                 d = program[pos]
                 if not d.isdigit():
                     break
                 pos += 1
             yield ('integer', program[s:pos], s)
             pos -= 1
         elif (c == '\\' and program[pos:pos + 2] in (r"\'", r'\"')
               or c == 'r' and program[pos:pos + 3] in (r"r\'", r'r\"')):
             # handle escaped quoted strings for compatibility with 2.9.2-3.4,
             # where some of nested templates were preprocessed as strings and
             # then compiled. therefore, \"...\" was allowed. (issue4733)
             #
             # processing flow of _evalifliteral() at 5ab28a2e9962:
             # outer template string    -> stringify()  -> compiletemplate()
             # ------------------------    ------------    ------------------
             # {f("\\\\ {g(\"\\\"\")}"}    \\ {g("\"")}    [r'\\', {g("\"")}]
             #             ~~~~~~~~
             #             escaped quoted string
             if c == 'r':
                 pos += 1
                 token = 'string'
             else:
                 token = 'template'
             quote = program[pos:pos + 2]
             s = pos = pos + 2
             while pos < end: # find closing escaped quote
                 if program.startswith('\\\\\\', pos, end):
                     pos += 4 # skip over double escaped characters
                     continue
                 if program.startswith(quote, pos, end):
                     # interpret as if it were a part of an outer string
                     data = parser.unescapestr(program[s:pos])
                     if token == 'template':
                         data = _parsetemplate(data, 0, len(data))[0]
                     yield (token, data, s)
                     pos += 1
                     break
                 pos += 1
             else:
                 raise error.ParseError(_("unterminated string"), s)
         elif c.isalnum() or c in '_':
             s = pos
             pos += 1
             while pos < end: # find end of symbol
                 d = program[pos]
                 if not (d.isalnum() or d == "_"):
                     break
                 pos += 1
             sym = program[s:pos]
             yield ('symbol', sym, s)
             pos -= 1
         elif c == term:
             yield ('end', None, pos + 1)
             return
         else:
             raise error.ParseError(_("syntax error"), pos)
         pos += 1
     if term:
         raise error.ParseError(_("unterminated template expansion"), start)
     yield ('end', None, pos)
 
 def _parsetemplate(tmpl, start, stop, quote=''):
     r"""
     >>> _parsetemplate('foo{bar}"baz', 0, 12)
     ([('string', 'foo'), ('symbol', 'bar'), ('string', '"baz')], 12)
     >>> _parsetemplate('foo{bar}"baz', 0, 12, quote='"')
     ([('string', 'foo'), ('symbol', 'bar')], 9)
     >>> _parsetemplate('foo"{bar}', 0, 9, quote='"')
     ([('string', 'foo')], 4)
     >>> _parsetemplate(r'foo\"bar"baz', 0, 12, quote='"')
     ([('string', 'foo"'), ('string', 'bar')], 9)
     >>> _parsetemplate(r'foo\\"bar', 0, 10, quote='"')
     ([('string', 'foo\\')], 6)
     """
     parsed = []
     sepchars = '{' + quote
     pos = start
     p = parser.parser(elements)
     while pos < stop:
         n = min((tmpl.find(c, pos, stop) for c in sepchars),
                 key=lambda n: (n < 0, n))
         if n < 0:
             parsed.append(('string', parser.unescapestr(tmpl[pos:stop])))
             pos = stop
             break
         c = tmpl[n]
         bs = (n - pos) - len(tmpl[pos:n].rstrip('\\'))
         if bs % 2 == 1:
             # escaped (e.g. '\{', '\\\{', but not '\\{')
             parsed.append(('string', parser.unescapestr(tmpl[pos:n - 1]) + c))
             pos = n + 1
             continue
         if n > pos:
             parsed.append(('string', parser.unescapestr(tmpl[pos:n])))
         if c == quote:
             return parsed, n + 1
 
         parseres, pos = p.parse(tokenize(tmpl, n + 1, stop, '}'))
         parsed.append(parseres)
 
     if quote:
         raise error.ParseError(_("unterminated string"), start)
     return parsed, pos
 
 def _unnesttemplatelist(tree):
     """Expand list of templates to node tuple
 
     >>> def f(tree):
     ...     print prettyformat(_unnesttemplatelist(tree))
     >>> f(('template', []))
     ('string', '')
     >>> f(('template', [('string', 'foo')]))
     ('string', 'foo')
     >>> f(('template', [('string', 'foo'), ('symbol', 'rev')]))
     (template
       ('string', 'foo')
       ('symbol', 'rev'))
     >>> f(('template', [('symbol', 'rev')]))  # template(rev) -> str
     (template
       ('symbol', 'rev'))
     >>> f(('template', [('template', [('string', 'foo')])]))
     ('string', 'foo')
     """
     if not isinstance(tree, tuple):
         return tree
     op = tree[0]
     if op != 'template':
         return (op,) + tuple(_unnesttemplatelist(x) for x in tree[1:])
 
     assert len(tree) == 2
     xs = tuple(_unnesttemplatelist(x) for x in tree[1])
     if not xs:
         return ('string', '')  # empty template ""
     elif len(xs) == 1 and xs[0][0] == 'string':
         return xs[0]  # fast path for string with no template fragment "x"
     else:
         return (op,) + xs
 
