C<$a>. If C<$b> is negative, then C<$a % $b> is C<$a> minus the
smallest multiple of C<$b> that is not less than C<$a> (i.e. the
result will be less than or equal to zero). If the operands
-C<$a> and C<$b> are floting point values, only the integer portion
-of C<$a> and C<$b> will be used in the operation.
+C<$a> and C<$b> are floating point values and the absolute value of
+C<$b> (that is C<abs($b)>) is less than C<(UV_MAX + 1)>, only
+the integer portion of C<$a> and C<$b> will be used in the operation
+(Note: here C<UV_MAX> means the maximum of the unsigned integer type).
+If the absolute value of the right operand (C<abs($b)>) is greater than
+or equal to C<(UV_MAX + 1)>, "%" computes the floating-point remainder
+C<$r> in the equation C<($r = $a - $i*$b)> where C<$i> is a certain
+integer that makes C<$r> should have the same sign as the right operand
+C<$b> (B<not> as the left operand C<$a> like C function C<fmod()>)
+and the absolute value less than that of C<$b>.
Note that when C<use integer> is in scope, "%" gives you direct access
to the modulus operator as implemented by your C compiler. This
operator is not as well defined for negative operands, but it will
X<cmp>
Binary "~~" does a smart match between its arguments. Smart matching
-is described in L<perlsyn/"Smart Matching in Detail">.
+is described in L<perlsyn/"Smart matching in detail">.
This operator is only available if you enable the "~~" feature:
see L<feature> for more information.
X<~~>
X<regexp, options> X<regexp> X<regex, options> X<regex>
X</c> X</i> X</m> X</o> X</s> X</x>
-=item /PATTERN/cgimosx
+=item /PATTERN/cgimosxk
Searches a string for a pattern match, and in scalar context returns
true if it succeeds, false if it fails. If no string is specified
Options are:
- c Do not reset search position on a failed match when /g is in effect.
- g Match globally, i.e., find all occurrences.
i Do case-insensitive pattern matching.
m Treat string as multiple lines.
- o Compile pattern only once.
s Treat string as single line.
x Use extended regular expressions.
+ g Match globally, i.e., find all occurrences.
+ c Do not reset search position on a failed match when /g is in effect.
+ o Compile pattern only once.
+ k Keep a copy of the matched string so that ${^MATCH} and friends
+ will be defined.
If "/" is the delimiter then the initial C<m> is optional. With the C<m>
you can use any pair of non-alphanumeric, non-whitespace characters
C<use warnings> pragma and the B<-w> switch (that is, the C<$^W> variable)
produces warnings if the STRING contains the "," or the "#" character.
-=item s/PATTERN/REPLACEMENT/egimosx
+=item s/PATTERN/REPLACEMENT/egimosxk
X<substitute> X<substitution> X<replace> X<regexp, replace>
X<regexp, substitute> X</e> X</g> X</i> X</m> X</o> X</s> X</x>
Options are:
- e Evaluate the right side as an expression.
- g Replace globally, i.e., all occurrences.
i Do case-insensitive pattern matching.
m Treat string as multiple lines.
- o Compile pattern only once.
s Treat string as single line.
x Use extended regular expressions.
+ g Replace globally, i.e., all occurrences.
+ o Compile pattern only once.
+ k Keep a copy of the original string so ${^MATCH} and friends
+ will be defined.
+ e Evaluate the right side as an expression.
+
Any non-alphanumeric, non-whitespace delimiter may replace the
slashes. If single quotes are used, no interpretation is done on the
s/%(.)/$percent{$1}/g; # change percent escapes; no /e
s/%(.)/$percent{$1} || $&/ge; # expr now, so /e
- s/^=(\w+)/&pod($1)/ge; # use function call
+ s/^=(\w+)/pod($1)/ge; # use function call
# expand variables in $_, but dynamics only, using
# symbolic dereferencing
e.g., C<tr[A-Z][a-z]> or C<tr(+\-*/)/ABCD/>.
Note that C<tr> does B<not> do regular expression character classes
-such as C<\d> or C<[:lower:]>. The <tr> operator is not equivalent to
+such as C<\d> or C<[:lower:]>. The C<tr> operator is not equivalent to
the tr(1) utility. If you want to map strings between lower/upper
cases, see L<perlfunc/lc> and L<perlfunc/uc>, and in general consider
using the C<s> operator if you need regular expressions.
=item C<RE> in C<?RE?>, C</RE/>, C<m/RE/>, C<s/RE/foo/>,
-Processing of C<\Q>, C<\U>, C<\u>, C<\L>, C<\l>, and interpolation
-happens (almost) as with C<qq//> constructs.
-
-However combinations of C<\> followed by RE-special chars are not
-substituted but only skipped. The full list of RE-special chars is
-C<\>, C<.>, C<^>, C<$>, C<@>, C<A>, C<G>, C<Z>, C<d>, C<D>, C<w>, C<W>,
-C<s>, C<S>, C<b>, C<B>, C<p>, C<P>, C<X>, C<C>, C<+>, C<*>, C<?>, C<|>,
-C<(>, C<)>, C<->, C<n>, C<r>, C<t>, C<f>, C<e>, C<a>, C<x>, C<c>, C<z>,
-digits (C<0> to C<9>), C<[>, C<{>, C<]>, C<}>, whitespaces (SPACE, TAB,
-LF, CR, FF, and VT in addition), and C<#>.
+Processing of C<\Q>, C<\U>, C<\u>, C<\L>, C<\l>, C<\E>,
+and interpolation happens (almost) as with C<qq//> constructs.
+
+However any other combinations of C<\> followed by a character
+are not substituted but only skipped, in order to parse them
+as regular expressions at the following step.
As C<\c> is skipped at this step, C<@> of C<\c@> in RE is possibly
treated as an array symbol (for example C<@foo>),
even though the same text in C<qq//> gives interpolation of C<\c@>.
-Note that C<\N{name}> is interpolated at this step.
Moreover, inside C<(?{BLOCK})>, C<(?# comment )>, and
a C<#>-comment in a C<//x>-regular expression, no processing is
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