fileset: use decorator to mark a function as fileset predicate

Using decorator can localize changes for adding (or removing) a
fileset predicate function in source code.

It is also useful to pick predicates up for specific purpose. For
example, subsequent patches marks predicates as "call status" or "use
existing" via decorator.

To avoid (1) redundancy between "predicate name" and (the beginning
of) help document, and (2) accidental typo of help document, this
patch also makes decorator put predicate declration into the beginning
of help.

mercurial/fileset.py

@@ -130,54 +130,79 b' def minusset(mctx, x, y):'
 def listset(mctx, a, b):
     raise error.ParseError(_("can't use a list in this context"))
 
+# symbols are callable like:
+#  fun(mctx, x)
+# with:
+#  mctx - current matchctx instance
+#  x - argument in tree form
+symbols = {}
+
+def predicate(decl):
+    """Return a decorator for fileset predicate function
+
+    'decl' argument is the declaration (including argument list like
+    'adds(pattern)') or the name (for internal use only) of predicate.
+    """
+    def decorator(func):
+        i = decl.find('(')
+        if i > 0:
+            name = decl[:i]
+        else:
+            name = decl
+        symbols[name] = func
+        if func.__doc__:
+            func.__doc__ = "``%s``\n    %s" % (decl, func.__doc__.strip())
+        return func
+    return decorator
+
+@predicate('modified()')
 def modified(mctx, x):
-    """``modified()``
-    File that is modified according to :hg:`status`.
+    """File that is modified according to :hg:`status`.
     """
     # i18n: "modified" is a keyword
     getargs(x, 0, 0, _("modified takes no arguments"))
     s = mctx.status().modified
     return [f for f in mctx.subset if f in s]
 
+@predicate('added()')
 def added(mctx, x):
-    """``added()``
-    File that is added according to :hg:`status`.
+    """File that is added according to :hg:`status`.
     """
     # i18n: "added" is a keyword
     getargs(x, 0, 0, _("added takes no arguments"))
     s = mctx.status().added
     return [f for f in mctx.subset if f in s]
 
+@predicate('removed()')
 def removed(mctx, x):
-    """``removed()``
-    File that is removed according to :hg:`status`.
+    """File that is removed according to :hg:`status`.
     """
     # i18n: "removed" is a keyword
     getargs(x, 0, 0, _("removed takes no arguments"))
     s = mctx.status().removed
     return [f for f in mctx.subset if f in s]
 
+@predicate('deleted()')
 def deleted(mctx, x):
-    """``deleted()``
-    Alias for ``missing()``.
+    """Alias for ``missing()``.
     """
     # i18n: "deleted" is a keyword
     getargs(x, 0, 0, _("deleted takes no arguments"))
     s = mctx.status().deleted
     return [f for f in mctx.subset if f in s]
 
+@predicate('missing()')
 def missing(mctx, x):
-    """``missing()``
-    File that is missing according to :hg:`status`.
+    """File that is missing according to :hg:`status`.
     """
     # i18n: "missing" is a keyword
     getargs(x, 0, 0, _("missing takes no arguments"))
     s = mctx.status().deleted
     return [f for f in mctx.subset if f in s]
 
+@predicate('unknown()')
 def unknown(mctx, x):
-    """``unknown()``
-    File that is unknown according to :hg:`status`. These files will only be
+    """File that is unknown according to :hg:`status`. These files will only be
     considered if this predicate is used.
     """
     # i18n: "unknown" is a keyword
@@ -185,9 +210,9 b' def unknown(mctx, x):'
     s = mctx.status().unknown
     return [f for f in mctx.subset if f in s]
 
+@predicate('ignored()')
 def ignored(mctx, x):
-    """``ignored()``
-    File that is ignored according to :hg:`status`. These files will only be
+    """File that is ignored according to :hg:`status`. These files will only be
     considered if this predicate is used.
     """
     # i18n: "ignored" is a keyword
@@ -195,9 +220,9 b' def ignored(mctx, x):'
     s = mctx.status().ignored
     return [f for f in mctx.subset if f in s]
 
+@predicate('clean()')
 def clean(mctx, x):
-    """``clean()``
-    File that is clean according to :hg:`status`.
+    """File that is clean according to :hg:`status`.
     """
     # i18n: "clean" is a keyword
     getargs(x, 0, 0, _("clean takes no arguments"))
@@ -226,33 +251,33 b' def getargs(x, min, max, err):'
         raise error.ParseError(err)
     return l
 
+@predicate('binary()')
 def binary(mctx, x):
-    """``binary()``
-    File that appears to be binary (contains NUL bytes).
+    """File that appears to be binary (contains NUL bytes).
     """
     # i18n: "binary" is a keyword
     getargs(x, 0, 0, _("binary takes no arguments"))
     return [f for f in mctx.existing() if util.binary(mctx.ctx[f].data())]
 
+@predicate('exec()')
 def exec_(mctx, x):
-    """``exec()``
-    File that is marked as executable.
+    """File that is marked as executable.
     """
     # i18n: "exec" is a keyword
     getargs(x, 0, 0, _("exec takes no arguments"))
     return [f for f in mctx.existing() if mctx.ctx.flags(f) == 'x']
 
