Worked out way of protecting $_ variable.

- Remove Bugs section from README.

- Add new basta_uln_save global variable. We don't
  have to preserve its value across reloads since it
  is only temporarily used.

- The ALRM and WINCH traps set up by basta.install_hooks
  are now three-command sequences which save $_ into
  the global, then run the handler, and the restore
  it using a trick involving the : null command.

2 files changed, 2 insertions, 8 deletions

diff --git a/README.md b/README.md
index 1b6d977..abff3d7 100644
--- a/README.md
+++ b/README.md
@@ -75,9 +75,3 @@ See the license block at the bottom of the file.
 The second clause says that any binary code (as if that would
 exist for shell customization code, ha!) is not required to
 carry any copyright notice.
-
-## Bugs
-
-The `$_` variable, which holds the last argument of the previous
-command, is unreliable under Basta. It gets clobbered by the dispatch
-of the signal trap handler refreshes the status line.
diff --git a/basta.sh b/basta.sh
index a279190..61527ff 100644
--- a/basta.sh
+++ b/basta.sh
@@ -8,6 +8,7 @@ basta_scroll_lines=${basta_scroll_lines-0}
 basta_prev_reserved_rows=${basta_prev_reserved_rows-}
 
 basta_status_alarm_pid=${basta_status_alarm_pid-}
+basta_uln_save=
 
 basta.query_terminal_lines()
 {
@@ -136,8 +137,7 @@ basta.alarm_timer()
 
 basta.install_hooks()
 {
-  trap basta.update_status ALRM
-  trap basta.update_status WINCH
+  trap 'basta_uln_save=$_; basta.update_status; : "$basta_uln_save"' ALRM WINCH
   trap basta.cleanup EXIT
   PROMPT_COMMAND='basta.initial_prompt_hook'
 }