Perl Data Filter

Perl based data filter passes all selected buffers to a Perl script where the data can be manipulated. When the script has finished the data will be returned to Plot as new data buffers. Plot builds an easy to access framework arround your script which allow to pass the data to Plot. Errors produced by the script will be shown in the console of the Macro Inspector.

To create a Perl data filter open the Macro Inspector choose Add in the panel an select Perl Filter as type. In the large text field of the Macro Inspector you can now enter your script.

Predefinitions

The following variables and subroutines are available in your Perl import filter:

&log()

Send output to the console in the Macro Inspector.

@data[buffer][point number][column]

A three dimensional array which contain the data of all selected buffers at the beginning of the script. At the end of the script the array will be returned to Plot
[buffer]: The number of the buffer (starting with 0)
[point number]: The number of the data point (starting with 0)
[column]: The column number (0 = X value, 1 = Y value, 2 = X error, 3 = Y error)

@commnet[buffer]

This array you contain the comments of your buffers.

@source[buffer]

This array you contain the source information of your buffers

$nb

The number of buffers passed to the script.

%var{key}

If the script is started from a macro this hash contains all number variables. The variables will also be returned to the macro.

%svar{key}

If the script is started from a macro this hash contains all string varibles. The variables will also be returned to the macro.

Restrictions

  • Do not send anything to STDERR and STDOUT.
  • Do not use any interactive things.
  • If your Perl script hangs Plot will hang too (sorry, this has to be changed in the future). You can kill a hanging Perl script from the Terminal.app

Example

The following example demonstrates how to apply manipulations to your buffers (in this case 1.23 will be added to the Y values and a string will be appended to the comment field).

 for ($j=0;$j<$nb;$j++) {
   $np=$#{$data[$j]}+1;
   $nc=$#{$data[$j][0]}+1;
   for ($i=0;$i<$np;$i++) {
     $data[$j][$i][1]+=1.23;
   }
   $comment[$j].=" added 1.23";
 }