revsets: let p1() and p2() return parents of working dir

This patch makes the 'set' argument to revset functions p1() and p2()
optional. If no argument is given, p1() and p2() return the first or second
parent of the working directory.

If the working directory is not an in-progress merge (no 2nd parent), p2()
returns the empty set. For a checkout of the null changeset, both p1() and
p2() return the empty set.

tests/test-revset-dirstate-parents.t

@@ -0,0 +1,42 b''
+  $ HGENCODING=utf-8
+  $ export HGENCODING
+
+  $ try() {
+  >   hg debugrevspec --debug $@
+  > }
+
+  $ log() {
+  >   hg log --template '{rev}\n' -r "$1"
+  > }
+
+  $ hg init repo
+  $ cd repo
+
+  $ try 'p1()'
+  ('func', ('symbol', 'p1'), None)
+  -1
+  $ try 'p2()'
+  ('func', ('symbol', 'p2'), None)
+
+null revision
+  $ log 'p1()'
+  $ log 'p2()'
+
+working dir with a single parent
+  $ echo a > a
+  $ hg ci -Aqm0
+  $ log 'p1()'
+  0
+  $ log 'p2()'
+
+merge in progress
+  $ echo b > b
+  $ hg ci -Aqm1
+  $ hg up -q 0
+  $ echo c > c
+  $ hg ci -Aqm2
+  $ hg merge -q
+  $ log 'p1()'
+  2
+  $ log 'p2()'
+  1

mercurial/revset.py

@@ -1,797 +1,807 b''
 # revset.py - revision set queries 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.
 
 import re
 import parser, util, error, discovery
 import match as matchmod
 from i18n import _, gettext
 
 elements = {
     "(": (20, ("group", 1, ")"), ("func", 1, ")")),
     "-": (5, ("negate", 19), ("minus", 5)),
     "::": (17, ("dagrangepre", 17), ("dagrange", 17),
            ("dagrangepost", 17)),
     "..": (17, ("dagrangepre", 17), ("dagrange", 17),
            ("dagrangepost", 17)),
     ":": (15, ("rangepre", 15), ("range", 15), ("rangepost", 15)),
     "not": (10, ("not", 10)),
     "!": (10, ("not", 10)),
     "and": (5, None, ("and", 5)),
     "&": (5, None, ("and", 5)),
     "or": (4, None, ("or", 4)),
     "|": (4, None, ("or", 4)),
     "+": (4, None, ("or", 4)),
     ",": (2, None, ("list", 2)),
     ")": (0, None, None),
     "symbol": (0, ("symbol",), None),
     "string": (0, ("string",), None),
     "end": (0, None, None),
 }
 
 keywords = set(['and', 'or', 'not'])
 
 def tokenize(program):
     pos, l = 0, len(program)
     while pos < l:
         c = program[pos]
         if c.isspace(): # skip inter-token whitespace
             pass
         elif c == ':' and program[pos:pos + 2] == '::': # look ahead carefully
             yield ('::', None, pos)
             pos += 1 # skip ahead
         elif c == '.' and program[pos:pos + 2] == '..': # look ahead carefully
             yield ('..', None, pos)
             pos += 1 # skip ahead
         elif c in "():,-|&+!": # handle simple operators
             yield (c, None, pos)
         elif (c in '"\'' or c == 'r' and
               program[pos:pos + 2] in ("r'", 'r"')): # handle quoted strings
             if c == 'r':
                 pos += 1
                 c = program[pos]
                 decode = lambda x: x
             else:
                 decode = lambda x: x.decode('string-escape')
             pos += 1
             s = pos
             while pos < l: # find closing quote
                 d = program[pos]
                 if d == '\\': # skip over escaped characters
                     pos += 2
                     continue
                 if d == c:
                     yield ('string', decode(program[s:pos]), s)
                     break
                 pos += 1
             else:
                 raise error.ParseError(_("unterminated string"), s)
         elif c.isalnum() or c in '._' or ord(c) > 127: # gather up a symbol/keyword
             s = pos
             pos += 1
             while pos < l: # find end of symbol
                 d = program[pos]
                 if not (d.isalnum() or d in "._" or ord(d) > 127):
                     break
                 if d == '.' and program[pos - 1] == '.': # special case for ..
                     pos -= 1
                     break
                 pos += 1
             sym = program[s:pos]
             if sym in keywords: # operator keywords
                 yield (sym, None, s)
             else:
                 yield ('symbol', sym, s)
             pos -= 1
         else:
             raise error.ParseError(_("syntax error"), pos)
         pos += 1
     yield ('end', None, pos)
 
