package Sub::Prototype::Util;
+use 5.006;
+
use strict;
use warnings;
=head1 VERSION
-Version 0.05
+Version 0.09
=cut
use vars qw/$VERSION/;
-$VERSION = '0.05';
+$VERSION = '0.09';
=head1 SYNOPSIS
- use Sub::Prototype::Util qw/flatten recall/;
+ use Sub::Prototype::Util qw/flatten wrap recall/;
my @a = qw/a b c/;
my @args = ( \@a, 1, { d => 2 }, undef, 3 );
my @flat = flatten '\@$;$', @args; # ('a', 'b', 'c', 1, { d => 2 })
recall 'CORE::push', @args; # @a contains 'a', 'b', 'c', 1, { d => 2 }, undef, 3
+ my $splice = wrap 'CORE::splice';
+ my @b = $splice->(\@a, 4, 2); # @a is now ('a', 'b', 'c', 1, 3) and @b is ({ d => 2 }, undef)
=head1 DESCRIPTION
-Prototypes are evil, but sometimes you just have to bear with them, especially when messing with core functions. This module provides several utilities aimed at facilitating "overloading" of prototyped functions.
+Prototypes are evil, but sometimes you just have to bear with them, especially when messing with core functions.
+This module provides several utilities aimed at facilitating "overloading" of prototyped functions.
They all handle C<5.10>'s C<_> prototype.
=cut
my %sigils = qw/SCALAR $ ARRAY @ HASH % GLOB * CODE &/;
+my %reftypes = reverse %sigils;
sub _check_ref {
my ($a, $p) = @_;
return $r;
}
+sub _clean_msg {
+ my ($msg) = @_;
+ $msg =~ s/(?:\s+called)?\s+at\s+.*$//s;
+ return $msg;
+}
+
=head2 C<flatten $proto, @args>
-Flattens the array C<@args> according to the prototype C<$proto>. When C<@args> is what C<@_> is after calling a subroutine with prototype C<$proto>, C<flatten> returns the list of what C<@_> would have been if there were no prototype.
+Flattens the array C<@args> according to the prototype C<$proto>.
+When C<@args> is what C<@_> is after calling a subroutine with prototype C<$proto>, C<flatten> returns the list of what C<@_> would have been if there were no prototype.
+It croaks if the arguments can't possibly match the required prototype, e.g. when a reference type is wrong or when not enough elements were provided.
=cut
sub flatten {
my $proto = shift;
return @_ unless defined $proto;
- my @args;
+ my @args;
while ($proto =~ /(\\?)(\[[^\]]+\]|[^\];])/g) {
my $p = $2;
if ($1) {
my $a = shift;
my $r = _check_ref $a, $p;
- my %deref = (
- SCALAR => sub { push @args, $$a },
- ARRAY => sub { push @args, @$a },
- HASH => sub { push @args, %$a },
- GLOB => sub { push @args, *$a },
- CODE => sub { push @args, &$a }
- );
- $deref{$r}->();
+ push @args, $r eq 'SCALAR'
+ ? $$a
+ : ($r eq 'ARRAY'
+ ? @$a
+ : ($r eq 'HASH'
+ ? %$a
+ : ($r eq 'GLOB'
+ ? *$a
+ : &$a # _check_ref ensures this must be a code ref
+ )
+ )
+ );
} elsif ($p =~ /[\@\%]/) {
push @args, @_;
last;
- } elsif ($p eq '_' && @_ == 0) {
- push @args, $_;
} else {
+ croak 'Not enough arguments to match this prototype' unless @_;
push @args, shift;
}
}
return @args;
}
-=head2 C<recall $name, @args>
+=head2 C<wrap $name, %opts>
-Calls the function C<$name> with the prototyped argument list C<@args>. That is, C<@args> should be what C<@_> is when you define a subroutine with the same prototype as C<$name>. For example,
+Generates a wrapper that calls the function C<$name> with a prototyped argument list.
+That is, the wrapper's arguments should be what C<@_> is when you define a subroutine with the same prototype as C<$name>.
- my $a = [ ];
- recall 'CORE::push', $a, 1, 2, 3;
+ my $a = [ 0 .. 2 ];
+ my $push = wrap 'CORE::push';
+ $push->($a, 3, 4); # returns 3 + 2 = 5 and $a now contains 0 .. 4
+
+You can force the use of a specific prototype.
+In this case, C<$name> must be a hash reference that holds exactly one key / value pair, the key being the function name and the value the prototpye that should be used to call it.