 def parse(tmpl):
     """Parse template string into tree"""
     parsed, pos = _parsetemplate(tmpl, 0, len(tmpl))
     assert pos == len(tmpl), 'unquoted template should be consumed'
     return _unnesttemplatelist(('template', parsed))
 
 def _parseexpr(expr):
     """Parse a template expression into tree
 
     >>> _parseexpr('"foo"')
     ('string', 'foo')
     >>> _parseexpr('foo(bar)')
     ('func', ('symbol', 'foo'), ('symbol', 'bar'))
     >>> _parseexpr('foo(')
     Traceback (most recent call last):
       ...
     ParseError: ('not a prefix: end', 4)
     >>> _parseexpr('"foo" "bar"')
     Traceback (most recent call last):
       ...
     ParseError: ('invalid token', 7)
     """
     p = parser.parser(elements)
     tree, pos = p.parse(tokenize(expr, 0, len(expr)))
     if pos != len(expr):
         raise error.ParseError(_('invalid token'), pos)
     return _unnesttemplatelist(tree)
 
 def prettyformat(tree):
     return parser.prettyformat(tree, ('integer', 'string', 'symbol'))
 
 def compileexp(exp, context, curmethods):
     """Compile parsed template tree to (func, data) pair"""
     t = exp[0]
     if t in curmethods:
         return curmethods[t](exp, context)
     raise error.ParseError(_("unknown method '%s'") % t)
 
 # template evaluation
 
 def getsymbol(exp):
     if exp[0] == 'symbol':
         return exp[1]
     raise error.ParseError(_("expected a symbol, got '%s'") % exp[0])
 
 def getlist(x):
     if not x:
         return []
     if x[0] == 'list':
         return getlist(x[1]) + [x[2]]
     return [x]
 
 def gettemplate(exp, context):
     """Compile given template tree or load named template from map file;
     returns (func, data) pair"""
     if exp[0] in ('template', 'string'):
         return compileexp(exp, context, methods)
     if exp[0] == 'symbol':
         # unlike runsymbol(), here 'symbol' is always taken as template name
         # even if it exists in mapping. this allows us to override mapping
         # by web templates, e.g. 'changelogtag' is redefined in map file.
         return context._load(exp[1])
     raise error.ParseError(_("expected template specifier"))
 
 def evalfuncarg(context, mapping, arg):
     func, data = arg
     # func() may return string, generator of strings or arbitrary object such
     # as date tuple, but filter does not want generator.
     thing = func(context, mapping, data)
     if isinstance(thing, types.GeneratorType):
         thing = stringify(thing)
     return thing
 
 def evalboolean(context, mapping, arg):
     """Evaluate given argument as boolean, but also takes boolean literals"""
     func, data = arg
     if func is runsymbol:
         thing = func(context, mapping, data, default=None)
         if thing is None:
             # not a template keyword, takes as a boolean literal
             thing = util.parsebool(data)
     else:
         thing = func(context, mapping, data)
     if isinstance(thing, bool):
         return thing
     # other objects are evaluated as strings, which means 0 is True, but
     # empty dict/list should be False as they are expected to be ''
     return bool(stringify(thing))
 
 def evalinteger(context, mapping, arg, err):
     v = evalfuncarg(context, mapping, arg)
     try:
         return int(v)
     except (TypeError, ValueError):
         raise error.ParseError(err)
 
 def evalstring(context, mapping, arg):
     func, data = arg
     return stringify(func(context, mapping, data))
 
 def evalstringliteral(context, mapping, arg):
     """Evaluate given argument as string template, but returns symbol name
     if it is unknown"""
     func, data = arg
     if func is runsymbol:
         thing = func(context, mapping, data, default=data)
     else:
         thing = func(context, mapping, data)
     return stringify(thing)
 
 def runinteger(context, mapping, data):
     return int(data)
 
 def runstring(context, mapping, data):
     return data
 
 def _recursivesymbolblocker(key):
     def showrecursion(**args):
         raise error.Abort(_("recursive reference '%s' in template") % key)
     return showrecursion
 
 def _runrecursivesymbol(context, mapping, key):
     raise error.Abort(_("recursive reference '%s' in template") % key)
 
 def runsymbol(context, mapping, key, default=''):
     v = mapping.get(key)
     if v is None:
         v = context._defaults.get(key)
     if v is None:
         # put poison to cut recursion. we can't move this to parsing phase
         # because "x = {x}" is allowed if "x" is a keyword. (issue4758)
         safemapping = mapping.copy()
         safemapping[key] = _recursivesymbolblocker(key)
         try:
             v = context.process(key, safemapping)
         except TemplateNotFound:
             v = default
     if callable(v):
         return v(**mapping)
     return v
 
 def buildtemplate(exp, context):
     ctmpl = [compileexp(e, context, methods) for e in exp[1:]]
     return (runtemplate, ctmpl)
 
 def runtemplate(context, mapping, template):
     for func, data in template:
         yield func(context, mapping, data)
 
 def buildfilter(exp, context):
     n = getsymbol(exp[2])
     if n in context._filters:
         filt = context._filters[n]
         arg = compileexp(exp[1], context, methods)
         return (runfilter, (arg, filt))
     if n in funcs:
         f = funcs[n]
         args = _buildfuncargs(exp[1], context, methods, n, f._argspec)
         return (f, args)
     raise error.ParseError(_("unknown function '%s'") % n)
 