 # helpers
 
 def getstring(x, err):
     if x and (x[0] == 'string' or x[0] == 'symbol'):
         return x[1]
     raise error.ParseError(err)
 
 def getlist(x):
     if not x:
         return []
     if x[0] == 'list':
         return getlist(x[1]) + [x[2]]
     return [x]
 
 def getargs(x, min, max, err):
     l = getlist(x)
     if len(l) < min or len(l) > max:
         raise error.ParseError(err)
     return l
 
 def getset(repo, subset, x):
     if not x:
         raise error.ParseError(_("missing argument"))
     return methods[x[0]](repo, subset, *x[1:])
 
 # operator methods
 
 def stringset(repo, subset, x):
     x = repo[x].rev()
     if x == -1 and len(subset) == len(repo):
         return [-1]
     if x in subset:
         return [x]
     return []
 
 def symbolset(repo, subset, x):
     if x in symbols:
         raise error.ParseError(_("can't use %s here") % x)
     return stringset(repo, subset, x)
 
 def rangeset(repo, subset, x, y):
     m = getset(repo, subset, x)
     if not m:
         m = getset(repo, range(len(repo)), x)
 
     n = getset(repo, subset, y)
     if not n:
         n = getset(repo, range(len(repo)), y)
 
     if not m or not n:
         return []
     m, n = m[0], n[-1]
 
     if m < n:
         r = range(m, n + 1)
     else:
         r = range(m, n - 1, -1)
     s = set(subset)
     return [x for x in r if x in s]
 
 def andset(repo, subset, x, y):
     return getset(repo, getset(repo, subset, x), y)
 
 def orset(repo, subset, x, y):
     s = set(getset(repo, subset, x))
     s |= set(getset(repo, [r for r in subset if r not in s], y))
     return [r for r in subset if r in s]
 
 def notset(repo, subset, x):
     s = set(getset(repo, subset, x))
     return [r for r in subset if r not in s]
 
 def listset(repo, subset, a, b):
     raise error.ParseError(_("can't use a list in this context"))
 
 def func(repo, subset, a, b):
     if a[0] == 'symbol' and a[1] in symbols:
         return symbols[a[1]](repo, subset, b)
     raise error.ParseError(_("not a function: %s") % a[1])
 
 # functions
 
 def node(repo, subset, x):
     """``id(string)``
     Revision non-ambiguously specified by the given hex string prefix.
     """
     # i18n: "id" is a keyword
     l = getargs(x, 1, 1, _("id requires one argument"))
     # i18n: "id" is a keyword
     n = getstring(l[0], _("id requires a string"))
     if len(n) == 40:
         rn = repo[n].rev()
     else:
         rn = repo.changelog.rev(repo.changelog._partialmatch(n))
     return [r for r in subset if r == rn]
 
 def rev(repo, subset, x):
     """``rev(number)``
     Revision with the given numeric identifier.
     """
     # i18n: "rev" is a keyword
     l = getargs(x, 1, 1, _("rev requires one argument"))
     try:
         # i18n: "rev" is a keyword
         l = int(getstring(l[0], _("rev requires a number")))
     except ValueError:
         # i18n: "rev" is a keyword
         raise error.ParseError(_("rev expects a number"))
     return [r for r in subset if r == l]
 
 def p1(repo, subset, x):
-    """``p1(set)``
-    First parent of changesets in set.
+    """``p1([set])``
+    First parent of changesets in set, or the working directory.
     """
+    if x is None:
+        return [repo[x].parents()[0].rev()]
+
     ps = set()
     cl = repo.changelog
     for r in getset(repo, range(len(repo)), x):
         ps.add(cl.parentrevs(r)[0])
     return [r for r in subset if r in ps]
 
 def p2(repo, subset, x):
-    """``p2(set)``
-    Second parent of changesets in set.
+    """``p2([set])``
+    Second parent of changesets in set, or the working directory.
     """
+    if x is None:
+        ps = repo[x].parents()
+        try:
+            return [ps[1].rev()]
+        except IndexError:
+            return []
+
     ps = set()
     cl = repo.changelog
     for r in getset(repo, range(len(repo)), x):
         ps.add(cl.parentrevs(r)[1])
     return [r for r in subset if r in ps]
 