+
+ my $push = wrap { 'CORE::push' => '\@$' }; # only pushes 1 arg
+
+Others arguments are seen as key / value pairs that are meant to tune the code generated by L</wrap>.
+Valid keys are :
+
+=over 4
+
+=item C<< ref => $func >>
+
+Specifies the function used in the generated code to test the reference type of scalars.
+Defaults to C<'ref'>.
+You may also want to use L<Scalar::Util/reftype>.
+
+=item C<< wrong_ref => $code >>
-will call C<push @$a, 1, 2, 3> and so fill the arrayref C<$a> with C<1, 2, 3>. This is especially needed for core functions because you can't C<goto> into them.
+The code executed when a reference of incorrect type is encountered.
+The result of this snippet is also the result of the generated code, hence it defaults to C<'undef'>.
+It's a good place to C<croak> or C<die> too.
-You can also force the use of a specific prototype. In this case, C<$name> must be a hash reference that holds exactly one key/value pair, the key being the function name and the value the prototpye that should be used to call it.
+=item C<< sub => $bool >>
- recall { 'CORE::push' => '\@$' }, $a, 1, 2, 3; # will only push 1
+Encloses the code into a C<sub { }> block.
+Default is true.
-This allows you to recall into C<CORE::grep> and C<CORE::map> by using the C<\&@> prototype :
+=item C<< compile => $bool >>
- sub mygrep (&@) { recall { 'CORE::grep' => '\&@' }, @_ } # the prototypes are intentionally different
+Makes L</wrap> compile the code generated and return the resulting code reference.
+Be careful that in this case C<ref> must be a fully qualified function name.
+Defaults to true, but turned off when C<sub> is false.
+
+=back
+
+For example, this allows you to recall into C<CORE::grep> and C<CORE::map> by using the C<\&@> prototype :
+
+ my $grep = wrap { 'CORE::grep' => '\&@' };
+ sub mygrep (&@) { $grep->(@_) } # the prototypes are intentionally different
=cut
-sub recall {
- my $name = shift;
+sub _wrap {
+ my ($name, $proto, $i, $args, $cr, $opts) = @_;
+ while ($proto =~ s/(\\?)(\[[^\]]+\]|[^\];])//) {
+ my ($ref, $p) = ($1, $2);
+ $p = $1 if $p =~ /^\[([^\]]+)\]/;
+ my $cur = '$_[' . $i . ']';
+ if ($ref) {
+ if (length $p > 1) {
+ return 'my $r = ' . $opts->{ref} . '(' . $cur . '); '
+ . join ' els',
+ map( {
+ "if (\$r eq '" . $reftypes{$_} ."') { "
+ . _wrap($name, $proto, ($i + 1),
+ $args . $_ . '{' . $cur . '}, ',
+ $cr, $opts)
+ . ' }'
+ } split //, $p),
+ 'e { ' . $opts->{wrong_ref} . ' }'
+ } else {
+ $args .= $p . '{' . $cur . '}, ';
+ }
+ } elsif ($p =~ /[\@\%]/) {
+ $args .= '@_[' . $i . '..$#_]';
+ } elsif ($p =~ /\&/) {
+ my %h = do { my $c; map { $_ => $c++ } @$cr };
+ my $j;
+ if (not exists $h{$i}) {
+ push @$cr, $i;
+ $j = $#{$cr};
+ } else {
+ $j = int $h{$i};
+ }
+ $args .= 'sub{&{$c[' . $j . ']}}, ';
+ } elsif ($p eq '_') {
+ $args .= '((@_ > ' . $i . ') ? ' . $cur . ' : $_), ';
+ } else {
+ $args .= $cur . ', ';
+ }
+ ++$i;
+ }
+ $args =~ s/,\s*$//;
+ return $name . '(' . $args . ')';
+}
+
+sub _check_name {
+ my $name = $_[0];
croak 'No subroutine specified' unless $name;
my $proto;
my $r = ref $name;
- if ($r eq 'HASH') {
+ if (!$r) {
+ $proto = prototype $name;
+ } elsif ($r eq 'HASH') {
croak 'Forced prototype hash reference must contain exactly one key/value pair' unless keys %$name == 1;
($name, $proto) = %$name;
- } elsif (length $r) {
+ } else {
croak 'Unhandled ' . $r . ' reference as first argument';
}
$name =~ s/^\s+//;
$name =~ s/[\s\$\@\%\*\&;].*//;
- $proto = prototype $name unless $proto;
- my $call = $name . '(';
