Trait CommandHandler 

pub trait CommandHandler: Command {
    // Required method
    fn execute(
        &self,
        runtime: &mut SessionRuntime<'_>,
        args: &CommandContext,
    ) -> CommandResult;
}

Command execution trait.

Commands that can be executed implement this trait in addition to Command.

Design Philosophy

Separating execution from metadata allows:

• Querying command info without execution capability
• Different execution strategies (sync, async, background)
• Testing command metadata independently

Session Runtime

Commands receive a SessionRuntime which provides access to:

• ModeApi - Mode stack operations (push, pop, set)
• BufferApi - Buffer content and cursor operations
• WindowApi - Window management and focus
• ExtensionApi - Per-session module state
• ChangeTracker - State change accumulation

For operations not yet covered by these APIs, use the escape hatch:

let kernel = runtime.kernel();
let buffer = kernel.buffers.get(buffer_id)?;

Example

use reovim_driver_command::{Command, CommandHandler, CommandContext, CommandResult};
use reovim_driver_session::{SessionRuntime, ModeApi, TransitionContext};
use reovim_kernel::api::v1::{CommandId, ModuleId};

struct EnterInsertMode;

impl Command for EnterInsertMode {
    fn id(&self) -> CommandId {
        CommandId::new(ModuleId::new("vim"), "enter-insert-mode")
    }
    fn description(&self) -> &'static str { "Enter insert mode" }
}

impl CommandHandler for EnterInsertMode {
    fn execute(&self, runtime: &mut SessionRuntime<'_>, _args: &CommandContext) -> CommandResult {
        let insert_mode = ModeId::new(ModuleId::new("vim"), "insert");
        runtime.set_mode(insert_mode, TransitionContext::new());
        CommandResult::Success
    }
}

Required Methods

fn execute( &self, runtime: &mut SessionRuntime<'_>, args: &CommandContext, ) -> CommandResult

Execute the command.

Arguments

• runtime - Session runtime providing API trait access and kernel escape hatch
• args - The command arguments parsed from user input

Returns

A CommandResult indicating success, error, or special results like quit.

Implementors