load: load block value should be exit status.

When TXR executes a top-level program, such that it will
exit when the last form in that program terminates,
it simulates a load. There is a block named load visible,
and the program can evaluate a (return-from load <expr>).
The value of that <expr> is thrown away, and the
termination status is always unsuccessful.

In this patch, (return-from load <expr>) is made to work
such that the value of <expr> will determine the exit
status, according to the same interpretation that
(exit <expr>) would give to the value.

* sysif.[ch] (exit_wrap): Static function becomes external.

* txr.c (txr_main): In the cases where we execute a file
and return from main, we now call exit_wrap instead.
The termination status is not simply based on whether
the file was successfully read, but takes into account the
load block.

* tests/019/load-ret/{script.tl,bad.tl}: New files.

* tests/019/load-ret/load-ret.tl: New tests.

* txr.1: Documented.

1 files changed, 1 insertions, 1 deletions

diff --git a/sysif.c b/sysif.c
index b02ec607..6eedb011 100644
--- a/sysif.c
+++ b/sysif.c
@@ -220,7 +220,7 @@ static val daemon_wrap(val nochdir, val noclose)
 }
 #endif
 
-static val exit_wrap(val status)
+val exit_wrap(val status)
 {
   val self = lit("exit");
   int stat;