=item *
-There's no switch statement. (But it's easy to build one on the fly,
-see L<perlsyn/"Basic BLOCKs and Switch Statements">)
+The switch statement is called C<given/when> and only available in
+perl 5.10 or newer. See L<perlsyn/"Switch statements">.
=item *
whether this should be classed as a bug or not.
(The older package delimiter, ' ,is used here)
- $x = 10 ;
- print "x=${'x}\n" ;
+ $x = 10;
+ print "x=${'x}\n";
# perl4 prints: x=10
# perl5 prints: Can't find string terminator "'" anywhere before EOF
You can avoid this problem, and remain compatible with perl4, if you
always explicitly include the package name:
- $x = 10 ;
- print "x=${main'x}\n" ;
+ $x = 10;
+ print "x=${main'x}\n";
Also see precedence traps, for parsing C<$:>.
Double darn.
$a = ("foo bar");
- $b = q baz ;
+ $b = q baz;
print "a is $a, b is $b\n";
# perl4 prints: a is foo bar, b is baz
# perl4 prints: {a}
# perl5 prints: 2
-=item * Perl guesses on C<map>, C<grep> followed by C<{> whether C<{> starts BLOCK or hash ref
+=item * Perl guesses on C<map>, C<grep> followed by C<{> if it starts BLOCK or hash ref
When perl sees C<map {> (or C<grep {>), it has to guess whether the C<{>
starts a BLOCK or a hash reference. If it guesses wrong, it will report
use Math::BigInt;
-=item * Assignment of return values from numeric equality tests doesn't works
+=item * Assignment of return values from numeric equality tests doesn't work
Assignment of return values from numeric equality tests
does not work in perl5 when the test evaluates to false (0).
$opt = 'r';
$_ = 'bar';
s/^([^$grpc]*$grpc[$opt]?)/foo/;
- print ;
+ print;
# perl4 prints: foo
# perl5 prints: foobar
=over 5
-=item * Barewords that used to look like strings look like subroutine calls if a subroutine by that name is defined
+=item * Barewords that used to look like strings look like subroutine calls
Barewords that used to look like strings to Perl will now look like subroutine
calls if a subroutine by that name is defined before the compiler sees them.
the file.
open(TEST,">>seek.test");
- $start = tell TEST ;
+ $start = tell TEST;
foreach(1 .. 9){
print TEST "$_ ";
}
- $end = tell TEST ;
+ $end = tell TEST;
seek(TEST,$start,0);
print TEST "18 characters here";
Note: perl5 DOES NOT error on the terminating @ in $bar
-=item * Arbitrary expressions are evaluated inside braces that occur within double quotes
+=item * Arbitrary expressions are evaluated inside braces within double quotes
Perl now sometimes evaluates arbitrary expressions inside braces that occur
within double quotes (usually when the opening brace is preceded by C<$>
# perl4 prints: this is XXXx (XXX is the current pid)
# perl5 prints: this is a reference
-=item * Creation of hashes on the fly with C<eval "EXPR"> requires protection of C<$>'s or both curlies
+=item * Creation of hashes on the fly with C<eval "EXPR"> requires protection
Creation of hashes on the fly with C<eval "EXPR"> now requires either both
C<$>'s to be protected in the specification of the hash name, or both curlies
=over 5
-=item * Perl5 must have been linked with the same dbm/ndbm as the default for C<dbmopen()> to function properly without C<tie>'ing
+=item * Perl5 must have been linked with same dbm/ndbm as the default for C<dbmopen()>
Existing dbm databases created under perl4 (or any other dbm/ndbm tool)
may cause the same script, run under perl5, to fail. The build of perl5
# perl5 prints: ok (IFF linked with -ldbm or -lndbm)
-=item * DBM exceeding the limit on the key/value size will cause perl5 to exit immediately
+=item * DBM exceeding limit on the key/value size will cause perl5 to exit immediately
Existing dbm databases created under perl4 (or any other dbm/ndbm tool)
may cause the same script, run under perl5, to fail. The error generated
https://perl5.git.perl.org / perl5.git / blobdiff