 def parents(repo, subset, x):
     """``parents(set)``
     The set of all parents for all changesets in set.
     """
     ps = set()
     cl = repo.changelog
     for r in getset(repo, range(len(repo)), x):
         ps.update(cl.parentrevs(r))
     return [r for r in subset if r in ps]
 
 def maxrev(repo, subset, x):
     """``max(set)``
     Changeset with highest revision number in set.
     """
     s = getset(repo, subset, x)
     if s:
         m = max(s)
         if m in subset:
             return [m]
     return []
 
 def minrev(repo, subset, x):
     """``min(set)``
     Changeset with lowest revision number in set.
     """
     s = getset(repo, subset, x)
     if s:
         m = min(s)
         if m in subset:
             return [m]
     return []
 
 def limit(repo, subset, x):
     """``limit(set, n)``
     First n members of set.
     """
     # i18n: "limit" is a keyword
     l = getargs(x, 2, 2, _("limit requires two arguments"))
     try:
         # i18n: "limit" is a keyword
         lim = int(getstring(l[1], _("limit requires a number")))
     except ValueError:
         # i18n: "limit" is a keyword
         raise error.ParseError(_("limit expects a number"))
     return getset(repo, subset, l[0])[:lim]
 
 def children(repo, subset, x):
     """``children(set)``
     Child changesets of changesets in set.
     """
     cs = set()
     cl = repo.changelog
     s = set(getset(repo, range(len(repo)), x))
     for r in xrange(0, len(repo)):
         for p in cl.parentrevs(r):
             if p in s:
                 cs.add(r)
     return [r for r in subset if r in cs]
 
 def branch(repo, subset, x):
     """``branch(set)``
     All changesets belonging to the branches of changesets in set.
     """
     s = getset(repo, range(len(repo)), x)
     b = set()
     for r in s:
         b.add(repo[r].branch())
     s = set(s)
     return [r for r in subset if r in s or repo[r].branch() in b]
 
 def ancestor(repo, subset, x):
     """``ancestor(single, single)``
     Greatest common ancestor of the two changesets.
     """
     # i18n: "ancestor" is a keyword
     l = getargs(x, 2, 2, _("ancestor requires two arguments"))
     r = range(len(repo))
     a = getset(repo, r, l[0])
     b = getset(repo, r, l[1])
     if len(a) != 1 or len(b) != 1:
         # i18n: "ancestor" is a keyword
         raise error.ParseError(_("ancestor arguments must be single revisions"))
     an = [repo[a[0]].ancestor(repo[b[0]]).rev()]
 
     return [r for r in an if r in subset]
 
 def ancestors(repo, subset, x):
     """``ancestors(set)``
     Changesets that are ancestors of a changeset in set.
     """
     args = getset(repo, range(len(repo)), x)
     if not args:
         return []
     s = set(repo.changelog.ancestors(*args)) | set(args)
     return [r for r in subset if r in s]
 
 def descendants(repo, subset, x):
     """``descendants(set)``
     Changesets which are descendants of changesets in set.
     """
     args = getset(repo, range(len(repo)), x)
     if not args:
         return []
     s = set(repo.changelog.descendants(*args)) | set(args)
     return [r for r in subset if r in s]
 
 def follow(repo, subset, x):
     """``follow()``
     An alias for ``::.`` (ancestors of the working copy's first parent).
     """
     # i18n: "follow" is a keyword
     getargs(x, 0, 0, _("follow takes no arguments"))
     p = repo['.'].rev()
     s = set(repo.changelog.ancestors(p)) | set([p])
     return [r for r in subset if r in s]
 
 def date(repo, subset, x):
     """``date(interval)``
     Changesets within the interval, see :hg:`help dates`.
     """
     # i18n: "date" is a keyword
     ds = getstring(x, _("date requires a string"))
     dm = util.matchdate(ds)
     return [r for r in subset if dm(repo[r].date()[0])]
 
 def keyword(repo, subset, x):
     """``keyword(string)``
     Search commit message, user name, and names of changed files for
     string.
     """
     # i18n: "keyword" is a keyword
     kw = getstring(x, _("keyword requires a string")).lower()
     l = []
     for r in subset:
         c = repo[r]
         t = " ".join(c.files() + [c.user(), c.description()])
         if kw in t.lower():
             l.append(r)
     return l
 
