bugfix: awk must consume *args*.

This problem happens when awk is issued from the command line
followed by one or more arguments as exemplified by the usage
txr -e '(awk ...) arg ... . In this case, after awk processes
the args as input sources and completes, TXR resumes
processing the command line arguments and wants to open arg
as a script file! To address this problem, when awk defaults
on using *args* as input sources, it consumes *args* by
clearing the variable to nil. TXR's command line processing
already reacts to changes in *args* by evaluated forms.
Code that wants *args* to be left alone by awk can explicitly
pass them in using (awk (:inputs *args*) ...).

* share/txr/stdlib/awk.tl (sys:awk-state): Move
default initialization of inputs into :postinit.
If there are no inputs by :postinit time, then
take *args* or *stdin*. If *args* is used in this
default manner, then consume *args*.

* txr.1: Documented.

2 files changed, 34 insertions, 1 deletions

diff --git a/share/txr/stdlib/awk.tl b/share/txr/stdlib/awk.tl
index 23db2403..a2fa0785 100644
--- a/share/txr/stdlib/awk.tl
+++ b/share/txr/stdlib/awk.tl
@@ -31,7 +31,7 @@
   fs ft kfs
   (ofs " ")
   (ors "\n")
-  (inputs (or *args* (list *stdin*)))
+  (inputs)
   (output *stdout*)
   (file-num 0)
   (file-rec-num 0)
@@ -44,6 +44,7 @@
     (dohash (k v self.streams)
       (close-stream v)))
   (:postinit (self)
+    (set self.inputs (or self.inputs (zap *args*) (list *stdin*)))
     (if (plusp self.rng-n)
       (set self.rng-vec (vector self.rng-n)))
     (unless (streamp self.output)
diff --git a/txr.1 b/txr.1
index 507d3f0a..94bc81c7 100644
--- a/txr.1
+++ b/txr.1
@@ -41383,6 +41383,38 @@ is taken as the input sources. Otherwise, the
 .code *stdin*
 stream is taken as the one and only input source.
 
+If the
+.code awk
+macro uses
+.code *args*
+via the above defaulting behavior, it copies
+.code *args*
+and sets that variable to
+.codn nil .
+This is done in order that if
+.code awk
+is used from the \*(TX command line, for example using the
+.code -e
+command line option, after
+.code awk
+terminates, \*(TX will not try to open the next argument
+as a script file or treat it as an option.
+Note: programs which want
+.code awk
+not to modify
+.code *args*
+can explicitly specify
+.code *args*
+as the argument to the
+.code :inputs
+keyword, rather than allow
+.code *args*
+to be used through the defaulting behavior. Only the
+defaulting behavior consumes the arguments by overwriting
+.code *args*
+with
+.codn nil .
+
 It is an error to specify more than one
 .code :inputs
 clause.