Author: autrijus
Date: Thu Apr 20 23:49:15 2006
New Revision: 8893
Modified:
doc/trunk/design/syn/S05.pod
Log:
Stylistic cleanup of S05; no functional changes.
* s/TimToady/Larry Wall/
* Consistently change "foo" to C<foo> or I<foo> to be consistent
with context.
* Fixed the "state $x ||= /.../" example, which will cause rematch
on matchfail. "state $x //= /.../" would be the correct form.
* Clarified that only Int or Range objects can sensibly be used
as quantifier range; matching something "3.5+6i" times wouldn't
quite make sense.
Modified: doc/trunk/design/syn/S05.pod
==============================================================================
--- doc/trunk/design/syn/S05.pod (original)
+++ doc/trunk/design/syn/S05.pod Thu Apr 20 23:49:15 2006
@@ -11,16 +11,17 @@
=head1 VERSION
- Maintainer: Patrick Michaud <[EMAIL PROTECTED]> (& TimToady)
+ Maintainer: Patrick Michaud <[EMAIL PROTECTED]> and
+ Larry Wall <[EMAIL PROTECTED]>
Date: 24 Jun 2002
Last Modified: 20 Apr 2006
Number: 5
- Version: 17
+ Version: 18
This document summarizes Apocalypse 5, which is about the new regex
-syntax. We now try to call them "regex" because they haven't been
+syntax. We now try to call them I<regex> because they haven't been
regular expressions for a long time. When referring to their use in
-a grammar, the term "rule" is preferred.
+a grammar, the term I<rule> is preferred.
=head1 New match state and capture variables
@@ -126,7 +127,7 @@
Since this is implicitly anchored to the position, it's suitable for
building parsers and lexers. The pattern you supply to a Perl macro's
-"is parsed" trait has an implicit C<:p> modifier.
+C<is parsed> trait has an implicit C<:p> modifier.
Note that
@@ -266,7 +267,7 @@
=item *
-The new C<:rw> modifier causes this regex to "claim" the current
+The new C<:rw> modifier causes this regex to I<claim> the current
string for modification rather than assuming copy-on-write semantics.
All the bindings in C<$/> become lvalues into the string, such
that if you modify, say, C<$1>, the original string is modified in
@@ -394,8 +395,8 @@
=item *
-C<.> matches an "anything", while C<\N> matches an "anything except
-newline". (The C</s> modifier is gone.) In particular, C<\N> matches
+C<.> matches an I<anything>, while C<\N> matches an I<anything except
+newline>. (The C</s> modifier is gone.) In particular, C<\N> matches
neither carriage return nor line feed.
=item *
@@ -451,7 +452,7 @@
The repetition specifier is now C<**{...}> for maximal matching,
with a corresponding C<**{...}?> for minimal matching. Space is
allowed on either side of the asterisks. The curlies are taken to
-be a closure returning a number or a range.
+be a closure returning an Int or a Range object.
/ value was (\d ** {1..6}?) with ([\w]**{$m..$n}) /
@@ -459,7 +460,7 @@
/ [foo]**{1,3} /
-(At least, it fails in the absence of "C<use rx :listquantifier>",
+(At least, it fails in the absence of C<use rx :listquantifier>,
which is likely to be unimplemented in Perl 6.0.0 anyway).
The optimizer will likely optimize away things like C<**{1...}>
@@ -471,7 +472,7 @@
=item *
-C<< <...> >> are now extensible metasyntax delimiters or "assertions"
+C<< <...> >> are now extensible metasyntax delimiters or I<assertions>
(i.e. they replace Perl 5's crufty C<(?...)> syntax).
=back
@@ -486,7 +487,7 @@
=item *
-Instead they're passed "raw" to the regex engine, which can then decide
+Instead they're passed I<raw> to the regex engine, which can then decide
how to handle them (more on that below).
=item *
@@ -520,7 +521,7 @@
As with a scalar variable, each element is matched as a literal
unless it happens to be a Regex object, in which case it is matched
as a subrule. As with scalar subrules, a tainted subrule always fails.
-All values pay attention to the current C<:ignorecase> setting
+All values pay attention to the current C<:ignorecase> setting.
=item *
@@ -539,7 +540,7 @@
If the value is a string, it is matched literally, starting after where
the key left off matching. As a natural consequence, if the value is
-"", nothing special happens except that the key match succeeds.
