Author: lwall
Date: 2009-04-10 02:44:36 +0200 (Fri, 10 Apr 2009)
New Revision: 26167
Modified:
docs/Perl6/Spec/S02-bits.pod
docs/Perl6/Spec/S03-operators.pod
docs/Perl6/Spec/S06-routines.pod
Log:
Eliminate listop forms of sigils.
Modified: docs/Perl6/Spec/S02-bits.pod
===================================================================
--- docs/Perl6/Spec/S02-bits.pod 2009-04-09 23:27:43 UTC (rev 26166)
+++ docs/Perl6/Spec/S02-bits.pod 2009-04-10 00:44:36 UTC (rev 26167)
@@ -12,9 +12,9 @@
Maintainer: Larry Wall <la...@wall.org>
Date: 10 Aug 2004
- Last Modified: 22 Mar 2009
+ Last Modified: 9 Apr 2009
Number: 2
- Version: 161
+ Version: 162
This document summarizes Apocalypse 2, which covers small-scale
lexical items and typological issues. (These Synopses also contain
@@ -1783,12 +1783,6 @@
print $( foo() ) # foo called in item context
print @@( foo() ) # foo called in slice context
-The bare sigil is parsed as a list operator in rvalue context, so
-these mean the same thing:
-
- print $ foo() # foo called in item context
- print @@ foo() # foo called in slice context
-
In declarative contexts bare sigils may be used as placeholders for
anonymous variables:
@@ -1799,6 +1793,13 @@
($a, *, $c) = 1..3;
+Attempts to say something like:
+
+ ($a, $, $c) = 1..3;
+
+will result in the message, "Anonymous variable requires declarator".
+
+
=item *
Ordinary package-qualified names look like in Perl 5:
Modified: docs/Perl6/Spec/S03-operators.pod
===================================================================
--- docs/Perl6/Spec/S03-operators.pod 2009-04-09 23:27:43 UTC (rev 26166)
+++ docs/Perl6/Spec/S03-operators.pod 2009-04-10 00:44:36 UTC (rev 26167)
@@ -12,9 +12,9 @@
Maintainer: Larry Wall <la...@wall.org>
Date: 8 Mar 2004
- Last Modified: 18 Mar 2009
+ Last Modified: 9 Apr 2009
Number: 3
- Version: 160
+ Version: 161
=head1 Overview
@@ -1944,26 +1944,32 @@
@@ slice
% hash
-As listops, these look like terms from the left, but raise their
-precedence on the right sufficiently to govern list infix
-operators:
+These may only be used as functions with explicit parens:
- $ 1,2 Z 3,4 # [\(1,3),\(2,4)]
- @ 1,2 Z 3,4 # 1,3,2,4
- @@ 1,2 Z 3,4 # [1,3],[2,4]
- % 1,2 Z 3,4 # { 1 => 3, 2 => 4 }
+ $(1,2 Z 3,4) # [\(1,3),\(2,4)]
+ @(1,2 Z 3,4) # 1,3,2,4
+ @@(1,2 Z 3,4) # [1,3],[2,4]
+ %(1,2 Z 3,4) # { 1 => 3, 2 => 4 }
- $ 1,2 X 3,4 # [\(1,3),\(1,4),\(2,3),\(2,4)]
- @ 1,2 X 3,4 # 1,3,1,4,2,3,2,4
- @@ 1,2 X 3,4 # [1,3],[1,4],[2,3],[2,4]
+ $(1,2 X 3,4) # [\(1,3),\(1,4),\(2,3),\(2,4)]
+ @(1,2 X 3,4) # 1,3,1,4,2,3,2,4
+ @@(1,2 X 3,4) # [1,3],[1,4],[2,3],[2,4]
These can also influence the result of functions that returns lists of
captures:
- $ map { $_, $_*2 }, ^4 # [\(0,0),\(1,2),\(2,4),\(3,6)]
- @ map { $_, $_*2 }, ^4 # 0,0,1,2,2,4,3,6
- @@ map { $_, $_*2 }, ^4 # [0,0],[1,2],[2,4],[3,6]
- % map { $_, $_*2 }, ^4 # { 0 => 0, 1 => 2, 2 => 4, 3 => 6 }
+ $(map { $_, $_*2 }, ^4) # [\(0,0),\(1,2),\(2,4),\(3,6)]
+ @(map { $_, $_*2 }, ^4) # 0,0,1,2,2,4,3,6
+ @@(map { $_, $_*2 }, ^4) # [0,0],[1,2],[2,4],[3,6]
+ %(map { $_, $_*2 }, ^4) # { 0 => 0, 1 => 2, 2 => 4, 3 => 6 }
+The parens may not be omitted on the sigiled forms, but the alpha variants may
+be used as normal listops:
+
+ item map { $_, $_*2 }, ^4 # [\(0,0),\(1,2),\(2,4),\(3,6)]
+ list map { $_, $_*2 }, ^4 # 0,0,1,2,2,4,3,6
+ slice map { $_, $_*2 }, ^4 # [0,0],[1,2],[2,4],[3,6]
+ hash map { $_, $_*2 }, ^4 # { 0 => 0, 1 => 2, 2 => 4, 3 => 6 }
+
=item *
The C<item> contextualizer
@@ -2210,9 +2216,10 @@
Perl 5's C<${...}>, C<@{...}>, C<%{...}>, etc. dereferencing
forms are now C<$(...)>, C<@(...)>, C<%(...)>, etc. instead.
