Author: lwall
Date: 2010-04-10 20:12:11 +0200 (Sat, 10 Apr 2010)
New Revision: 30359
Modified:
docs/Perl6/Spec/S02-bits.pod
Log:
[S02] explicate (non)-relationship of interpolation and whitespace/unspace
Modified: docs/Perl6/Spec/S02-bits.pod
===================================================================
--- docs/Perl6/Spec/S02-bits.pod 2010-04-10 16:29:54 UTC (rev 30358)
+++ docs/Perl6/Spec/S02-bits.pod 2010-04-10 18:12:11 UTC (rev 30359)
@@ -13,8 +13,8 @@
Created: 10 Aug 2004
- Last Modified: 7 Apr 2010
- Version: 212
+ Last Modified: 10 Apr 2010
+ Version: 213
This document summarizes Apocalypse 2, which covers small-scale
lexical items and typological issues. (These Synopses also contain
@@ -3148,6 +3148,10 @@
notations work in normal Perl code. They work only in interpolations
and regexes and the like.
+Note that the inside of the brackets is not an expression, and you
+may not interpolate there, since that would be a double interpolation.
+Use curlies to interpolate the values of expressions.
+
The old C<\123> form is now illegal, as is the C<\0123> form.
Only C<\0> remains, and then only if the next character is not in
the range C<'0'..'7'>. Octal characters must use C<\o> notation.
@@ -3602,7 +3606,18 @@
"Val = { $a.ord.fmt('%x') }\n"
+However, no interpolated postfix may start with a backslash, so any
+backslash or unspace is not recognized, but instead will be assumed
+to be part of the string outside of the interpolation, and subject
+to the normal backslashing rules of that quote context:
+ my $a = 42;
+ "Val = $a\[junk\]"; # Val = 42[junk]
+ "Val = $a\[junk]"; # Val = 42[junk]
+ "Val = $a\ [junk]"; # Val = 42 [junk]
+ "Val = $a\.[junk]"; # Val = 42.[junk]
+
+
=item *
In order to interpolate an entire array, it's necessary now to subscript
@@ -3664,13 +3679,19 @@
=item *
Multiple dereferencers may be stacked as long as each one ends in
-some kind of bracket:
+some kind of bracket or is a bare method:
- print "The attribute is @baz[3](1,2,3){$xyz}<blurfl>.attr().\n"
+ print "The attribute is @baz[3](1, 2, 3).gethash.{$xyz}<blurfl>.attr().\n"
Note that the final period above is not taken as part of the expression since
-it doesn't introduce a bracketed dereferencer.
+it doesn't introduce a bracketed dereferencer. The parens are not required
+on the C<.gethash>, but they are required on the C<.attr()>, since that
+terminates the entire interpolation.
+In no case may any of the top-level components be separated by
+whitespace or unspace. (These are allowed, though, inside any
+bracketing constructs, such as in the C<(1, 2, 3)> above.)
+
=item *
A bare closure also interpolates in double-quotish context. It may
@@ -3678,11 +3699,14 @@
inside the closure. The expression inside is evaluated in string item
context. You can force list context on the expression using
the C<list> operator if necessary. A closure in a string establishes
-its own lexical scope.
+its own lexical scope. (Expressions that sneak in without curlies,
+such as C<$(...)>, do not establish their own lexical scope, but use
+the outer scope, and may even declare variables in the outer scope, since
+all the code inside (that isn't in an eval) is seen at compile time.)
The following means the same as the previous example.
- print "The attribute is { @baz[3](1,2,3){$xyz}<blurfl>.attr }.\n"
+ print "The attribute is { @baz[3](1,2,3).gethash.{$xyz}<blurfl>.attr }.\n"
The final parens are unnecessary since we're providing "real" code in
the curlies. If you need to have double quotes that don't interpolate