 def grep(repo, subset, x):
     """``grep(regex)``
     Like ``keyword(string)`` but accepts a regex. Use ``grep(r'...')``
     to ensure special escape characters are handled correctly.
     """
     try:
         # i18n: "grep" is a keyword
         gr = re.compile(getstring(x, _("grep requires a string")))
     except re.error, e:
         raise error.ParseError(_('invalid match pattern: %s') % e)
     l = []
     for r in subset:
         c = repo[r]
         for e in c.files() + [c.user(), c.description()]:
             if gr.search(e):
                 l.append(r)
                 continue
     return l
 
 def author(repo, subset, x):
     """``author(string)``
     Alias for ``user(string)``.
     """
     # i18n: "author" is a keyword
     n = getstring(x, _("author requires a string")).lower()
     return [r for r in subset if n in repo[r].user().lower()]
 
 def user(repo, subset, x):
     """``user(string)``
     User name is string.
     """
     return author(repo, subset, x)
 
 def hasfile(repo, subset, x):
     """``file(pattern)``
     Changesets affecting files matched by pattern.
     """
     # i18n: "file" is a keyword
     pat = getstring(x, _("file requires a pattern"))
     m = matchmod.match(repo.root, repo.getcwd(), [pat])
     s = []
     for r in subset:
         for f in repo[r].files():
             if m(f):
                 s.append(r)
                 continue
     return s
 
 def contains(repo, subset, x):
     """``contains(pattern)``
     Revision contains pattern.
     """
     # i18n: "contains" is a keyword
     pat = getstring(x, _("contains requires a pattern"))
     m = matchmod.match(repo.root, repo.getcwd(), [pat])
     s = []
     if m.files() == [pat]:
         for r in subset:
             if pat in repo[r]:
                 s.append(r)
                 continue
     else:
         for r in subset:
             for f in repo[r].manifest():
                 if m(f):
                     s.append(r)
                     continue
     return s
 
 def checkstatus(repo, subset, pat, field):
     m = matchmod.match(repo.root, repo.getcwd(), [pat])
     s = []
     fast = (m.files() == [pat])
     for r in subset:
         c = repo[r]
         if fast:
             if pat not in c.files():
                 continue
         else:
             for f in c.files():
                 if m(f):
                     break
             else:
                 continue
         files = repo.status(c.p1().node(), c.node())[field]
         if fast:
             if pat in files:
                 s.append(r)
                 continue
         else:
             for f in files:
                 if m(f):
                     s.append(r)
                     continue
     return s
 
 def modifies(repo, subset, x):
     """``modifies(pattern)``
     Changesets modifying files matched by pattern.
     """
     # i18n: "modifies" is a keyword
     pat = getstring(x, _("modifies requires a pattern"))
     return checkstatus(repo, subset, pat, 0)
 
 def adds(repo, subset, x):
     """``adds(pattern)``
     Changesets that add a file matching pattern.
     """
     # i18n: "adds" is a keyword
     pat = getstring(x, _("adds requires a pattern"))
     return checkstatus(repo, subset, pat, 1)
 
 def removes(repo, subset, x):
     """``removes(pattern)``
     Changesets which remove files matching pattern.
     """
     # i18n: "removes" is a keyword
     pat = getstring(x, _("removes requires a pattern"))
     return checkstatus(repo, subset, pat, 2)
 
 def merge(repo, subset, x):
     """``merge()``
     Changeset is a merge changeset.
     """
     # i18n: "merge" is a keyword
     getargs(x, 0, 0, _("merge takes no arguments"))
     cl = repo.changelog
     return [r for r in subset if cl.parentrevs(r)[1] != -1]
 
 def closed(repo, subset, x):
     """``closed()``
     Changeset is closed.
     """
     # i18n: "closed" is a keyword
     getargs(x, 0, 0, _("closed takes no arguments"))
     return [r for r in subset if repo[r].extra().get('close')]
 
 def head(repo, subset, x):
     """``head()``
     Changeset is a named branch head.
     """
     # i18n: "head" is a keyword
     getargs(x, 0, 0, _("head takes no arguments"))
     hs = set()
     for b, ls in repo.branchmap().iteritems():
         hs.update(repo[h].rev() for h in ls)
     return [r for r in subset if r in hs]
 
 def reverse(repo, subset, x):
     """``reverse(set)``
     Reverse order of set.
     """
     l = getset(repo, subset, x)
     l.reverse()
     return l
 
 def present(repo, subset, x):
     """``present(set)``
     An empty set, if any revision in set isn't found; otherwise,
     all revisions in set.
     """
     try:
         return getset(repo, subset, x)
     except error.RepoLookupError:
         return []
 
 def sort(repo, subset, x):
     """``sort(set[, [-]key...])``
     Sort set by keys. The default sort order is ascending, specify a key
     as ``-key`` to sort in descending order.
 
