Location.pm

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Author : Stefano Lattarini
Date : 2012-03-04 15:44:46
Hash : 7df05a0b
Message : maint: require perl 5.6 throughout That version of perl is quite old already, so it should be OK to require it. More importantly, it is the older perl versions the developers can currently use for testing, thus it's safer and more honest to just require it throughout. And anyway, we were already requiring it in Automake::Getopt, which implied that both automake and aclocal wouldn't have worked in practice with an older perl version. See also the discussion related to automake bug#10925. * lib/Automake/ChannelDefs.pm: Adjusted to require perl 5.6. * lib/Automake/Channels.pm: Likewise. * lib/Automake/Condition.pm: Likewise. * lib/Automake/Configure_ac.pm: Likewise. * lib/Automake/DisjConditions.pm: Likewise. * lib/Automake/FileUtils.pm: Likewise. * lib/Automake/General.pm: Likewise. * lib/Automake/Item.pm: Likewise. * lib/Automake/ItemDef.pm: Likewise. * lib/Automake/Location.pm: Likewise. * lib/Automake/Options.pm: Likewise. * lib/Automake/Rule.pm: Likewise. * lib/Automake/RuleDef.pm: Likewise. * lib/Automake/Struct.pm: Likewise. * lib/Automake/VarDef.pm: Likewise. * lib/Automake/Variable.pm: Likewise. * lib/Automake/Version.pm: Likewise. * lib/Automake/Wrap.pm: Likewise. * lib/Automake/XFile.pm: Likewise.

lib/Automake/Location.pm

# Copyright (C) 2002-2012 Free Software Foundation, Inc.

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2, or (at your option)
# any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

package Automake::Location;

use 5.006;

=head1 NAME

Automake::Location - a class for location tracking, with a stack of contexts

=head1 SYNOPSIS

  use Automake::Location;

  # Create a new Location object
  my $where = new Automake::Location "foo.c:13";

  # Change the location
  $where->set ("foo.c:14");

  # Get the location (without context).
  # Here this should print "foo.c:14"
  print $where->get, "\n";

  # Push a context, and change the location
  $where->push_context ("included from here");
  $where->set ("bar.h:1");

  # Print the location and the stack of context (for debugging)
  print $where->dump;
  # This should display
  #   bar.h:1:
  #   foo.c:14:   included from here

  # Get the contexts (list of [$location_string, $description])
  for my $pair (reverse $where->contexts)
    {
      my ($loc, $descr) = @{$pair};
      ...
    }

  # Pop a context, and reset the location to the previous context.
  $where->pop_context;

  # Clone a Location.  Use this when storing the state of a location
  # that would otherwise be modified.
  my $where_copy = $where->clone;

  # Serialize a Location object (for passing through a thread queue,
  # for example)
  my @array = $where->serialize ();

  # De-serialize: recreate a Location object from a queue.
  my $where = new Automake::Location::deserialize ($queue);

=head1 DESCRIPTION

C<Location> objects are used to keep track of locations in Automake,
and used to produce diagnostics.

A C<Location> object is made of two parts: a location string, and
a stack of contexts.

For instance if C<VAR> is defined at line 1 in F<bar.h> which was
included at line 14 in F<foo.c>, then the location string should be
C<"bar.h:10"> and the context should be the pair (C<"foo.c:14">,
C<"included from here">).

Section I<SYNOPSIS> shows how to setup such a C<Location>, and access
the location string or the stack of contexts.

You can pass a C<Location> to C<Automake::Channels::msg>.

=cut

=head2 Methods

=over

=item C<$where = new Automake::Location ([$position])>

Create and return a new Location object.

=cut

sub new ($;$)
{
  my ($class, $position) = @_;
  my $self = {
    position => $position,
    contexts => [],
  };
  bless $self, $class;
  return $self;
}

=item C<$location-E<gt>set ($position)>

Change the location to be C<$position>.

=cut

sub set ($$)
{
  my ($self, $position) = @_;
  $self->{'position'} = $position;
}

=item C<$location-E<gt>get>

Get the location (without context).

=cut

sub get ($)
{
  my ($self) = @_;
  return $self->{'position'};
}

=item C<$location-E<gt>push_context ($context)>

Push a context to the location.

=cut

sub push_context ($$)
{
  my ($self, $context) = @_;
  push @{$self->{'contexts'}}, [$self->get, $context];
  $self->set (undef);
}

=item C<$where = $location-E<gt>pop_context ($context)>

Pop a context, and reset the location to the previous context.

=cut

sub pop_context ($)
{
  my ($self) = @_;
  my $pair = pop @{$self->{'contexts'}};
  $self->set ($pair->[0]);
  return @{$pair};
}

=item C<@contexts = $location-E<gt>get_contexts>

Return the array of contexts.

=cut

sub get_contexts ($)
{
  my ($self) = @_;
  return @{$self->{'contexts'}};
}

=item C<$location = $location-E<gt>clone>

Clone a Location.  Use this when storing the state of a location
that would otherwise be modified.

=cut

sub clone ($)
{
  my ($self) = @_;
  my $other = new Automake::Location ($self->get);
  my @contexts = $self->get_contexts;
  for my $pair (@contexts)
    {
      push @{$other->{'contexts'}}, [@{$pair}];
    }
  return $other;
}

=item C<$res = $location-E<gt>dump>

Print the location and the stack of context (for debugging).

=cut

sub dump ($)
{
  my ($self) = @_;
  my $res = ($self->get || 'INTERNAL') . ":\n";
  for my $pair (reverse $self->get_contexts)
    {
      $res .= $pair->[0] || 'INTERNAL';
      $res .= ": $pair->[1]\n";
    }
  return $res;
}

=item C<@array = $location-E<gt>serialize>

Serialize a Location object (for passing through a thread queue,
for example).

=cut

sub serialize ($)
{
  my ($self) = @_;
  my @serial = ();
  push @serial, $self->get;
  my @contexts = $self->get_contexts;
  for my $pair (@contexts)
    {
      push @serial, @{$pair};
    }
  push @serial, undef;
  return @serial;
}

=item C<new Automake::Location::deserialize ($queue)>

De-serialize: recreate a Location object from a queue.

=cut

sub deserialize ($)
{
  my ($queue) = @_;
  my $position = $queue->dequeue ();
  my $self = new Automake::Location $position;
  while (my $position = $queue->dequeue ())
    {
      my $context = $queue->dequeue ();
      push @{$self->{'contexts'}}, [$position, $context];
    }
  return $self;
}

=back

=head1 SEE ALSO

L<Automake::Channels>

=head1 HISTORY

Written by Alexandre Duret-Lutz E<lt>F<adl@gnu.org>E<gt>.

=cut

1;

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kc3-lang/automake/lib/Automake/Location.pm

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kc3-lang/automake /lib/Automake/Location.pm