Author: lwall
Date: 2009-06-08 17:27:48 +0200 (Mon, 08 Jun 2009)
New Revision: 27034
Modified:
docs/Perl6/Spec/S03-operators.pod
Log:
[S03] reduce prececedence of adverbs from inside comma to inside item_assignment
Modified: docs/Perl6/Spec/S03-operators.pod
===================================================================
--- docs/Perl6/Spec/S03-operators.pod 2009-06-08 15:20:31 UTC (rev 27033)
+++ docs/Perl6/Spec/S03-operators.pod 2009-06-08 15:27:48 UTC (rev 27034)
@@ -13,8 +13,8 @@
Maintainer: Larry Wall <la...@wall.org>
Date: 8 Mar 2004
- Last Modified: 24 May 2009
- Version: 166
+ Last Modified: 7 Jun 2009
+ Version: 167
=head1 Overview
@@ -1342,6 +1342,54 @@
=back
+=head1 Adverbs
+
+Operator adverbs
+are parsed as trailing unary operators at this precedence level,
+just tighter than item assignment. (They're not officially "postfix" operators
+because those require the absense of whitespace, and these allow whitespace.
+These adverbs insert themselves in the spot where the parser is
+expecting an infix operator, but the parser continues to look for
+an infix after parsing the adverb and applying it to the previous
+term.) Thus,
+
+ $a < 1 and $b == 2 :carefully
+
+does the C<==> carefully, while
+
+ $a < 1 && $b == 2 :carefully
+
+does the C<&&> carefully because C<&&> is of
+tighter precedence than "comma". Use
+
+ $a < 1 && ($b == 2 :carefully)
+
+to apply the adverb to the C<==> operator instead. We say that
+C<==> is the "topmost" operator in the sense that it is at the
+top of the parse tree that the adverb could possibly apply to.
+(It could not apply outside the parens.) If you are unsure
+what the topmost operator is, just ask yourself which operator
+would be applied last. For instance, in
+
+ +%hash{$key} :foo
+
+The subscript happens first and the C<+> operator happens last,
+so C<:foo> would apply to that. Use
+
+ +(%hash{$key} :foo)
+
+to apply C<:foo> to the subscripting operator instead.
+
+Adverbs will generally attach the way you want when you say things like
+
+ 1 .. $x+2 :by(2)
+
+The proposed internal testing syntax makes use of these precedence rules:
+
+ $x eqv $y+2 :ok<$x is equivalent to $y+2>;
+
+Here the adverb is considered to be modifying the C<eqv> operator.
+
=head2 Item assignment precedence
=over
@@ -1442,60 +1490,6 @@
=back
-While the preceding are parsed as prefix operators, operator adverbs
-are parsed as trailing unary operators at this precedence level,
-just tighter than comma. (They're not officially "postfix" operators
-because those require the absense of whitespace, and these allow whitespace.
-These adverbs insert themselves in the spot where the parser is
-expecting an infix operator, but the parser continues to look for
-an infix after parsing the adverb and applying it to the previous
-term.) Thus,
-
- $a < 1 and $b == 2 :carefully
-
-does the C<==> carefully, while
-
- $a < 1 && $b == 2 :carefully
-
-does the C<&&> carefully because C<&&> is of
-tighter precedence than "comma". Use
-
- $a < 1 && ($b == 2 :carefully)
-
-to apply the adverb to the C<==> operator instead. We say that
-C<==> is the "topmost" operator in the sense that it is at the
-top of the parse tree that the adverb could possibly apply to.
-(It could not apply outside the parens.) If you are unsure
-what the topmost operator is, just ask yourself which operator
-would be applied last. For instance, in
-
- +%hash{$key} :foo
-
-The subscript happens first and the C<+> operator happens last,
-so C<:foo> would apply to that. Use
-
- +(%hash{$key} :foo)
-
-to apply C<:foo> to the subscripting operator instead. Likewise
-
- $x = 1..10:by(2)
-
-will apply the adverb to the item assignment (and fail), but since
-
- @x = 1..10:by(2)
-
-is a (looser) list assignment, the adverb applies to the range operator
-as expected. And in general note that adverbs will attach the way
-you want when you say things like
-
- 1 .. $x+2 :by(2)
-
-The new internal testing syntax makes use of these precedence rules:
-
- $x eqv $y+2 :ok<$x is equivalent to $y+2>;
-
-Here the adverb is considered to be modifying the C<eqv> operator.
-
=head2 Comma operator precedence
=over
