---------------------------------------------------------------------

next up previous contents
Next: Labeling and referencing Up: PADEL syntax Previous: Multiplex branch

---------------------------------------------------------------------

Exception handler

Exception handler is defined as a set of processes to be executed when some errors are detected while executing certain set of processes. These error-handling processes are written useing try tex2html_wrap_inline2540 catch . The syntax is probably obvious from the next example:

    try{
        for(x = 0, 1, 0.01){
            y = f(x) / g(x)
            print y
        }
    }catch(g(x) = 0){
        print 'Divided by 0!'
    }

The result is the following:

tex2html_wrap2542

The output PAD figure is as same as if statement. This is because there is no such concept as exception handler in PAD itself.

The rules for putting a return code and { } is as same as that of repetition and conditional branch. If the content of try or catch is in one line, you do not have to enclose the content with { }. You can add a return code before and after { or }, and you can put as many spaces as you like. Hence, the next example is valid.

    try
        print sty
    catch(str = NULL)
        print 'NULL!'
    
    try
    {
        print sty
    }
    catch (str = NULL) {
        print 'NULL!'
    }

The next example is invalid.

    try{  print sty  }
    catch(str = NULL)  print 'NULL!'

---------------------------------------------------------------------

Go back to pad2ps - automatic PAD drawer.
Go back to Seiichi Yoshida's Home Page.
Copyright(C) Seiichi Yoshida (comet@aerith.net). All rights reserved.
Sun Nov 10 01:36:04 JST 1996