5.27. script Filter
The general syntax is:
!block script ... !endblock
See Understanding Filter Interfaces, if necessary.
The script filter can be used to embed arbitrary Perl source code within an SDF document. This is useful for many things including:
- declaring Perl subroutines implementing SDF filters and macros
- accessing databases
- updating log files.
!block script printf STDERR "Hello world!\n"; !endblock
As arbitrary sections of Perl can be included and executed, the code can potentially cause harm. At the moment, the ability to update external files from within an SDF document is seen as a feature. However, a version of SDF which restricts the embedded Perl to "safe" operations would be nice.