     The keys can be:
 
     - ``rev`` for the revision number,
     - ``branch`` for the branch name,
     - ``desc`` for the commit message (description),
     - ``user`` for user name (``author`` can be used as an alias),
     - ``date`` for the commit date
     """
     # i18n: "sort" is a keyword
     l = getargs(x, 1, 2, _("sort requires one or two arguments"))
     keys = "rev"
     if len(l) == 2:
         keys = getstring(l[1], _("sort spec must be a string"))
 
     s = l[0]
     keys = keys.split()
     l = []
     def invert(s):
         return "".join(chr(255 - ord(c)) for c in s)
     for r in getset(repo, subset, s):
         c = repo[r]
         e = []
         for k in keys:
             if k == 'rev':
                 e.append(r)
             elif k == '-rev':
                 e.append(-r)
             elif k == 'branch':
                 e.append(c.branch())
             elif k == '-branch':
                 e.append(invert(c.branch()))
             elif k == 'desc':
                 e.append(c.description())
             elif k == '-desc':
                 e.append(invert(c.description()))
             elif k in 'user author':
                 e.append(c.user())
             elif k in '-user -author':
                 e.append(invert(c.user()))
             elif k == 'date':
                 e.append(c.date()[0])
             elif k == '-date':
                 e.append(-c.date()[0])
             else:
                 raise error.ParseError(_("unknown sort key %r") % k)
         e.append(r)
         l.append(e)
     l.sort()
     return [e[-1] for e in l]
 
 def getall(repo, subset, x):
     """``all()``
     All changesets, the same as ``0:tip``.
     """
     # i18n: "all" is a keyword
     getargs(x, 0, 0, _("all takes no arguments"))
     return subset
 
 def heads(repo, subset, x):
     """``heads(set)``
     Members of set with no children in set.
     """
     s = getset(repo, subset, x)
     ps = set(parents(repo, subset, x))
     return [r for r in s if r not in ps]
 
 def roots(repo, subset, x):
     """``roots(set)``
     Changesets with no parent changeset in set.
     """
     s = getset(repo, subset, x)
     cs = set(children(repo, subset, x))
     return [r for r in s if r not in cs]
 
 def outgoing(repo, subset, x):
     """``outgoing([path])``
     Changesets not found in the specified destination repository, or the
     default push location.
     """
     import hg # avoid start-up nasties
     # i18n: "outgoing" is a keyword
     l = getargs(x, 0, 1, _("outgoing requires a repository path"))
     # i18n: "outgoing" is a keyword
     dest = l and getstring(l[0], _("outgoing requires a repository path")) or ''
     dest = repo.ui.expandpath(dest or 'default-push', dest or 'default')
     dest, branches = hg.parseurl(dest)
     revs, checkout = hg.addbranchrevs(repo, repo, branches, [])
     if revs:
         revs = [repo.lookup(rev) for rev in revs]
     other = hg.repository(hg.remoteui(repo, {}), dest)
     repo.ui.pushbuffer()
     o = discovery.findoutgoing(repo, other)
     repo.ui.popbuffer()
     cl = repo.changelog
     o = set([cl.rev(r) for r in repo.changelog.nodesbetween(o, revs)[0]])
     return [r for r in subset if r in o]
 
 def tag(repo, subset, x):
     """``tag(name)``
     The specified tag by name, or all tagged revisions if no name is given.
     """
     # i18n: "tag" is a keyword
     args = getargs(x, 0, 1, _("tag takes one or no arguments"))
     cl = repo.changelog
     if args:
         tn = getstring(args[0],
                        # i18n: "tag" is a keyword
                        _('the argument to tag must be a string'))
         s = set([cl.rev(n) for t, n in repo.tagslist() if t == tn])
     else:
         s = set([cl.rev(n) for t, n in repo.tagslist() if t != 'tip'])
     return [r for r in subset if r in s]
 
 def tagged(repo, subset, x):
     return tag(repo, subset, x)
 
