awk: new feature: again operator.

* share/txr/stdlib/awk.tl (sys:awk-state loop):
Wrap a loop around around the two forms that
split the record into fields and dispatch the main
rule function. The loop repeats if the named
block returns :awk-again.
(sys:awk-mac-let): New local macro (again)
which bails out of the :awk-rec block just like (next) does,
but specifies :awk-again as the return value.

* txr.1: Documented.

1 files changed, 3 insertions, 3 deletions

diff --git a/share/txr/stdlib/awk.tl b/share/txr/stdlib/awk.tl
index 5b19e706..b0f54aaf 100644
--- a/share/txr/stdlib/awk.tl
+++ b/share/txr/stdlib/awk.tl
@@ -172,9 +172,8 @@
               (set aws.rec rec aws.orig-rec rec)
               (inc aws.rec-num)
               (inc aws.file-rec-num)
-              aws.(rec-to-f)
-              (block :awk-rec
-                [func aws]))
+              (while* (eq :awk-again (block :awk-rec [func aws]))
+                aws.(rec-to-f)))
             (when end-file-func
               [end-file-func aws])))))))
 
@@ -294,6 +293,7 @@
                 (ofs (qref ,aws-sym ofs))
                 (ors (qref ,aws-sym ors)))
      (macrolet ((next () '(return-from :awk-rec))
+                (again () '(return-from :awk-rec :awk-again))
                 (next-file () '(return-from :awk-file))
                 (sys:rng (form from-expr to-expr :env e)
                   (let ((style (car form))