Author: larry
Date: Wed Jul 19 11:21:01 2006
New Revision: 10304
Modified:
doc/trunk/design/syn/S02.pod
doc/trunk/design/syn/S03.pod
doc/trunk/design/syn/S04.pod
Log:
Generalize long dot to "unspace" to futureproof against grammar mods.
(And also to allow suppression of any curly-at-the-end-of-line misparse. :)
Modified: doc/trunk/design/syn/S02.pod
==============================================================================
--- doc/trunk/design/syn/S02.pod (original)
+++ doc/trunk/design/syn/S02.pod Wed Jul 19 11:21:01 2006
@@ -12,9 +12,9 @@
Maintainer: Larry Wall <[EMAIL PROTECTED]>
Date: 10 Aug 2004
- Last Modified: 18 July 2006
+ Last Modified: 19 July 2006
Number: 2
- Version: 51
+ Version: 52
This document summarizes Apocalypse 2, which covers small-scale
lexical items and typological issues. (These Synopses also contain
@@ -173,6 +173,17 @@
=item *
+In fact, any whitespace (including comments) may be hidden by prefixing
+it with C<\>. It does not have to end with a dot. It's just that
+the normal use of a you-don't-see-this-space is typically to put
+a dotted postfix on the next line. But it also lets you continue
+the line in any situation where a newline might confuse the parser,
+regardless of the currently installed parser. (Unless, of course,
+you override the unspace rule itself...) Although we say that the
+unspace hides the whitespace from the parser, line numbers are still counted.
+
+=item *
+
In general, whitespace is optional in Perl 6 except where it is needed
to separate constructs that would be misconstrued as a single token or
other syntactic unit. (In other words, Perl 6 follows the standard
@@ -210,9 +221,13 @@
.++
$x\ # comment
- # more comment
+ # inside long dot
.++
+ $x\ # comment
+ # inside "unspace"
+ ++ # (but long dot may be preferred...)
+
$x\#『 comment
more comment
』.++
@@ -266,7 +281,7 @@
postfix dot will be taken to be the start of some kind of method call
syntax, whether long-dotty or not. (The C<.123> form with a leading
dot is still allowed however when a term is expected, and is equivalent
-to C<0.123>.)
+to C<0.123> rather than C<$_.123>.)
=back
Modified: doc/trunk/design/syn/S03.pod
==============================================================================
--- doc/trunk/design/syn/S03.pod (original)
+++ doc/trunk/design/syn/S03.pod Wed Jul 19 11:21:01 2006
@@ -12,9 +12,9 @@
Maintainer: Larry Wall <[EMAIL PROTECTED]>
Date: 8 Mar 2004
- Last Modified: 18 Jul 2006
+ Last Modified: 19 Jul 2006
Number: 3
- Version: 50
+ Version: 51
=head1 Changes to existing operators
@@ -95,10 +95,14 @@
=item * The scalar comma C<,> now constructs a C<List> object from its
operands. You have to use a C<[-1]> subscript to get the last one.
-=item * The backslash operator captures its arguments, and returns an
+=item * The unary backslash operator captures its arguments, and returns an
object representing those arguments. You can I<dereference> this object
in several ways to retrieve different parts of the arguments; see the
-definition of C<Capture> in S02 for details.
+definition of C<Capture> in S02 for details. (No whitespace is allowed
+after the backslash because that would instead start an "unspace", that is,
+an escaped sequence of whitespace or comments. See S02 for details.
+However, oddly enough, because of that unspace rule, saying C<\\ $foo>
+turns out to be equivalent to C<\$foo>.)
=item * The old scalar C<..> flipflop operator is now done with
C<ff> operator. (C<..> now always produces a C<Range> object
@@ -329,10 +333,11 @@
of postfix operators.
=item * A list operator's arguments are also terminated by a closure
-that is not followed by a comma or colon. (And a semicolon is implied if
-the closure is the final thing on a line.) This final closure may be
-followed by a postfix, in which case the postfix is applied to the result
-of the entire list operator.
+that is not followed by a comma or colon. (And a semicolon is implied
+if the closure is the final thing on a line. Use an "unspace" to
+suppress that.) This final closure may be followed by a postfix,
+in which case the postfix is applied to the result of the entire
+list operator.
=item * A function predeclared as 0-ary is never considered list
operator, though it allows an optional set of empty parentheses.
Modified: doc/trunk/design/syn/S04.pod
==============================================================================
--- doc/trunk/design/syn/S04.pod (original)
+++ doc/trunk/design/syn/S04.pod Wed Jul 19 11:21:01 2006
@@ -12,9 +12,9 @@
Maintainer: Larry Wall <[EMAIL PROTECTED]>
Date: 19 Aug 2004
- Last Modified: 16 July 2006
+ Last Modified: 18 July 2006
Number: 4
- Version: 27
+ Version: 28
This document summarizes Apocalypse 4, which covers the block and
statement syntax of Perl.
@@ -747,8 +747,10 @@
to the precedence of semicolon whether or not you put a semicolon
after it. (In the absence of an explicit semicolon, the current
statement may continue on a subsequent line, but only with valid
-statement continuators such as C<else>. A modifier on a C<loop>
-statement must continue on the same line, however.)
+statement continuators such as C<else> that cannot be confused with
+the beginning of a new statement. Anything else, such as a statement
+modifier (on, say, a C<loop> statement) must continue on the same line,
+unless the newline be escaped using the "unspace" construct--see S02.)
Final blocks on statement-level constructs always imply semicolon
precedence afterwards regardless of the position of the closing curly.
@@ -783,6 +785,14 @@
since C<< prefix:<if> >> would hide C<< statement_modifier:<if> >>.
+Built-in statement-level keywords require whitespace between the
+keyword and the first argument, as well as before any terminating loop.
+In particular, a syntax error will be reported for C-isms such as these:
+
+ if(...) {...}
+ while(...) {...}
+ for(...) {...}
+
=head1 Definition of Success
Hypothetical variables are somewhat transactional--they keep their