+ return $name, $proto;
+}
+
+sub wrap {
+ my ($name, $proto) = _check_name shift;
+ croak 'Optional arguments must be passed as key => value pairs' if @_ % 2;
+ my %opts = @_;
+ $opts{ref} ||= 'ref';
+ $opts{sub} = 1 if not defined $opts{sub};
+ $opts{compile} = 1 if not defined $opts{compile} and $opts{sub};
+ $opts{wrong_ref} = 'undef' if not defined $opts{wrong_ref};
my @cr;
+ my $call;
if (defined $proto) {
- my $i = 0;
- while ($proto =~ /(\\?)(\[[^\]]+\]|[^\];])/g) {
- my $p = $2;
- if ($1) {
- my $r = _check_ref $_[$i], $p;
- $call .= $sigils{$r} . '{$_[' . $i . ']},';
- } elsif ($p =~ /[\@\%]/) {
- $call .= '@_[' . $i . '..' . (@_ - 1) . ']';
- last;
- } elsif ($p =~ /\&/) {
- push @cr, $_[$i];
- $call .= 'sub{&{$cr[' . $#cr . ']}},';
- } elsif ($p eq '_' && $i >= @_) {
- $call .= '$_,';
- } else {
- $call .= '$_[' . $i . '],';
- }
- ++$i;
- }
- $call =~ s/,$//;
+ $call = _wrap $name, $proto, 0, '', \@cr, \%opts;
} else {
- $call .= join ',', map '$_[' . $_ . ']', 0 .. @_ - 1;
+ $call = _wrap $name, '', 0, '@_';
+ }
+ if (@cr) {
+ $call = 'my @c; '
+ . join('', map { 'push @c, $_[' . $_ . ']; ' } @cr)
+ . $call
+ }
+ $call = '{ ' . $call . ' }';
+ $call = 'sub ' . $call if $opts{sub};
+ if ($opts{compile}) {
+ $call = eval $call;
+ croak _clean_msg $@ if $@;
}
- $call .= ');';
- my @ret = eval $call;
- croak $@ if $@;
- return @ret;
+ return $call;
+}
+
+=head2 C<recall $name, @args>
+
+Calls the function C<$name> with the prototyped argument list C<@args>.
+That is, C<@args> should be what C<@_> is when you call a subroutine with C<$name> as prototype.
+You can still force the prototype by passing C<< { $name => $proto } >> as the first argument.
+
+ my $a = [ ];
+ recall { 'CORE::push' => '\@$' }, $a, 1, 2, 3; # $a just contains 1
+
+It's implemented in terms of L</wrap>, and hence calls C<eval> at each run.
+If you plan to recall several times, consider using L</wrap> instead.
+
+=cut
+
+sub recall {
+ my $wrap = eval { wrap shift };
+ croak _clean_msg $@ if $@;
+ return $wrap->(@_);
}
=head1 EXPORT
-The functions L</flatten> and L</recall> are only exported on request, either by providing their name or by the C<':funcs'> and C<':all'> tags.
+The functions L</flatten>, L</wrap> and L</recall> are only exported on request, either by providing their name or by the C<':funcs'> and C<':all'> tags.
=cut
@EXPORT = ();
%EXPORT_TAGS = (
- 'funcs' => [ qw/flatten recall/ ]
+ 'funcs' => [ qw/flatten wrap recall/ ]
);
@EXPORT_OK = map { @$_ } values %EXPORT_TAGS;
$EXPORT_TAGS{'all'} = [ @EXPORT_OK ];
Vincent Pit, C<< <perl at profvince.com> >>, L<http://www.profvince.com>.
-You can contact me by mail or on #perl @ FreeNode (vincent or Prof_Vince).
+You can contact me by mail or on C<irc.perl.org> (vincent).
=head1 BUGS
-Please report any bugs or feature requests to C<bug-sub-prototype-util at rt.cpan.org>, or through the web interface at L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Sub-Prototype-Util>. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.
+Please report any bugs or feature requests to C<bug-sub-prototype-util at rt.cpan.org>, or through the web interface at L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Sub-Prototype-Util>.
+I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.
=head1 SUPPORT
=head1 COPYRIGHT & LICENSE
-Copyright 2008 Vincent Pit, all rights reserved.
+Copyright 2008,2009,2010,2011 Vincent Pit, all rights reserved.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
projects / perl / modules / Sub-Prototype-Util.git / blobdiff