 def runfilter(context, mapping, data):
     arg, filt = data
     thing = evalfuncarg(context, mapping, arg)
     try:
         return filt(thing)
     except (ValueError, AttributeError, TypeError):
         if isinstance(arg[1], tuple):
             dt = arg[1][1]
         else:
             dt = arg[1]
         raise error.Abort(_("template filter '%s' is not compatible with "
                            "keyword '%s'") % (filt.func_name, dt))
 
 def buildmap(exp, context):
     func, data = compileexp(exp[1], context, methods)
     tfunc, tdata = gettemplate(exp[2], context)
     return (runmap, (func, data, tfunc, tdata))
 
 def runmap(context, mapping, data):
     func, data, tfunc, tdata = data
     d = func(context, mapping, data)
     if util.safehasattr(d, 'itermaps'):
         diter = d.itermaps()
     else:
         try:
             diter = iter(d)
         except TypeError:
             if func is runsymbol:
                 raise error.ParseError(_("keyword '%s' is not iterable") % data)
             else:
                 raise error.ParseError(_("%r is not iterable") % d)
 
     for i, v in enumerate(diter):
         lm = mapping.copy()
         lm['index'] = i
         if isinstance(v, dict):
             lm.update(v)
             lm['originalnode'] = mapping.get('node')
             yield tfunc(context, lm, tdata)
         else:
             # v is not an iterable of dicts, this happen when 'key'
             # has been fully expanded already and format is useless.
             # If so, return the expanded value.
             yield v
 
 def buildnegate(exp, context):
     arg = compileexp(exp[1], context, exprmethods)
     return (runnegate, arg)
 
 def runnegate(context, mapping, data):
     data = evalinteger(context, mapping, data,
                        _('negation needs an integer argument'))
     return -data
 
 def buildarithmetic(exp, context, func):
     left = compileexp(exp[1], context, exprmethods)
     right = compileexp(exp[2], context, exprmethods)
     return (runarithmetic, (func, left, right))
 
 def runarithmetic(context, mapping, data):
     func, left, right = data
     left = evalinteger(context, mapping, left,
                        _('arithmetic only defined on integers'))
     right = evalinteger(context, mapping, right,
                         _('arithmetic only defined on integers'))
     try:
         return func(left, right)
     except ZeroDivisionError:
         raise error.Abort(_('division by zero is not defined'))
 
 def buildfunc(exp, context):
     n = getsymbol(exp[1])
     if n in funcs:
         f = funcs[n]
         args = _buildfuncargs(exp[2], context, exprmethods, n, f._argspec)
         return (f, args)
     if n in context._filters:
         args = _buildfuncargs(exp[2], context, exprmethods, n, argspec=None)
         if len(args) != 1:
             raise error.ParseError(_("filter %s expects one argument") % n)
         f = context._filters[n]
         return (runfilter, (args[0], f))
     raise error.ParseError(_("unknown function '%s'") % n)
 
 def _buildfuncargs(exp, context, curmethods, funcname, argspec):
     """Compile parsed tree of function arguments into list or dict of
-    (func, data) pairs"""
+    (func, data) pairs
+
+    >>> context = engine(lambda t: (runsymbol, t))
+    >>> def fargs(expr, argspec):
+    ...     x = _parseexpr(expr)
+    ...     n = getsymbol(x[1])
+    ...     return _buildfuncargs(x[2], context, exprmethods, n, argspec)
+    >>> sorted(fargs('a(l=1, k=2)', 'k l m').keys())
+    ['k', 'l']
+    >>> args = fargs('a(opts=1, k=2)', '**opts')
+    >>> args.keys(), sorted(args['opts'].keys())
+    (['opts'], ['k', 'opts'])
+    """
     def compiledict(xs):
         return dict((k, compileexp(x, context, curmethods))
                     for k, x in xs.iteritems())
     def compilelist(xs):
         return [compileexp(x, context, curmethods) for x in xs]
 
     if not argspec:
         # filter or function with no argspec: return list of positional args
         return compilelist(getlist(exp))
 
     # function with argspec: return dict of named args
-    _poskeys, varkey, _keys = argspec = parser.splitargspec(argspec)
+    _poskeys, varkey, _keys, optkey = argspec = parser.splitargspec(argspec)
     treeargs = parser.buildargsdict(getlist(exp), funcname, argspec,
                                     keyvaluenode='keyvalue', keynode='symbol')
     compargs = {}
     if varkey:
         compargs[varkey] = compilelist(treeargs.pop(varkey))
+    if optkey:
+        compargs[optkey] = compiledict(treeargs.pop(optkey))
     compargs.update(compiledict(treeargs))
     return compargs
 
 def buildkeyvaluepair(exp, content):
     raise error.ParseError(_("can't use a key-value pair in this context"))
 
 # dict of template built-in functions
 funcs = {}
 
 templatefunc = registrar.templatefunc(funcs)
 
