My first reaction was also that it didn't look very clean. But after some admittedly cursory comparison of how you'd do something in TXR to a few existing scripts I have (some Perl, some awk, and some chaining Unix utilities), it doesn't look terrible, and maybe even good. I should emphasize this is based on like 30 minutes of looking at it though, not serious knowledge of how TXR works.
One part that seems nice is that it handles multi-line constructs in a way that isn't horrible. Perl and awk have a big complexity jump once you go past one-line records, and most of the traditional Unix utilities just don't handle them at all (stuff like cut/join/sort only works on single-line, delimited records). Since constructs like Perl's while(<INPUT>) stop automatically doing the Right Thing once you get multi-line records, the usual next stop is that you're manually maintaining a state machine.
One part that seems nice is that it handles multi-line constructs in a way that isn't horrible. Perl and awk have a big complexity jump once you go past one-line records, and most of the traditional Unix utilities just don't handle them at all (stuff like cut/join/sort only works on single-line, delimited records). Since constructs like Perl's while(<INPUT>) stop automatically doing the Right Thing once you get multi-line records, the usual next stop is that you're manually maintaining a state machine.