General remarks

• There is a Perl startup file: /online_dir/TkIrc.pl. The file was originally invented to do the initialisations for online -tki. However it turned out that it is also necessary for the other Online sessions. Among other things, TkIrc.pl loads the Tango configuration file online.xml. See the online -tki manual for more informations about TkIrc.pl.

• There is no change in the Spectra command line syntax. All gra-files execute as before.

• gra-style commands can be executed from within Perl:

  Gra_command( "create test 0 10 100") or die "error message";
  

• All arrays begin at index 0. Spectra uses the Fortran convention (arrays begin at index 1) because most scientific programs were written in Fortran when Spectra was launched. That means in Spectra the first y-value of a Scan GQE (graphical queue element) is accessed by SPECTRA> test(1) = 12. In Perl-Spectra we write (taken from the example 10.10.2 ):

    use Spectra; 
    use GQE; 
  
    $t1 = SCAN->create( name => "t1", 
                        start => "0", 
                        stop => "10", 
                        np => "$size") or die " Failed to create t1 "; 
    #
    # ... set the y-values to sinus() ...
    #
    for $i (0 .. ($size - 1))
    {
        $t1->{y}[$i] = sin( $t1->{x}[$i]);
    }
  

  Notice that $i starts at 0.

• GQE parameters are changed or retrieved by the methods set or get.

    use Spectra; 
    use GQE;
  
    $t1 = TEXT->create( name => 'test'); 
    $col = $t1->get( 'colour'); 
    $ret = $t1->set( string => 'ein Text', colour => 'red');