 @templatefunc('date(date[, fmt])')
 def date(context, mapping, args):
     """Format a date. See :hg:`help dates` for formatting
     strings. The default is a Unix date format, including the timezone:
     "Mon Sep 04 15:13:13 2006 0700"."""
     if not (1 <= len(args) <= 2):
         # i18n: "date" is a keyword
         raise error.ParseError(_("date expects one or two arguments"))
 
     date = evalfuncarg(context, mapping, args[0])
     fmt = None
     if len(args) == 2:
         fmt = evalstring(context, mapping, args[1])
     try:
         if fmt is None:
             return util.datestr(date)
         else:
             return util.datestr(date, fmt)
     except (TypeError, ValueError):
         # i18n: "date" is a keyword
         raise error.ParseError(_("date expects a date information"))
 
 @templatefunc('diff([includepattern [, excludepattern]])')
 def diff(context, mapping, args):
     """Show a diff, optionally
     specifying files to include or exclude."""
     if len(args) > 2:
         # i18n: "diff" is a keyword
         raise error.ParseError(_("diff expects zero, one, or two arguments"))
 
     def getpatterns(i):
         if i < len(args):
             s = evalstring(context, mapping, args[i]).strip()
             if s:
                 return [s]
         return []
 
     ctx = mapping['ctx']
     chunks = ctx.diff(match=ctx.match([], getpatterns(0), getpatterns(1)))
 
     return ''.join(chunks)
 
 @templatefunc('files(pattern)')
 def files(context, mapping, args):
     """All files of the current changeset matching the pattern. See
     :hg:`help patterns`."""
     if not len(args) == 1:
         # i18n: "files" is a keyword
         raise error.ParseError(_("files expects one argument"))
 
     raw = evalstring(context, mapping, args[0])
     ctx = mapping['ctx']
     m = ctx.match([raw])
     files = list(ctx.matches(m))
     return templatekw.showlist("file", files, **mapping)
 
 @templatefunc('fill(text[, width[, initialident[, hangindent]]])')
 def fill(context, mapping, args):
     """Fill many
     paragraphs with optional indentation. See the "fill" filter."""
     if not (1 <= len(args) <= 4):
         # i18n: "fill" is a keyword
         raise error.ParseError(_("fill expects one to four arguments"))
 
     text = evalstring(context, mapping, args[0])
     width = 76
     initindent = ''
     hangindent = ''
     if 2 <= len(args) <= 4:
         width = evalinteger(context, mapping, args[1],
                             # i18n: "fill" is a keyword
                             _("fill expects an integer width"))
         try:
             initindent = evalstring(context, mapping, args[2])
             hangindent = evalstring(context, mapping, args[3])
         except IndexError:
             pass
 
     return templatefilters.fill(text, width, initindent, hangindent)
 
 @templatefunc('formatnode(node)')
 def formatnode(context, mapping, args):
     """Obtain the preferred form of a changeset hash. (DEPRECATED)"""
     if len(args) != 1:
         # i18n: "formatnode" is a keyword
         raise error.ParseError(_("formatnode expects one argument"))
 
     ui = mapping['ui']
     node = evalstring(context, mapping, args[0])
     if ui.debugflag:
         return node
     return templatefilters.short(node)
 
 @templatefunc('pad(text, width[, fillchar=\' \'[, left=False]])',
               argspec='text width fillchar left')
 def pad(context, mapping, args):
     """Pad text with a
     fill character."""
     if 'text' not in args or 'width' not in args:
         # i18n: "pad" is a keyword
         raise error.ParseError(_("pad() expects two to four arguments"))
 
     width = evalinteger(context, mapping, args['width'],
                         # i18n: "pad" is a keyword
                         _("pad() expects an integer width"))
 
     text = evalstring(context, mapping, args['text'])
 
     left = False
     fillchar = ' '
     if 'fillchar' in args:
         fillchar = evalstring(context, mapping, args['fillchar'])
         if len(color.stripeffects(fillchar)) != 1:
             # i18n: "pad" is a keyword
             raise error.ParseError(_("pad() expects a single fill character"))
     if 'left' in args:
         left = evalboolean(context, mapping, args['left'])
 
     fillwidth = width - encoding.colwidth(color.stripeffects(text))
     if fillwidth <= 0:
         return text
     if left:
         return fillchar * fillwidth + text
     else:
         return text + fillchar * fillwidth
 
 @templatefunc('indent(text, indentchars[, firstline])')
 def indent(context, mapping, args):
     """Indents all non-empty lines
     with the characters given in the indentchars string. An optional
     third parameter will override the indent for the first line only
     if present."""
     if not (2 <= len(args) <= 3):
         # i18n: "indent" is a keyword
         raise error.ParseError(_("indent() expects two or three arguments"))
 
     text = evalstring(context, mapping, args[0])
     indent = evalstring(context, mapping, args[1])
 
     if len(args) == 3:
         firstline = evalstring(context, mapping, args[2])
     else:
         firstline = indent
 
     # the indent function doesn't indent the first line, so we do it here
     return templatefilters.indent(firstline + text, indent)
 
 @templatefunc('get(dict, key)')
 def get(context, mapping, args):
     """Get an attribute/key from an object. Some keywords
     are complex types. This function allows you to obtain the value of an
     attribute on these types."""
     if len(args) != 2:
         # i18n: "get" is a keyword
         raise error.ParseError(_("get() expects two arguments"))
 
     dictarg = evalfuncarg(context, mapping, args[0])
     if not util.safehasattr(dictarg, 'get'):
         # i18n: "get" is a keyword
         raise error.ParseError(_("get() expects a dict as first argument"))
 
     key = evalfuncarg(context, mapping, args[1])
     return dictarg.get(key)
 