+@predicate('symlink()')
 def symlink(mctx, x):
-    """``symlink()``
-    File that is marked as a symlink.
+    """File that is marked as a symlink.
     """
     # i18n: "symlink" is a keyword
     getargs(x, 0, 0, _("symlink takes no arguments"))
     return [f for f in mctx.existing() if mctx.ctx.flags(f) == 'l']
 
+@predicate('resolved()')
 def resolved(mctx, x):
-    """``resolved()``
-    File that is marked resolved according to :hg:`resolve -l`.
+    """File that is marked resolved according to :hg:`resolve -l`.
     """
     # i18n: "resolved" is a keyword
     getargs(x, 0, 0, _("resolved takes no arguments"))
@@ -261,9 +286,9 b' def resolved(mctx, x):'
     ms = merge.mergestate.read(mctx.ctx.repo())
     return [f for f in mctx.subset if f in ms and ms[f] == 'r']
 
+@predicate('unresolved()')
 def unresolved(mctx, x):
-    """``unresolved()``
-    File that is marked unresolved according to :hg:`resolve -l`.
+    """File that is marked unresolved according to :hg:`resolve -l`.
     """
     # i18n: "unresolved" is a keyword
     getargs(x, 0, 0, _("unresolved takes no arguments"))
@@ -272,18 +297,18 b' def unresolved(mctx, x):'
     ms = merge.mergestate.read(mctx.ctx.repo())
     return [f for f in mctx.subset if f in ms and ms[f] == 'u']
 
+@predicate('hgignore()')
 def hgignore(mctx, x):
-    """``hgignore()``
-    File that matches the active .hgignore pattern.
+    """File that matches the active .hgignore pattern.
     """
     # i18n: "hgignore" is a keyword
     getargs(x, 0, 0, _("hgignore takes no arguments"))
     ignore = mctx.ctx.repo().dirstate._ignore
     return [f for f in mctx.subset if ignore(f)]
 
+@predicate('portable()')
 def portable(mctx, x):
-    """``portable()``
-    File that has a portable name. (This doesn't include filenames with case
+    """File that has a portable name. (This doesn't include filenames with case
     collisions.)
     """
     # i18n: "portable" is a keyword
@@ -291,9 +316,9 b' def portable(mctx, x):'
     checkwinfilename = util.checkwinfilename
     return [f for f in mctx.subset if checkwinfilename(f) is None]
 
+@predicate('grep(regex)')
 def grep(mctx, x):
-    """``grep(regex)``
-    File contains the given regular expression.
+    """File contains the given regular expression.
     """
     try:
         # i18n: "grep" is a keyword
@@ -318,9 +343,9 b' def _sizetomax(s):'
     except ValueError:
         raise error.ParseError(_("couldn't parse size: %s") % s)
 
+@predicate('size(expression)')
 def size(mctx, x):
-    """``size(expression)``
-    File size matches the given expression. Examples:
+    """File size matches the given expression. Examples:
 
     - 1k (files from 1024 to 2047 bytes)
     - < 20k (files less than 20480 bytes)
@@ -356,9 +381,9 b' def size(mctx, x):'
 
     return [f for f in mctx.existing() if m(mctx.ctx[f].size())]
 
+@predicate('encoding(name)')
 def encoding(mctx, x):
-    """``encoding(name)``
-    File can be successfully decoded with the given character
+    """File can be successfully decoded with the given character
     encoding. May not be useful for encodings other than ASCII and
     UTF-8.
     """
@@ -379,9 +404,9 b' def encoding(mctx, x):'
 
     return s
 
+@predicate('eol(style)')
 def eol(mctx, x):
-    """``eol(style)``
-    File contains newlines of the given style (dos, unix, mac). Binary
+    """File contains newlines of the given style (dos, unix, mac). Binary
     files are excluded, files with mixed line endings match multiple
     styles.
     """
@@ -402,9 +427,9 b' def eol(mctx, x):'
             s.append(f)
     return s
 
+@predicate('copied()')
 def copied(mctx, x):
-    """``copied()``
-    File that is recorded as being copied.
+    """File that is recorded as being copied.
     """
     # i18n: "copied" is a keyword
     getargs(x, 0, 0, _("copied takes no arguments"))
@@ -415,9 +440,9 b' def copied(mctx, x):'
             s.append(f)
     return s
 
+@predicate('subrepo([pattern])')
 def subrepo(mctx, x):
-    """``subrepo([pattern])``
-    Subrepositories whose paths match the given pattern.
+    """Subrepositories whose paths match the given pattern.
     """
     # i18n: "subrepo" is a keyword
     getargs(x, 0, 1, _("subrepo takes at most one argument"))
@@ -438,30 +463,6 b' def subrepo(mctx, x):'
     else:
         return [sub for sub in sstate]
 
-symbols = {
-    'added': added,
-    'binary': binary,
-    'clean': clean,
-    'copied': copied,
-    'deleted': deleted,
-    'encoding': encoding,
-    'eol': eol,
-    'exec': exec_,
-    'grep': grep,
-    'ignored': ignored,
-    'hgignore': hgignore,
-    'missing': missing,
-    'modified': modified,
-    'portable': portable,
-    'removed': removed,
-    'resolved': resolved,
-    'size': size,
-    'symlink': symlink,
-    'unknown': unknown,
-    'unresolved': unresolved,
-    'subrepo': subrepo,
-}
-
 methods = {
     'string': stringset,
     'symbol': stringset,