diff options
Diffstat (limited to 'Master/tlpkg/tlperl/lib/fields.pm')
| -rw-r--r-- | Master/tlpkg/tlperl/lib/fields.pm | 69 |
1 files changed, 30 insertions, 39 deletions
diff --git a/Master/tlpkg/tlperl/lib/fields.pm b/Master/tlpkg/tlperl/lib/fields.pm index fd59b6a465e..ad1a5cfa412 100644 --- a/Master/tlpkg/tlperl/lib/fields.pm +++ b/Master/tlpkg/tlperl/lib/fields.pm @@ -11,7 +11,7 @@ unless( eval q{require warnings::register; warnings::register->import; 1} ) { } use vars qw(%attr $VERSION); -$VERSION = '2.16'; +$VERSION = '2.17'; # constant.pm is slow sub PUBLIC () { 2**0 } @@ -200,9 +200,13 @@ fields - compile-time class fields my $var = Foo->new; $var->{foo} = 42; - # this will generate an error + # this will generate a run-time error $var->{zap} = 42; + # this will generate a compile-time error + my Foo $foo = Foo->new; + $foo->{zap} = 24; + # subclassing { package Bar; @@ -220,38 +224,34 @@ fields - compile-time class fields =head1 DESCRIPTION -The C<fields> pragma enables compile-time verified class fields. +The C<fields> pragma enables compile-time and run-time verified class +fields. NOTE: The current implementation keeps the declared fields in the %FIELDS hash of the calling package, but this may change in future versions. Do B<not> update the %FIELDS hash directly, because it must be created at compile-time for it to be fully useful, as is done by this pragma. -B<Only valid for perl before 5.9.0:> - -If a typed lexical variable holding a reference is used to access a +If a typed lexical variable (C<my Class +$var>) holding a reference is used to access a hash element and a package with the same name as the type has -declared class fields using this pragma, then the operation is -turned into an array access at compile time. - +declared class fields using this pragma, then the hash key is +verified at compile time. If the variables are not typed, access is +only checked at run time. The related C<base> pragma will combine fields from base classes and any fields declared using the C<fields> pragma. This enables field -inheritance to work properly. - -Field names that start with an underscore character are made private to -the class and are not visible to subclasses. Inherited fields can be -overridden but will generate a warning if used together with the C<-w> -switch. - -B<Only valid for perls before 5.9.0:> +inheritance to work properly. Inherited fields can be overridden but +will generate a warning if warnings are enabled. -The effect of all this is that you can have objects with named -fields which are as compact and as fast arrays to access. This only -works as long as the objects are accessed through properly typed -variables. If the objects are not typed, access is only checked at -run time. +B<Only valid for Perl 5.8.x and earlier:> Field names that start with an +underscore character are made private to the class and are not visible +to subclasses. +Also, B<in Perl 5.8.x and earlier>, this pragma uses pseudo-hashes, the +effect being that you can have objects with named fields which are as +compact and as fast arrays to access, as long as the objects are +accessed through properly typed variables. The following functions are supported: @@ -259,15 +259,8 @@ The following functions are supported: =item new -B< perl before 5.9.0: > fields::new() creates and blesses a -pseudo-hash comprised of the fields declared using the C<fields> -pragma into the specified class. - -B< perl 5.9.0 and higher: > fields::new() creates and blesses a -restricted-hash comprised of the fields declared using the C<fields> -pragma into the specified class. - -This function is usable with or without pseudo-hashes. It is the +fields::new() creates and blesses a hash comprised of the fields declared +using the C<fields> pragma into the specified class. It is the recommended way to construct a fields-based object. This makes it possible to write a constructor like this: @@ -285,7 +278,11 @@ This makes it possible to write a constructor like this: =item phash -B< before perl 5.9.0: > +B<This function only works in Perl 5.8.x and earlier.> Pseudo-hashes +were removed from Perl as of 5.10. Consider using restricted hashes or +fields::new() instead (which itself uses restricted hashes under 5.10+). +See L<Hash::Util>. Using fields::phash() under 5.10 or higher will +cause an error. fields::phash() can be used to create and initialize a plain (unblessed) pseudo-hash. This function should always be used instead of creating @@ -312,16 +309,10 @@ be used to construct the pseudo hash. Examples: my $pseudohash = fields::phash(%args); -B< perl 5.9.0 and higher: > - -Pseudo-hashes have been removed from Perl as of 5.10. Consider using -restricted hashes or fields::new() instead. Using fields::phash() -will cause an error. - =back =head1 SEE ALSO -L<base> +L<base>, L<Hash::Util> =cut |