 @templatefunc('if(expr, then[, else])')
 def if_(context, mapping, args):
     """Conditionally execute based on the result of
     an expression."""
     if not (2 <= len(args) <= 3):
         # i18n: "if" is a keyword
         raise error.ParseError(_("if expects two or three arguments"))
 
     test = evalboolean(context, mapping, args[0])
     if test:
         yield args[1][0](context, mapping, args[1][1])
     elif len(args) == 3:
         yield args[2][0](context, mapping, args[2][1])
 
 @templatefunc('ifcontains(needle, haystack, then[, else])')
 def ifcontains(context, mapping, args):
     """Conditionally execute based
     on whether the item "needle" is in "haystack"."""
     if not (3 <= len(args) <= 4):
         # i18n: "ifcontains" is a keyword
         raise error.ParseError(_("ifcontains expects three or four arguments"))
 
     needle = evalstring(context, mapping, args[0])
     haystack = evalfuncarg(context, mapping, args[1])
 
     if needle in haystack:
         yield args[2][0](context, mapping, args[2][1])
     elif len(args) == 4:
         yield args[3][0](context, mapping, args[3][1])
 
 @templatefunc('ifeq(expr1, expr2, then[, else])')
 def ifeq(context, mapping, args):
     """Conditionally execute based on
     whether 2 items are equivalent."""
     if not (3 <= len(args) <= 4):
         # i18n: "ifeq" is a keyword
         raise error.ParseError(_("ifeq expects three or four arguments"))
 
     test = evalstring(context, mapping, args[0])
     match = evalstring(context, mapping, args[1])
     if test == match:
         yield args[2][0](context, mapping, args[2][1])
     elif len(args) == 4:
         yield args[3][0](context, mapping, args[3][1])
 
 @templatefunc('join(list, sep)')
 def join(context, mapping, args):
     """Join items in a list with a delimiter."""
     if not (1 <= len(args) <= 2):
         # i18n: "join" is a keyword
         raise error.ParseError(_("join expects one or two arguments"))
 
     joinset = args[0][0](context, mapping, args[0][1])
     if util.safehasattr(joinset, 'itermaps'):
         jf = joinset.joinfmt
         joinset = [jf(x) for x in joinset.itermaps()]
 
     joiner = " "
     if len(args) > 1:
         joiner = evalstring(context, mapping, args[1])
 
     first = True
     for x in joinset:
         if first:
             first = False
         else:
             yield joiner
         yield x
 
 @templatefunc('label(label, expr)')
 def label(context, mapping, args):
     """Apply a label to generated content. Content with
     a label applied can result in additional post-processing, such as
     automatic colorization."""
     if len(args) != 2:
         # i18n: "label" is a keyword
         raise error.ParseError(_("label expects two arguments"))
 
     ui = mapping['ui']
     thing = evalstring(context, mapping, args[1])
     # preserve unknown symbol as literal so effects like 'red', 'bold',
     # etc. don't need to be quoted
     label = evalstringliteral(context, mapping, args[0])
 
     return ui.label(thing, label)
 
 @templatefunc('latesttag([pattern])')
 def latesttag(context, mapping, args):
     """The global tags matching the given pattern on the
     most recent globally tagged ancestor of this changeset.
     If no such tags exist, the "{tag}" template resolves to
     the string "null"."""
     if len(args) > 1:
         # i18n: "latesttag" is a keyword
         raise error.ParseError(_("latesttag expects at most one argument"))
 
     pattern = None
     if len(args) == 1:
         pattern = evalstring(context, mapping, args[0])
 
     return templatekw.showlatesttags(pattern, **mapping)
 
 @templatefunc('localdate(date[, tz])')
 def localdate(context, mapping, args):
     """Converts a date to the specified timezone.
     The default is local date."""
     if not (1 <= len(args) <= 2):
         # i18n: "localdate" is a keyword
         raise error.ParseError(_("localdate expects one or two arguments"))
 
     date = evalfuncarg(context, mapping, args[0])
     try:
         date = util.parsedate(date)
     except AttributeError:  # not str nor date tuple
         # i18n: "localdate" is a keyword
         raise error.ParseError(_("localdate expects a date information"))
     if len(args) >= 2:
         tzoffset = None
         tz = evalfuncarg(context, mapping, args[1])
         if isinstance(tz, str):
             tzoffset, remainder = util.parsetimezone(tz)
             if remainder:
                 tzoffset = None
         if tzoffset is None:
             try:
                 tzoffset = int(tz)
             except (TypeError, ValueError):
                 # i18n: "localdate" is a keyword
                 raise error.ParseError(_("localdate expects a timezone"))
     else:
         tzoffset = util.makedate()[1]
     return (date[0], tzoffset)
 
 @templatefunc('mod(a, b)')
 def mod(context, mapping, args):
     """Calculate a mod b such that a / b + a mod b == a"""
     if not len(args) == 2:
         # i18n: "mod" is a keyword
         raise error.ParseError(_("mod expects two arguments"))
 
     func = lambda a, b: a % b
     return runarithmetic(context, mapping, (func, args[0], args[1]))
 
