New awk variable: krs.

* share/txr/stdlib/awk.tl (sys:awk-state): New slot, krs.
(sys:awk-state loop): Use record-adapter if krs is true,
even if the default fs is in effect. Pass value of krs to
record-adapter function.
(sys:awk-let): Provide krs "awk variable" symbol macro.

* txr.1: Documented krs. Clarified semantics of rs being
those of both separation and termination.

2 files changed, 30 insertions, 7 deletions

diff --git a/share/txr/stdlib/awk.tl b/share/txr/stdlib/awk.tl
index ad5cbe35..bc5dc9dd 100644
--- a/share/txr/stdlib/awk.tl
+++ b/share/txr/stdlib/awk.tl
@@ -24,7 +24,7 @@
 ;; SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 (defstruct sys:awk-state ()
-  (rs "\n")
+  (rs "\n") krs
   fs ft kfs
   (ofs " ")
   (ors "\n")
@@ -86,12 +86,14 @@
         [beg-file-func aws])
       (unwind-protect
         (let* ((stin (if (streamp in) in (open-file in)))
-               (recin (if (equal aws.rs "\n")
+               (recin (if (and (equal aws.rs "\n")
+                               (not aws.krs))
                         stin
                         (record-adapter (if (regexp aws.rs)
                                           aws.rs
                                           (regex-compile aws.rs))
-                                        stin))))
+                                        stin
+                                        aws.krs))))
           (set aws.file-rec-num 0)
           (whilet ((rec (get-line recin)))
             (set aws.rec rec)
@@ -169,6 +171,7 @@
                 (fnr (qref ,aws-sym file-rec-num))
                 (arg (qref ,aws-sym file-num))
                 (rs (qref ,aws-sym rs))
+                (krs (qref ,aws-sym krs))
                 (fs (qref ,aws-sym fs))
                 (ft (qref ,aws-sym ft))
                 (kfs (qref ,aws-sym kfs))
diff --git a/txr.1 b/txr.1
index 7e5ce1e7..f73c370c 100644
--- a/txr.1
+++ b/txr.1
@@ -37733,11 +37733,15 @@ instantiated by the
 .code record-adapter
 function.
 
-The meaning of
+The regular expression pattern stored in
+.code rs
+is used to matches substrings in the input which separate or terminate records.
+Unless the
+.code krs
+variable is set true, the substrings which match
 .code rs
-is that it matches substrings in the input which separate records. Records
-consist of the non-matching extents between matches for
-.codn rs .
+are discarded and the records consist of the non-matching extents between
+them.
 
 The initial value of
 .code rs
@@ -37745,6 +37749,22 @@ is
 .strn "\en" :
 the newline character. This means that, by default, records are lines.
 
+If a match for the record separator occurs at the end of the stream,
+it is not considered to delimit an empty record, but acts as the
+terminator for the previous record.
+
+.coNP Variable @ krs
+.desc
+The awk variable
+.code krs
+stands for "keep record separator". It is a Boolean variable, initialized to
+.codn nil .
+
+If it is set to a true value, then the separating text matched
+by the pattern in the
+.code rs
+variable is retained as part of the preceding record rather than removed.
+
 .coNP Variable @ fs
 .desc
 The awk variable