 symbols = {
     "adds": adds,
     "all": getall,
     "ancestor": ancestor,
     "ancestors": ancestors,
     "author": author,
     "branch": branch,
     "children": children,
     "closed": closed,
     "contains": contains,
     "date": date,
     "descendants": descendants,
     "file": hasfile,
     "follow": follow,
     "grep": grep,
     "head": head,
     "heads": heads,
     "keyword": keyword,
     "limit": limit,
     "max": maxrev,
     "min": minrev,
     "merge": merge,
     "modifies": modifies,
     "id": node,
     "outgoing": outgoing,
     "p1": p1,
     "p2": p2,
     "parents": parents,
     "present": present,
     "removes": removes,
     "reverse": reverse,
     "rev": rev,
     "roots": roots,
     "sort": sort,
     "tag": tag,
     "tagged": tagged,
     "user": user,
 }
 
 methods = {
     "range": rangeset,
     "string": stringset,
     "symbol": symbolset,
     "and": andset,
     "or": orset,
     "not": notset,
     "list": listset,
     "func": func,
 }
 
 def optimize(x, small):
     if x == None:
         return 0, x
 
     smallbonus = 1
     if small:
         smallbonus = .5
 
     op = x[0]
     if op == 'minus':
         return optimize(('and', x[1], ('not', x[2])), small)
     elif op == 'dagrange':
         return optimize(('and', ('func', ('symbol', 'descendants'), x[1]),
                          ('func', ('symbol', 'ancestors'), x[2])), small)
     elif op == 'dagrangepre':
         return optimize(('func', ('symbol', 'ancestors'), x[1]), small)
     elif op == 'dagrangepost':
         return optimize(('func', ('symbol', 'descendants'), x[1]), small)
     elif op == 'rangepre':
         return optimize(('range', ('string', '0'), x[1]), small)
     elif op == 'rangepost':
         return optimize(('range', x[1], ('string', 'tip')), small)
     elif op == 'negate':
         return optimize(('string',
                          '-' + getstring(x[1], _("can't negate that"))), small)
     elif op in 'string symbol negate':
         return smallbonus, x # single revisions are small
     elif op == 'and' or op == 'dagrange':
         wa, ta = optimize(x[1], True)
         wb, tb = optimize(x[2], True)
         w = min(wa, wb)
         if wa > wb:
             return w, (op, tb, ta)
         return w, (op, ta, tb)
     elif op == 'or':
         wa, ta = optimize(x[1], False)
         wb, tb = optimize(x[2], False)
         if wb < wa:
             wb, wa = wa, wb
         return max(wa, wb), (op, ta, tb)
     elif op == 'not':
         o = optimize(x[1], not small)
         return o[0], (op, o[1])
     elif op == 'group':
         return optimize(x[1], small)
     elif op in 'range list':
         wa, ta = optimize(x[1], small)
         wb, tb = optimize(x[2], small)
         return wa + wb, (op, ta, tb)
     elif op == 'func':
         f = getstring(x[1], _("not a symbol"))
         wa, ta = optimize(x[2], small)
         if f in "grep date user author keyword branch file outgoing":
             w = 10 # slow
         elif f in "modifies adds removes":
             w = 30 # slower
         elif f == "contains":
             w = 100 # very slow
         elif f == "ancestor":
             w = 1 * smallbonus
         elif f == "reverse limit":
             w = 0
         elif f in "sort":
             w = 10 # assume most sorts look at changelog
         else:
             w = 1
         return w + wa, (op, x[1], ta)
     return 1, x
 
 parse = parser.parser(tokenize, elements).parse
 
 def match(spec):
     if not spec:
         raise error.ParseError(_("empty query"))
     tree = parse(spec)
     weight, tree = optimize(tree, True)
     def mfunc(repo, subset):
         return getset(repo, subset, tree)
     return mfunc
 
 def makedoc(topic, doc):
     """Generate and include predicates help in revsets topic."""
     predicates = []
     for name in sorted(symbols):
         text = symbols[name].__doc__
         if not text:
             continue
         text = gettext(text.rstrip())
         lines = text.splitlines()
         lines[1:] = [('  ' + l.strip()) for l in lines[1:]]
         predicates.append('\n'.join(lines))
     predicates = '\n\n'.join(predicates)
     doc = doc.replace('.. predicatesmarker', predicates)
     return doc
 
 # tell hggettext to extract docstrings from these functions:
 i18nfunctions = symbols.values()