 @templatefunc('relpath(path)')
 def relpath(context, mapping, args):
     """Convert a repository-absolute path into a filesystem path relative to
     the current working directory."""
     if len(args) != 1:
         # i18n: "relpath" is a keyword
         raise error.ParseError(_("relpath expects one argument"))
 
     repo = mapping['ctx'].repo()
     path = evalstring(context, mapping, args[0])
     return repo.pathto(path)
 
 @templatefunc('revset(query[, formatargs...])')
 def revset(context, mapping, args):
     """Execute a revision set query. See
     :hg:`help revset`."""
     if not len(args) > 0:
         # i18n: "revset" is a keyword
         raise error.ParseError(_("revset expects one or more arguments"))
 
     raw = evalstring(context, mapping, args[0])
     ctx = mapping['ctx']
     repo = ctx.repo()
 
     def query(expr):
         m = revsetmod.match(repo.ui, expr)
         return m(repo)
 
     if len(args) > 1:
         formatargs = [evalfuncarg(context, mapping, a) for a in args[1:]]
         revs = query(revsetlang.formatspec(raw, *formatargs))
         revs = list(revs)
     else:
         revsetcache = mapping['cache'].setdefault("revsetcache", {})
         if raw in revsetcache:
             revs = revsetcache[raw]
         else:
             revs = query(raw)
             revs = list(revs)
             revsetcache[raw] = revs
 
     return templatekw.showrevslist("revision", revs, **mapping)
 
 @templatefunc('rstdoc(text, style)')
 def rstdoc(context, mapping, args):
     """Format reStructuredText."""
     if len(args) != 2:
         # i18n: "rstdoc" is a keyword
         raise error.ParseError(_("rstdoc expects two arguments"))
 
     text = evalstring(context, mapping, args[0])
     style = evalstring(context, mapping, args[1])
 
     return minirst.format(text, style=style, keep=['verbose'])
 
 @templatefunc('separate(sep, args)', argspec='sep *args')
 def separate(context, mapping, args):
     """Add a separator between non-empty arguments."""
     if 'sep' not in args:
         # i18n: "separate" is a keyword
         raise error.ParseError(_("separate expects at least one argument"))
 
     sep = evalstring(context, mapping, args['sep'])
     first = True
     for arg in args['args']:
         argstr = evalstring(context, mapping, arg)
         if not argstr:
             continue
         if first:
             first = False
         else:
             yield sep
         yield argstr
 
 @templatefunc('shortest(node, minlength=4)')
 def shortest(context, mapping, args):
     """Obtain the shortest representation of
     a node."""
     if not (1 <= len(args) <= 2):
         # i18n: "shortest" is a keyword
         raise error.ParseError(_("shortest() expects one or two arguments"))
 
     node = evalstring(context, mapping, args[0])
 
     minlength = 4
     if len(args) > 1:
         minlength = evalinteger(context, mapping, args[1],
                                 # i18n: "shortest" is a keyword
                                 _("shortest() expects an integer minlength"))
 
     # _partialmatch() of filtered changelog could take O(len(repo)) time,
     # which would be unacceptably slow. so we look for hash collision in
     # unfiltered space, which means some hashes may be slightly longer.
     cl = mapping['ctx']._repo.unfiltered().changelog
     def isvalid(test):
         try:
             if cl._partialmatch(test) is None:
                 return False
 
             try:
                 i = int(test)
                 # if we are a pure int, then starting with zero will not be
                 # confused as a rev; or, obviously, if the int is larger than
                 # the value of the tip rev
                 if test[0] == '0' or i > len(cl):
                     return True
                 return False
             except ValueError:
                 return True
         except error.RevlogError:
             return False
 
     shortest = node
     startlength = max(6, minlength)
     length = startlength
     while True:
         test = node[:length]
         if isvalid(test):
             shortest = test
             if length == minlength or length > startlength:
                 return shortest
             length -= 1
         else:
             length += 1
             if len(shortest) <= length:
                 return shortest
 
 @templatefunc('strip(text[, chars])')
 def strip(context, mapping, args):
     """Strip characters from a string. By default,
     strips all leading and trailing whitespace."""
     if not (1 <= len(args) <= 2):
         # i18n: "strip" is a keyword
         raise error.ParseError(_("strip expects one or two arguments"))
 
     text = evalstring(context, mapping, args[0])
     if len(args) == 2:
         chars = evalstring(context, mapping, args[1])
         return text.strip(chars)
     return text.strip()
 
 @templatefunc('sub(pattern, replacement, expression)')
 def sub(context, mapping, args):
     """Perform text substitution
     using regular expressions."""
     if len(args) != 3:
         # i18n: "sub" is a keyword
         raise error.ParseError(_("sub expects three arguments"))
 
     pat = evalstring(context, mapping, args[0])
     rpl = evalstring(context, mapping, args[1])
     src = evalstring(context, mapping, args[2])
     try:
         patre = re.compile(pat)
     except re.error:
         # i18n: "sub" is a keyword
         raise error.ParseError(_("sub got an invalid pattern: %s") % pat)
     try:
         yield patre.sub(rpl, src)
     except re.error:
         # i18n: "sub" is a keyword
         raise error.ParseError(_("sub got an invalid replacement: %s") % rpl)
 
