status returns the function name when called with -u parameter

Fixes #1743

doc_src/status.txt

@@ -11,6 +11,7 @@ status is-no-job-control
 status is-full-job-control
 status is-interactive-job-control
 status current-filename
+status current-function
 status current-line-number
 status print-stack-trace
 status job-control CONTROL-TYPE
@@ -38,6 +39,8 @@ The following operations (sub-commands) are available:
 
 - `current-filename` prints the filename of the currently running script. Also `-f` or `--current-filename`.
 
+- `current-function` prints the name of the currently called function if able, when missing displays "Not a function". Also `-u` or `--current-function`.
+
 - `current-line-number` prints the line number of the currently running script. Also `-n` or `--current-line-number`.
 
 - `job-control CONTROL-TYPE` sets the job control type, which can be `none`, `full`, or `interactive`. Also `-j CONTROL-TYPE` or `--job-control=CONTROL-TYPE`.

src/builtin.cpp

@@ -2368,6 +2368,7 @@ enum status_cmd_t {
     STATUS_IS_INTERACTIVE_JOB_CTRL,
     STATUS_IS_NO_JOB_CTRL,
     STATUS_CURRENT_FILENAME,
+    STATUS_CURRENT_FUNCTION,
     STATUS_CURRENT_LINE_NUMBER,
     STATUS_SET_JOB_CONTROL,
     STATUS_PRINT_STACK_TRACE,
@@ -2376,6 +2377,7 @@ enum status_cmd_t {
 // Must be sorted by string, not enum or random.
 const enum_map<status_cmd_t> status_enum_map[] = {
     {STATUS_CURRENT_FILENAME, L"current-filename"},
+    {STATUS_CURRENT_FUNCTION, L"current-function"},
     {STATUS_CURRENT_LINE_NUMBER, L"current-line-number"},
     {STATUS_IS_BLOCK, L"is-block"},
     {STATUS_IS_COMMAND_SUB, L"is-command-substitution"},
@@ -2608,6 +2610,14 @@ static int builtin_status(parser_t &parser, io_streams_t &streams, wchar_t **arg
             streams.out.append_format(L"%ls\n", fn);
             break;
         }
+        case STATUS_CURRENT_FUNCTION: {
+            CHECK_FOR_UNEXPECTED_STATUS_ARGS(status_cmd)
+            const wchar_t *fn = parser.get_function_name();
+
+            if (!fn) fn = _(L"Not a function");
+            streams.out.append_format(L"%ls\n", fn);
+            break;
+        }
         case STATUS_CURRENT_LINE_NUMBER: {
             CHECK_FOR_UNEXPECTED_STATUS_ARGS(status_cmd)
             streams.out.append_format(L"%d\n", parser.get_lineno());

src/parser.cpp

@@ -440,6 +440,10 @@ const wchar_t *parser_t::is_function() const {
     return result;
 }
 
+const wchar_t *parser_t::get_function_name() {
+    return this->is_function();
+}
+
 int parser_t::get_lineno() const {
     int lineno = -1;
     if (!execution_contexts.empty()) {

src/parser.h

@@ -306,6 +306,9 @@ class parser_t {
     /// Return a description of the given blocktype.
     const wchar_t *get_block_desc(int block) const;
 
+    /// Return the current function name.
+    const wchar_t *get_function_name();
+
     /// Removes a job.
     bool job_remove(job_t *job);
 

tests/status.in

@@ -39,3 +39,13 @@ status --job-control=1none
 
 # Now set it to a valid mode.
 status job-control none
+
+# Check status -u outside functions
+status current-function
+
+function test_function
+    status current-function
+end
+
+test_function
+eval test_function

tests/status.out

@@ -0,0 +1,3 @@
+Not a function
+test_function
+test_function