+C<"">, nothing special happens except that the key match succeeds.
=item *
@@ -669,7 +670,7 @@
internally that turns into a hash lookup.)
As with bare hash, the longest key matches according to the venerable
-"longest token rule", but in addition, you may combine multiple hashes
+I<longest token rule>, but in addition, you may combine multiple hashes
under the same longest-token consideration like this:
<%statement|%prefix|%term>
@@ -761,10 +762,10 @@
/ <after foo> \d+ <before bar> /
-except that the scan for "foo" can be done in the forward direction,
+except that the scan for "C<foo>" can be done in the forward direction,
while a lookbehind assertion would presumably scan for C<\d+> and then
match "C<foo>" backwards. The use of C<< <(...)> >> affects only the
-meaning of the "result object" and the positions of the beginning and
+meaning of the I<result object> and the positions of the beginning and
ending of the match. That is, after the match above, C<$()> contains
only the digits matched, and C<.pos> is pointing to after the digits.
Other captures (named or numbered) are unaffected and may be accessed
@@ -966,7 +967,7 @@
=item *
The name of the constructor was changed from C<qr> because it's no
-longer an interpolating quote-like operator. C<rx> is short for "regex",
+longer an interpolating quote-like operator. C<rx> is short for I<regex>,
(not to be confused with regular expressions).
=item *
@@ -1062,12 +1063,12 @@
=item *
-The Perl 5 C<?...?> syntax ("match once") was rarely used and can be
+The Perl 5 C<?...?> syntax (I<match once>) was rarely used and can be
now emulated more cleanly with a state variable:
- (state $x) ||= / pattern /; # only matches first time
+ (state $x) //= / pattern /; # only matches first time
-To reset the pattern, simply set C<$x = 0>.
+To reset the pattern, simply say C<undefine $x>.
=back
@@ -1154,7 +1155,7 @@
m:w/ sub <subname>? <block> /
(i.e. using a reserved word as a subroutine name is instantly fatal
-to the "surrounding" match as well)
+to the I<surrounding> match as well)
=item *
@@ -1287,7 +1288,7 @@
=item *
-A match always returns a "match object", which is also available
+A match always returns a Match object, which is also available
as C<$/>, which is an environmental lexical declared in the outer
subroutine that is calling the regex. (A closure lexically embedded
in a regex does not redeclare C<$/>, so C<$/> always refers to the
@@ -1296,7 +1297,7 @@
=item *
Notionally, a match object contains (among other things) a boolean
-success value, a scalar "result object", an array of ordered submatch
+success value, a scalar I<result object>, an array of ordered submatch
objects, and a hash of named submatch objects. To provide convenient
access to these various values, the match object evaluates differently
in different contexts:
@@ -1386,7 +1387,7 @@
$mystring = "{ m:w/ (\S+) => (\S+)/[0] }";
-To get all the captures into a string, use a "zen" slice:
+To get all the captures into a string, use a I<zen> slice:
$mystring = "{ m:w/ (\S+) => (\S+)/[] }";
@@ -1879,7 +1880,7 @@
=item *
However, if a subrule is explicitly renamed (or aliased -- see L<Aliasing>),
-then only the "final" name counts when deciding whether it is or isn't
+then only the I<final> name counts when deciding whether it is or isn't
repeated. For example:
if m:w/ mv <file> $<dir>:=<file> / {
@@ -2092,7 +2093,7 @@
=item *
-This "follow-on" behavior is particularly useful for reinstituting
+This I<follow-on> behavior is particularly useful for reinstituting
Perl5 semantics for consecutive subpattern numbering in alternations:
$tune_up = rx/ (don't) (ray) (me) (for) (solar tea), (d'oh!)
@@ -2426,7 +2427,7 @@
m/ mv @<files>:=<ident>+ $<dir>:=<ident> /
-the name of an ordinary variable can be used as an "external alias", like so:
+the name of an ordinary variable can be used as an I<external> alias, like so:
m/ mv @files:=<ident>+ $dir:=<ident> /
@@ -2539,7 +2540,7 @@
If subs are the model for rules, then modules/classes are the obvious
model for aggregating them. Such collections of rules are generally
-known as "grammars".
+known as I<grammars>.
=item *
