feat: implement exit status var

rust-toolchain.toml

@@ -1,3 +1,3 @@
 [toolchain]
-channel = "1.75.0"
+channel = "1.76.0"
 components = ["clippy", "rustfmt"]

src/parser.rs

@@ -708,10 +708,9 @@ fn parse_word_parts(
     preceded(ch('$'), |input| {
       if let Some(char) = input.chars().next() {
         // $$ - process id
-        // $? - last exit code
         // $# - number of arguments in $*
         // $* - list of arguments passed to the current process
-        if "$?#*".contains(char) {
+        if "$#*".contains(char) {
           return ParseError::fail(
             input,
             format!("${char} is currently not supported."),
@@ -753,7 +752,10 @@ fn parse_word_parts(
     }
 
     let (input, parts) = many0(or7(
-      map(first_escaped_char(mode), PendingPart::Char),
+      or(
+        map(tag("$?"), |_| PendingPart::Variable("?")),
+        map(first_escaped_char(mode), PendingPart::Char),
+      ),
       map(parse_command_substitution, PendingPart::Command),
       map(preceded(ch('$'), parse_env_var_name), PendingPart::Variable),
       |input| {
@@ -1419,11 +1421,6 @@ mod test {
       "$$",
       Err("$$ is currently not supported."),
     );
-    run_test(
-      parse_unquoted_word,
-      "$?",
-      Err("$? is currently not supported."),
-    );
     run_test(
       parse_unquoted_word,
       "$#",
@@ -1458,6 +1455,7 @@ mod test {
     run_test(parse_u32, "4294967296", Err("backtrace"));
   }
 
+  #[track_caller]
   fn run_test<'a, T: PartialEq + std::fmt::Debug>(
     combinator: impl Fn(&'a str) -> ParseResult<'a, T>,
     input: &'a str,
@@ -1466,6 +1464,7 @@ mod test {
     run_test_with_end(combinator, input, expected, "");
   }
 
+  #[track_caller]
   fn run_test_with_end<'a, T: PartialEq + std::fmt::Debug>(
     combinator: impl Fn(&'a str) -> ParseResult<'a, T>,
     input: &'a str,

src/shell/mod.rs

@@ -172,6 +172,7 @@ fn execute_sequential_list(
           }
           ExecuteResult::Continue(exit_code, changes, handles) => {
             state.apply_changes(&changes);
+            state.apply_env_var("?", &exit_code.to_string());
             final_changes.extend(changes);
             async_handles.extend(handles);
             // use the final sequential item's exit code
@@ -258,6 +259,7 @@ fn execute_sequence(
         let (exit_code, mut async_handles) = match first_result {
           ExecuteResult::Exit(_, _) => return first_result,
           ExecuteResult::Continue(exit_code, sub_changes, async_handles) => {
+            state.apply_env_var("?", &exit_code.to_string());
             state.apply_changes(&sub_changes);
             changes.extend(sub_changes);
             (exit_code, async_handles)

src/shell/test.rs

@@ -331,6 +331,30 @@ async fn env_variables() {
     .await;
 }
 
+#[tokio::test]
+async fn exit_code_var() {
+  TestBuilder::new()
+    .command(r#"echo $? ; echo $? ; false ; echo $?"#)
+    .assert_stdout("\n0\n1\n")
+    .run()
+    .await;
+  TestBuilder::new()
+    .command(r#"(false || echo $?) && echo $?"#)
+    .assert_stdout("1\n0\n")
+    .run()
+    .await;
+  TestBuilder::new()
+    .command(r#"! false && echo $?"#)
+    .assert_stdout("0\n")
+    .run()
+    .await;
+  TestBuilder::new()
+    .command(r#"(deno eval 'Deno.exit(25)') || echo $?"#)
+    .assert_stdout("25\n")
+    .run()
+    .await;
+}
+
 #[tokio::test]
 async fn sequential_lists() {
   TestBuilder::new()