Revert the bespoke __prompt()/__prompt2() function mechanism from issue
#09 and return to stock Lua's _PROMPT/_PROMPT2 globals (which already
support dynamic prompts via __tostring metatables). Set default
_PROMPT = "lush> " in doREPL if not already defined by config.
Replace static _PROMPT/_PROMPT2 with dynamic __prompt(exitcode)/__prompt2(exitcode)
functions. Fallback chain: __prompt() → _PROMPT → "> ". Install a default __prompt
that shows the current directory with ~ abbreviation. Track last exit code from the
REPL loop and pass it to the prompt function.
Add !command syntax that runs commands with inherited terminal (no
capture). The lexer treats ! as a statement-starting token, reading
to end-of-line with the same interpolation/escape/pipe support as
backtick commands. The C function sets _ = {code=N, stdout="", stderr=""}.
Add split_pipeline() to split command strings on unquoted | and
exec_pipeline() to fork N children connected by inter-stage pipes.
Only the last stage's stdout/stderr are captured; middle stages'
stderr is inherited. Exit code comes from the last stage.
Redesign issue #10: bare-word commands now work in both scripts and
the REPL via a parser-level heuristic (identifier + non-exception-list
token → shell command). Add runtime fallback for string-arg syntax
(echo "hello"), double-dash flag handling, and classification examples.
Add issue #12 for path-based command execution (./script, /bin/ls, ~/bin/deploy).
Add testes/lush/commands-interactive.lua as a design playground covering
result table structure, exit codes, commands inside Lua blocks, _ behaviour,
runtime fallback, Lua variable shadowing, and interleaved Lua/shell.
Use sigsetjmp/siglongjmp to catch SIGINT during readline/fgets input
and jump back to the REPL loop with a fresh prompt. Running Lua code
still gets interrupted via the existing laction/lstop mechanism.
Fixes#11.
Rewrite #10 with refined interactive command design: bare-word REPL
fallback instead of ! prefix, result table assigned to _, same shape
as captured commands. Add #11 for Ctrl-C clearing the current line
instead of exiting the REPL.
Mark issues #02 (backtick lexing/parsing), #03 (command execution
runtime), and #04 (argv parsing) as resolved. Add new issues for
configuration (#08), programmable prompt (#09), and interactive
command execution (#10).
