Item.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/Item.pm

# Copyright (C) 2003-2012 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::Item;

use 5.006;
use strict;
use Carp;
use Automake::ChannelDefs;
use Automake::DisjConditions;

=head1 NAME

Automake::Item - base class for Automake::Variable and Automake::Rule

=head1 DESCRIPTION

=head2 Methods

=over 4

=item C<new Automake::Item $name>

Create and return an empty Item called C<$name>.

=cut

sub new ($$)
{
  my ($class, $name) = @_;
  my $self = {
    name => $name,
    defs => {},
    conds => {},
  };
  bless $self, $class;
  return $self;
}

=item C<$item-E<gt>name>

Return the name of C<$item>.

=cut

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

=item C<$item-E<gt>def ($cond)>

Return the definition for this item in condition C<$cond>, if it
exists.  Return 0 otherwise.

=cut

sub def ($$)
{
  # This method is called very often, so keep it small and fast.  We
  # don't mind the extra undefined items introduced by lookup failure;
  # avoiding this with 'exists' means doing two hash lookup on
  # success, and proved worse on benchmark.
  my $def = $_[0]->{'defs'}{$_[1]};
  return defined $def && $def;
}

=item C<$item-E<gt>rdef ($cond)>

Return the definition for this item in condition C<$cond>.  Abort with
an internal error if the item was not defined under this condition.

The I<r> in front of C<def> stands for I<required>.  One
should call C<rdef> to assert the conditional definition's existence.

=cut

sub rdef ($$)
{
  my ($self, $cond) = @_;
  my $d = $self->def ($cond);
  prog_error ("undefined condition '" . $cond->human . "' for '"
	      . $self->name . "'\n" . $self->dump)
    unless $d;
  return $d;
}

=item C<$item-E<gt>set ($cond, $def)>

Add a new definition to an existing item.

=cut

sub set ($$$)
{
  my ($self, $cond, $def) = @_;
  $self->{'defs'}{$cond} = $def;
  $self->{'conds'}{$cond} = $cond;
}

=item C<$var-E<gt>conditions>

Return an L<Automake::DisjConditions> describing the conditions that
that an item is defined in.

These are all the conditions for which is would be safe to call
C<rdef>.

=cut

sub conditions ($)
{
  my ($self) = @_;
  prog_error ("self is not a reference")
    unless ref $self;
  return new Automake::DisjConditions (values %{$self->{'conds'}});
}

=item C<@missing_conds = $var-E<gt>not_always_defined_in_cond ($cond)>

Check whether C<$var> is always defined for condition C<$cond>.
Return a list of conditions where the definition is missing.

For instance, given

  if COND1
    if COND2
      A = foo
      D = d1
    else
      A = bar
      D = d2
    endif
  else
    D = d3
  endif
  if COND3
    A = baz
    B = mumble
  endif
  C = mumble

we should have (we display result as conditional strings in this
illustration, but we really return DisjConditions objects):

  var ('A')->not_always_defined_in_cond ('COND1_TRUE COND2_TRUE')
    => ()
  var ('A')->not_always_defined_in_cond ('COND1_TRUE')
    => ()
  var ('A')->not_always_defined_in_cond ('TRUE')
    => ("COND1_FALSE COND3_FALSE")
  var ('B')->not_always_defined_in_cond ('COND1_TRUE')
    => ("COND1_TRUE COND3_FALSE")
  var ('C')->not_always_defined_in_cond ('COND1_TRUE')
    => ()
  var ('D')->not_always_defined_in_cond ('TRUE')
    => ()
  var ('Z')->not_always_defined_in_cond ('TRUE')
    => ("TRUE")

=cut

sub not_always_defined_in_cond ($$)
{
  my ($self, $cond) = @_;

  # Compute the subconditions where $var isn't defined.
  return
    $self->conditions
      ->sub_conditions ($cond)
	->invert
	  ->multiply ($cond);
}


1;

### Setup "GNU" style for perl-mode and cperl-mode.
## Local Variables:
## perl-indent-level: 2
## perl-continued-statement-offset: 2
## perl-continued-brace-offset: 0
## perl-brace-offset: 0
## perl-brace-imaginary-offset: 0
## perl-label-offset: -2
## cperl-indent-level: 2
## cperl-brace-offset: 0
## cperl-continued-brace-offset: 0
## cperl-label-offset: -2
## cperl-extra-newline-before-brace: t
## cperl-merge-trailing-else: nil
## cperl-continued-statement-offset: 2
## End:

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

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