[j-nsp] terminate endless loop in SLAX

[Martin T]

On Tue, Jun 26, 2018 at 9:35 PM Phil Shafer <phil at juniper.net> wrote:
>
> Martin T writes:
> >Thanks Phil! So in short, at the moment "terminate" statement inside
> >the while loop works in a way that when "terminate" statement is
> >executed, then immediately next iteration of while loop is started if
> >while expression returns true and this will loop infinitely? If this
> >while expression returns false, then terminate statement was the last
> >thing processed by the script and script exits. At least based on my
> >tests it seems to work like that.
>
> Yes, which does inspire a reasonable (if ugly) workaround:
>
> Bock % cat /tmp/foo.slax
> version 1.2;
>
> match / {
>     mvar $working = true();
>
>     <op-script-results> {
>         while ($working) {
>             set $working = false();
>             terminate "doa";
>         }
>     }
> }
> Bock % slaxproc -E -g /tmp/foo.slax
> doa
> <?xml version="1.0"?>
> <op-script-results/>
> Bock %
>
> Hope this helps.
>
> Thanks,
>  Phil

Heh, I thought about exactly the same workaround. I have a script with
multiple custom functions and if the function needs to terminate, then
it returns a number and if it does not need to terminate, then it
returns a string. In main match template inside the "while ( $chars )"
loop I check this with:

set $x = example:foo($i);
if ( exsl:object-type($x) == "number" ) {
    set $chars = "";
    terminate "Terminated on iteration #" _ $x;
}

Other functions I return a string in case I want the main match
template to terminate and check this with something similar:

set $x = example:bar($i);
if ( exsl:object-type($x) == "string" ) {
    set $chars = "";
    terminate "Terminated";
}

While this is indeed hackish, then as much as I tested, it seems to work fine.


Martin