-Listop-like forms use the bare sigil following by whitespace.
-Use of the Perl 5 curly forms will result in an error message
-pointing the user to the new forms.
+(Use of the Perl 5 curly forms will result in an error message
+pointing the user to the new forms.)
+As in Perl 5, the parens may be dropped when dereferencing
+a scalar variable.
=item *
@@ -2321,9 +2328,12 @@
to being a no-op in Perl 5). Along the same lines, C<?> imposes
a boolean (C<Bool>) context, and the C<|> unary operator imposes
a function-arguments (C<Capture>) context on its argument.
-Unary sigils impose the container context implied by their sigil.
+Unary sigils are allowed when followed by a C<$> sigil on a scalar variable;
+they impose the container context implied by their sigil.
As with Perl 5, however, C<$$foo[bar]> parses as C<( $($foo) )[bar]>,
-so you need C<$($foo[bar])> to mean the other way.
+so you need C<$($foo[bar])> to mean the other way. In other
+words, sigils are not really parsed as operators, and you must
+use the parenthetical form for anything complicated.
=item *
Modified: docs/Perl6/Spec/S06-routines.pod
===================================================================
--- docs/Perl6/Spec/S06-routines.pod 2009-04-09 23:27:43 UTC (rev 26166)
+++ docs/Perl6/Spec/S06-routines.pod 2009-04-10 00:44:36 UTC (rev 26167)
@@ -13,9 +13,9 @@
Maintainer: Larry Wall <la...@wall.org>
Date: 21 Mar 2003
- Last Modified: 19 Mar 2009
+ Last Modified: 9 Apr 2009
Number: 6
- Version: 107
+ Version: 108
This document summarizes Apocalypse 6, which covers subroutines and the
@@ -1216,7 +1216,7 @@
Otherwise you'd have to say this:
- for @@tmp.zip.@@() -> [$i, $a] { say "$i: $a" }
+ for @@tmp.zip.slice -> [$i, $a] { say "$i: $a" }
In list context the C<@@foo> notation is really a shorthand for C<[;](@@foo)>.
In particular, you can use C<@@foo> to interpolate a multidimensional slice
@@ -1232,13 +1232,13 @@
So
('a'..*; 0..*) ==> *;
- for zip(@@() <== @foo) -> $a, $i, $x { ... }
+ for zip(@@(*) <== @foo) -> $a, $i, $x { ... }
is the same as
'a'..* ==> *;
0..* ==> *;
- for zip(@@ <== @foo) -> $a, $i, $x { ... }
+ for zip(@@(*) <== @foo) -> $a, $i, $x { ... }
which is the same as
@@ -1254,6 +1254,8 @@
C<@()>, C<@@()> defaults to C<@@($/)>, and returns a multidimensional
view of any match that repeatedly applies itself with C<:g> and
the like. In contrast, C<@()> would flatten those into one list.
+It is an error to use C<@(*)> or C<@@(*)> in a context that doesn't
+supply a feed somehow.
=head2 Closure parameters
