Alt-CWB-ambs

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lib/CWB/CQP.pm  view on Meta::CPAN

  my $lines = @{$self->{'lines'}};
  return $lines            # output has already been buffered => ready to read
    if $lines > 0;
  return undef             # no command active => undefined state
    unless $self->{'command'};
  return $self->_update($timeout); # try to read from CQP process & return number of lines available (NB: line buffer was empty before)
}

## INTERNAL: reset internal status after command has been completed, check that there is no extra output
sub _eol {
  my $self = shift;
  while ($self->_update > 0) { 1 } # check for any pending output from CQP process
  carp "CWB::CQP:  Unexpected CQP output after end of command:\n",
    map {" | $_\n"} @{$self->{'lines'}},
      "(command was: ".$self->{'command'}.")"
        if @{$self->{'lines'}} > 0;
  $self->{'lines'} = [];
  $self->{'command'} = undef; # no active command now
}

lib/CWB/CQP.pm  view on Meta::CPAN

  my $debug = $self->{'debug'};

  $self->_update(-1)            # fill line buffer if necessary (blocking mode)
    unless @{$self->{'lines'}} > 0;

  my $line = shift @{$self->{'lines'}};
  if ($line eq '-::-EOL-::-') { 
    ## special line printed by ".EOL.;" marks end of CQP output
    print "CQP ", "-" x 60, "\n"
      if $debug;
    $self->_eol;
    return undef;               # undef return value marks end of output
  }
  else {
    print "CQP >> $line\n"
      if $debug;
    return $line;
  }
}

=item I<@lines> = I<$cqp>->B<getlines>(I<$n>);

lib/CWB/CQP.pm  view on Meta::CPAN

sub getlines {
  croak 'USAGE:  @lines = $cqp->getlines($n);'
    unless @_ == 2 and $_[1] =~ /^-?[0-9]+$/ and wantarray;
  my $self = shift;
  my $n_lines = shift;
  my @lines = ();
  if ($n_lines == 0) {
    while (my $line = shift @{$self->{'lines'}}) {
      if ($line eq '-::-EOL-::-') {
        $self->_eol;
        push @lines, undef;
      }
      else {
        push @lines, $line;
      }
    }
  }
  else {
    while ($n_lines != 0) {     # if $n_lines < 0, reads complete output of CQP command
      while ($n_lines != 0 and @{$self->{'lines'}} > 0) {
        my $line = shift @{$self->{'lines'}};
        if ($line eq '-::-EOL-::-') {
          $self->_eol;
          push @lines, undef;
          $n_lines = 0;
        }
        else {
          push @lines, $line;
          $n_lines--;
        }
      }
      $self->_update(-1)     # wait for CQP output to become available (in $self's input buffer)
        if $n_lines != 0;

lib/CWB/CQP.pm  view on Meta::CPAN

sub exec {
  croak 'USAGE:  $cqp->exec($cmd);'
    unless @_ == 2;
  my $self = shift;
  my $cmd = shift;
  my $debug = $self->{'debug'};

  $self->run($cmd);
  my @result = $self->getlines(-1);
  my $eol = pop @result;
  if (defined $eol) {
    die "CWB::CQP:  INTERNAL ERROR in _exec() -- missing 'undef' at end of command output (ignored)";
    push @result, $eol; # seems to be regular line, so push it back onto result list
  }
  return @result;
}

=item I<@fields> = I<$cqp>->B<getrow>;

=item I<@rows> = I<$cqp>->B<exec_rows>(I<$cmd>);

Convenience functions for reading TAB-delimited tables, which are generated by CQP commands such as B<count>, B<group>, B<tabulate> and B<show cd>.