fileset: add kind:pat operator ":" isn't taken as a symbol character but an infix operator so we can write e.g. "path:'foo bar'" as well as "'path:foo bar'". An invalid pattern kind is rejected in the former form as we know a kind is specified explicitly. The binding strength is copied from "x:y" range operator of revset. Perhaps it can be adjusted later if we want to parse "foo:bar()" as "(foo:bar)()", not "foo:(bar())". We can also add "kind:" postfix operator if we want. One possible confusion is that the scope of the leading "set:" vs "kind:pat" operator. The former is consumed by a matcher so applies to the whole fileset expression: $ hg files 'set:foo() or kind:bar or baz' ^^^^^^^^^^^^^^^^^^^^^^^^ Whereas the scope of kind:pat operator is narrow: $ hg files 'set:foo() or kind:bar or baz' ^^^

--- a/mercurial/help/filesets.txt	Sun Jan 14 13:33:56 2018 +0900
+++ b/mercurial/help/filesets.txt	Sun Jan 14 13:29:15 2018 +0900
@@ -9,7 +9,8 @@
 or double quotes if they contain characters outside of
 ``[.*{}[]?/\_a-zA-Z0-9\x80-\xff]`` or if they match one of the
 predefined predicates. This generally applies to file patterns other
-than globs and arguments for predicates.
+than globs and arguments for predicates. Pattern prefixes such as
+``path:`` may be specified without quoting.
 
 Special characters can be used in quoted identifiers by escaping them,
 e.g., ``\n`` is interpreted as a newline. To prevent them from being
@@ -75,4 +76,4 @@
 
 - Remove files listed in foo.lst that contain the letter a or b::
 
-    hg remove "set: 'listfile:foo.lst' and (**a* or **b*)"
+    hg remove "set: listfile:foo.lst and (**a* or **b*)"