 @templatefunc('startswith(pattern, text)')
 def startswith(context, mapping, args):
     """Returns the value from the "text" argument
     if it begins with the content from the "pattern" argument."""
     if len(args) != 2:
         # i18n: "startswith" is a keyword
         raise error.ParseError(_("startswith expects two arguments"))
 
     patn = evalstring(context, mapping, args[0])
     text = evalstring(context, mapping, args[1])
     if text.startswith(patn):
         return text
     return ''
 
 @templatefunc('word(number, text[, separator])')
 def word(context, mapping, args):
     """Return the nth word from a string."""
     if not (2 <= len(args) <= 3):
         # i18n: "word" is a keyword
         raise error.ParseError(_("word expects two or three arguments, got %d")
                                % len(args))
 
     num = evalinteger(context, mapping, args[0],
                       # i18n: "word" is a keyword
                       _("word expects an integer index"))
     text = evalstring(context, mapping, args[1])
     if len(args) == 3:
         splitter = evalstring(context, mapping, args[2])
     else:
         splitter = None
 
     tokens = text.split(splitter)
     if num >= len(tokens) or num < -len(tokens):
         return ''
     else:
         return tokens[num]
 
 # methods to interpret function arguments or inner expressions (e.g. {_(x)})
 exprmethods = {
     "integer": lambda e, c: (runinteger, e[1]),
     "string": lambda e, c: (runstring, e[1]),
     "symbol": lambda e, c: (runsymbol, e[1]),
     "template": buildtemplate,
     "group": lambda e, c: compileexp(e[1], c, exprmethods),
 #    ".": buildmember,
     "|": buildfilter,
     "%": buildmap,
     "func": buildfunc,
     "keyvalue": buildkeyvaluepair,
     "+": lambda e, c: buildarithmetic(e, c, lambda a, b: a + b),
     "-": lambda e, c: buildarithmetic(e, c, lambda a, b: a - b),
     "negate": buildnegate,
     "*": lambda e, c: buildarithmetic(e, c, lambda a, b: a * b),
     "/": lambda e, c: buildarithmetic(e, c, lambda a, b: a // b),
     }
 
 # methods to interpret top-level template (e.g. {x}, {x|_}, {x % "y"})
 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
 
 def _flatten(thing):
     '''yield a single stream from a possibly nested set of iterators'''
     thing = templatekw.unwraphybrid(thing)
     if isinstance(thing, str):
         yield thing
     elif thing is None:
         pass
     elif not util.safehasattr(thing, '__iter__'):
         yield str(thing)
     else:
         for i in thing:
             i = templatekw.unwraphybrid(i)
             if isinstance(i, str):
                 yield i
             elif i is None:
                 pass
             elif not util.safehasattr(i, '__iter__'):
                 yield str(i)
             else:
                 for j in _flatten(i):
                     yield j
 
 def unquotestring(s):
     '''unwrap quotes if any; otherwise returns unmodified string'''
     if len(s) < 2 or s[0] not in "'\"" or s[0] != s[-1]:
         return s
     return s[1:-1]
 
 class engine(object):
     '''template expansion engine.
 
     template expansion works like this. a map file contains key=value
     pairs. if value is quoted, it is treated as string. otherwise, it
     is treated as name of template file.
 
     templater is asked to expand a key in map. it looks up key, and
     looks for strings like this: {foo}. it expands {foo} by looking up
     foo in map, and substituting it. expansion is recursive: it stops
     when there is no more {foo} to replace.
 
     expansion also allows formatting and filtering.
 
     format uses key to expand each item in list. syntax is
     {key%format}.
 
     filter uses function to transform value. syntax is
     {key|filter1|filter2|...}.'''
 
     def __init__(self, loader, filters=None, defaults=None, aliases=()):
         self._loader = loader
         if filters is None:
             filters = {}
         self._filters = filters
         if defaults is None:
             defaults = {}
         self._defaults = defaults
         self._aliasmap = _aliasrules.buildmap(aliases)
         self._cache = {}  # key: (func, data)
 
     def _load(self, t):
         '''load, parse, and cache a template'''
         if t not in self._cache:
             # put poison to cut recursion while compiling 't'
             self._cache[t] = (_runrecursivesymbol, t)
             try:
                 x = parse(self._loader(t))
                 if self._aliasmap:
                     x = _aliasrules.expand(self._aliasmap, x)
                 self._cache[t] = compileexp(x, self, methods)
             except: # re-raises
                 del self._cache[t]
                 raise
         return self._cache[t]
 
     def process(self, t, mapping):
         '''Perform expansion. t is name of map element to expand.
         mapping contains added elements for use during expansion. Is a
         generator.'''
         func, data = self._load(t)
         return _flatten(func(self, mapping, data))
 
 engines = {'default': engine}
 
 def stylelist():
     paths = templatepaths()
     if not paths:
         return _('no templates found, try `hg debuginstall` for more info')
     dirlist = os.listdir(paths[0])
     stylelist = []
     for file in dirlist:
         split = file.split(".")
         if split[-1] in ('orig', 'rej'):
             continue
         if split[0] == "map-cmdline":
             stylelist.append(split[1])
     return ", ".join(sorted(stylelist))
 
 def _readmapfile(mapfile):
     """Load template elements from the given map file"""
     if not os.path.exists(mapfile):
         raise error.Abort(_("style '%s' not found") % mapfile,
                           hint=_("available styles: %s") % stylelist())
 
     base = os.path.dirname(mapfile)
     conf = config.config(includepaths=templatepaths())
     conf.read(mapfile)
 
     cache = {}
     tmap = {}
     for key, val in conf[''].items():
         if not val:
             raise error.ParseError(_('missing value'), conf.source('', key))
         if val[0] in "'\"":
             if val[0] != val[-1]:
                 raise error.ParseError(_('unmatched quotes'),
                                        conf.source('', key))
             cache[key] = unquotestring(val)
         elif key == "__base__":
             # treat as a pointer to a base class for this style
             path = util.normpath(os.path.join(base, val))
 
