Allow exporting extern-wrapped (#10025)

crates/nu-cmd-lang/src/core_commands/export_extern_wrapped.rs

@@ -0,0 +1,56 @@
+use nu_protocol::ast::Call;
+use nu_protocol::engine::{Command, EngineState, Stack};
+use nu_protocol::{Category, Example, PipelineData, ShellError, Signature, SyntaxShape, Type};
+
+#[derive(Clone)]
+pub struct ExportExternWrapped;
+
+impl Command for ExportExternWrapped {
+    fn name(&self) -> &str {
+        "export extern-wrapped"
+    }
+
+    fn usage(&self) -> &str {
+        "Define an extern with a custom code block and export it from a module."
+    }
+
+    fn signature(&self) -> nu_protocol::Signature {
+        Signature::build("export extern-wrapped")
+            .input_output_types(vec![(Type::Nothing, Type::Nothing)])
+            .required("def_name", SyntaxShape::String, "definition name")
+            .required("params", SyntaxShape::Signature, "parameters")
+            .required("body", SyntaxShape::Block, "wrapper code block")
+            .category(Category::Core)
+    }
+
+    fn extra_usage(&self) -> &str {
+        r#"This command is a parser keyword. For details, check:
+  https://www.nushell.sh/book/thinking_in_nu.html"#
+    }
+
+    fn is_parser_keyword(&self) -> bool {
+        true
+    }
+
+    fn run(
+        &self,
+        _engine_state: &EngineState,
+        _stack: &mut Stack,
+        _call: &Call,
+        _input: PipelineData,
+    ) -> Result<PipelineData, ShellError> {
+        Ok(PipelineData::empty())
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Export the signature for an external command",
+            example: r#"export extern-wrapped my-echo [...rest] { echo $rest }"#,
+            result: None,
+        }]
+    }
+
+    fn search_terms(&self) -> Vec<&str> {
+        vec!["signature", "module", "declare"]
+    }
+}

crates/nu-cmd-lang/src/core_commands/mod.rs

@@ -15,6 +15,7 @@ mod export_const;
 mod export_def;
 mod export_def_env;
 mod export_extern;
+mod export_extern_wrapped;
 mod export_module;
 mod export_use;
 mod extern_;
@@ -55,6 +56,7 @@ pub use export_const::ExportConst;
 pub use export_def::ExportDef;
 pub use export_def_env::ExportDefEnv;
 pub use export_extern::ExportExtern;
+pub use export_extern_wrapped::ExportExternWrapped;
 pub use export_module::ExportModule;
 pub use export_use::ExportUse;
 pub use extern_::Extern;

crates/nu-cmd-lang/src/default_context.rs

@@ -33,6 +33,7 @@ pub fn create_default_context() -> EngineState {
             ExportDef,
             ExportDefEnv,
             ExportExtern,
+            ExportExternWrapped,
             ExportUse,
             ExportModule,
             Extern,