xous-core/apps/repl

REPL

A simple demo application that provides a bare-bones REPL framework.

Copying This Demo to a New App

1. Add a UX context by editing services/gam/src/lib.rs/EXPECTED_BOOT_CONTEXTS
2. Copy this demo application, and rename the relevant structures in its Cargo.toml and main.rs.
3. Add it to the Workspace default-members and members arrays by editing ./Cargo.toml
4. Add it to the build by editing xtask/src/main.rs and inserting it into the relevant descriptor. Typically, you would insert your app into the hw_pkgs array, as this is what is built and targeted for full hardware builds. Most of the other trimmed-down descriptors are for debug, emulation, and benchmarking.
5. (optional) You may also need to run cargo xtask generate-locales if you modify/add any internationalization strings.
6. Add entries to the app switching menu. services/status/src/appmenu.rs to add the menu item (plus locales/i18n.json in the status directory if you want translated names for the app), and services/status/src/main.rs to add the Opcode (inside the StatusOpcode struct, around line 55) and the actual operation itself (in the main loop, around line 670).

Details

repl is a baseline demo application for Xous. It uses a chat-client style interface (stacking bubbles of text, with user input right-aligned and shell feedback left-aligned) to facilitate interactions.

It implements the basic envisioned structure of a Xous application, namely:

• Text input comes via the ime-frontend
• Graphical output is rendered via the gam

To make your own command, copy the audio.rs template in the apps/repl/src/cmds/ directory, or use this very basic echo template:

use crate::{ShellCmdApi, CommonEnv};
use xous_ipc::String;

#[derive(Debug)]
pub struct Echo {
}

impl<'a> ShellCmdApi<'a> for Echo {
    cmd_api!(echo); // inserts boilerplate for command API

    fn process(&mut self, args: String::<1024>, _env: &mut CommonEnv) -> Result<Option<String::<1024>>, xous::Error> {
        Ok(Some(rest))
    }
}

The "verb" is the name of your command, and it is the argument to the cmd_api!() macro.

process() is your "main" function, and args is a string which contains the rest of the line that was typed into the chat, minus the verb used to identify your command (e.g. the arguments, but not tokenized or parsed in any way). env contains some items in a common environment, for example, connections to the GAM, LLIO server or other resources required by your implementation.

Once you've added your command to the directory, go to the cmds.rs file, and follow the four-step instructions embedded within the file, starting around line 40.