             # fallback check in template paths
             if not os.path.exists(path):
                 for p in templatepaths():
                     p2 = util.normpath(os.path.join(p, val))
                     if os.path.isfile(p2):
                         path = p2
                         break
                     p3 = util.normpath(os.path.join(p2, "map"))
                     if os.path.isfile(p3):
                         path = p3
                         break
 
             bcache, btmap = _readmapfile(path)
             for k in bcache:
                 if k not in cache:
                     cache[k] = bcache[k]
             for k in btmap:
                 if k not in tmap:
                     tmap[k] = btmap[k]
         else:
             val = 'default', val
             if ':' in val[1]:
                 val = val[1].split(':', 1)
             tmap[key] = val[0], os.path.join(base, val[1])
     return cache, tmap
 
 class TemplateNotFound(error.Abort):
     pass
 
 class templater(object):
 
     def __init__(self, filters=None, defaults=None, cache=None, aliases=(),
                  minchunk=1024, maxchunk=65536):
         '''set up template engine.
         filters is dict of functions. each transforms a value into another.
         defaults is dict of default map definitions.
         aliases is list of alias (name, replacement) pairs.
         '''
         if filters is None:
             filters = {}
         if defaults is None:
             defaults = {}
         if cache is None:
             cache = {}
         self.cache = cache.copy()
         self.map = {}
         self.filters = templatefilters.filters.copy()
         self.filters.update(filters)
         self.defaults = defaults
         self._aliases = aliases
         self.minchunk, self.maxchunk = minchunk, maxchunk
         self.ecache = {}
 
     @classmethod
     def frommapfile(cls, mapfile, filters=None, defaults=None, cache=None,
                     minchunk=1024, maxchunk=65536):
         """Create templater from the specified map file"""
         t = cls(filters, defaults, cache, [], minchunk, maxchunk)
         cache, tmap = _readmapfile(mapfile)
         t.cache.update(cache)
         t.map = tmap
         return t
 
     def __contains__(self, key):
         return key in self.cache or key in self.map
 
     def load(self, t):
         '''Get the template for the given template name. Use a local cache.'''
         if t not in self.cache:
             try:
                 self.cache[t] = util.readfile(self.map[t][1])
             except KeyError as inst:
                 raise TemplateNotFound(_('"%s" not in template map') %
                                        inst.args[0])
             except IOError as inst:
                 raise IOError(inst.args[0], _('template file %s: %s') %
                               (self.map[t][1], inst.args[1]))
         return self.cache[t]
 
     def __call__(self, t, **mapping):
         ttype = t in self.map and self.map[t][0] or 'default'
         if ttype not in self.ecache:
             try:
                 ecls = engines[ttype]
             except KeyError:
                 raise error.Abort(_('invalid template engine: %s') % ttype)
             self.ecache[ttype] = ecls(self.load, self.filters, self.defaults,
                                       self._aliases)
         proc = self.ecache[ttype]
 
         stream = proc.process(t, mapping)
         if self.minchunk:
             stream = util.increasingchunks(stream, min=self.minchunk,
                                            max=self.maxchunk)
         return stream
 
 def templatepaths():
     '''return locations used for template files.'''
     pathsrel = ['templates']
     paths = [os.path.normpath(os.path.join(util.datapath, f))
              for f in pathsrel]
     return [p for p in paths if os.path.isdir(p)]
 
 def templatepath(name):
     '''return location of template file. returns None if not found.'''
     for p in templatepaths():
         f = os.path.join(p, name)
         if os.path.exists(f):
             return f
     return None
 
 def stylemap(styles, paths=None):
     """Return path to mapfile for a given style.
 
     Searches mapfile in the following locations:
     1. templatepath/style/map
     2. templatepath/map-style
     3. templatepath/map
     """
 
     if paths is None:
         paths = templatepaths()
     elif isinstance(paths, str):
         paths = [paths]
 
     if isinstance(styles, str):
         styles = [styles]
 
     for style in styles:
         # only plain name is allowed to honor template paths
         if (not style
             or style in (os.curdir, os.pardir)
             or pycompat.ossep in style
             or pycompat.osaltsep and pycompat.osaltsep in style):
             continue
         locations = [os.path.join(style, 'map'), 'map-' + style]
         locations.append('map')
 
         for path in paths:
             for location in locations:
                 mapfile = os.path.join(path, location)
                 if os.path.isfile(mapfile):
                     return style, mapfile
 
     raise RuntimeError("No hgweb templates found in %r" % paths)
 
 def loadfunction(ui, extname, registrarobj):
     """Load template function from specified registrarobj
     """
     for name, func in registrarobj._table.iteritems():
         funcs[name] = func
 
 # tell hggettext to extract docstrings from these functions:
 i18nfunctions = funcs.values()