Add a 'commandline' command for manipulating the current buffer (#6492)

* Add a 'commandline' command for manipulating the current buffer

from `executehostcommand` keybindings. Inspired by fish:
https://fishshell.com/docs/current/cmds/commandline.html

* Update to development reedline

Includes nushell/reedline#472

Co-authored-by: sholderbach <sholderbach@users.noreply.github.com>

crates/nu-command/src/core_commands/commandline.rs

@@ -0,0 +1,84 @@
+use nu_engine::CallExt;
+use nu_protocol::ast::Call;
+use nu_protocol::engine::ReplOperation;
+use nu_protocol::engine::{Command, EngineState, Stack};
+use nu_protocol::Category;
+use nu_protocol::IntoPipelineData;
+use nu_protocol::{PipelineData, ShellError, Signature, SyntaxShape, Value};
+
+#[derive(Clone)]
+pub struct Commandline;
+
+impl Command for Commandline {
+    fn name(&self) -> &str {
+        "commandline"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("commandline")
+            .switch(
+                "append",
+                "appends the string to the end of the buffer",
+                Some('a'),
+            )
+            .switch(
+                "insert",
+                "inserts the string into the buffer at the cursor position",
+                Some('i'),
+            )
+            .switch(
+                "replace",
+                "replaces the current contents of the buffer (default)",
+                Some('r'),
+            )
+            .optional(
+                "cmd",
+                SyntaxShape::String,
+                "the string to perform the operation with",
+            )
+            .category(Category::Core)
+    }
+
+    fn usage(&self) -> &str {
+        "View or modify the current command line input buffer"
+    }
+
+    fn search_terms(&self) -> Vec<&str> {
+        vec!["repl", "interactive"]
+    }
+
+    fn run(
+        &self,
+        engine_state: &EngineState,
+        stack: &mut Stack,
+        call: &Call,
+        _input: PipelineData,
+    ) -> Result<PipelineData, ShellError> {
+        if let Some(cmd) = call.opt::<Value>(engine_state, stack, 0)? {
+            let mut ops = engine_state
+                .repl_operation_queue
+                .lock()
+                .expect("repl op queue mutex");
+            ops.push_back(if call.has_flag("append") {
+                ReplOperation::Append(cmd.as_string()?)
+            } else if call.has_flag("insert") {
+                ReplOperation::Insert(cmd.as_string()?)
+            } else {
+                ReplOperation::Replace(cmd.as_string()?)
+            });
+            Ok(Value::Nothing { span: call.head }.into_pipeline_data())
+        } else if let Some(ref cmd) = *engine_state
+            .repl_buffer_state
+            .lock()
+            .expect("repl buffer state mutex")
+        {
+            Ok(Value::String {
+                val: cmd.clone(),
+                span: call.head,
+            }
+            .into_pipeline_data())
+        } else {
+            Ok(Value::Nothing { span: call.head }.into_pipeline_data())
+        }
+    }
+}

crates/nu-command/src/core_commands/mod.rs

@@ -1,5 +1,6 @@
 mod alias;
 mod ast;
+mod commandline;
 mod debug;
 mod def;
 mod def_env;
@@ -30,6 +31,7 @@ mod version;
 
 pub use alias::Alias;
 pub use ast::Ast;
+pub use commandline::Commandline;
 pub use debug::Debug;
 pub use def::Def;
 pub use def_env::DefEnv;