awk macro: use range test logic for clause conditions.

* share/txr/stdlib/awk.tl (sys:range-test): Function renamed
to sys:awk-test, since it's not just for ranges.
(sys:awk-let): Uses of sys:range-test follow rename.
sys:awk-test introduced into expansion of cond parts
of cond-action clauses.

* txr.1: Documented new behavior (conditions can produce
a function or regex, which is implicitly invoked on rec).

2 files changed, 16 insertions, 5 deletions

diff --git a/share/txr/stdlib/awk.tl b/share/txr/stdlib/awk.tl
index eccef632..466ab544 100644
--- a/share/txr/stdlib/awk.tl
+++ b/share/txr/stdlib/awk.tl
@@ -110,7 +110,7 @@
     (t (put-string self.rec)
        (put-string self.ors))))
 
-(defun sys:range-test (val rec)
+(defun sys:awk-test (val rec)
   (caseq (typeof val)
     ((regex fun) (call val rec))
     (t val)))
@@ -200,8 +200,8 @@
                           (qref ,awc rng-exprs))
                     rng-temp))
                 (rng (from-expr to-expr)
-                  ^(sys:rng (sys:range-test ,from-expr ,(qref ,awc rng-rec-temp))
-                            (sys:range-test ,to-expr ,(qref ,awc rng-rec-temp))))
+                  ^(sys:rng (sys:awk-test ,from-expr ,(qref ,awc rng-rec-temp))
+                            (sys:awk-test ,to-expr ,(qref ,awc rng-rec-temp))))
                 (ff (. opip-args)
                   ^(symacrolet ((f (rslot ,',aws-sym 'fields 'f-to-rec)))
                      (set f [(opip ,*opip-args) f])))
@@ -215,7 +215,8 @@
 (defmacro awk (:env e . clauses)
   (let ((awc (sys:awk-expander clauses)))
     (with-gensyms (aws-sym awk-begf-fun awk-fun awk-endf-fun awk-retval)
-      (let* ((p-actions-xform-unex (mapcar (aret ^(when ,@1 ,*@rest))
+      (let* ((p-actions-xform-unex (mapcar (aret ^(when (sys:awk-test ,@1 rec)
+                                                    ,*@rest))
                                            awc.cond-actions))
              (p-actions-xform (sys:expand
                                 ^(sys:awk-let ,awc ,aws-sym
diff --git a/txr.1 b/txr.1
index d57dd04f..b77f6b52 100644
--- a/txr.1
+++ b/txr.1
@@ -38320,7 +38320,17 @@ variable, and various
 variables are updated. Then, the condition-action clauses are processed, in the order
 in which they appear. Each
 .meta condition
-is evaluated. If it yields true, then its associated
+is evaluated. If the resulting value is a regular expression
+or a function, then this regular expression or function is invoked on the value
+stored in the record variable
+.codn rec ,
+and the result is taken to be the truth value of
+.metn condition .
+Otherwise, if the resulting value of
+.meta condition
+is other than a function or regular expression, it is taken directly
+to be the truth value.
+If the condition is true, then its associated
 .meta action
 forms are evaluated. Either way, processing passes to the next condition
 clause (unless an explicit step is taken in one of the