Shelp

shelp(sh help) is a library to create a functional and good looking REPL without having to worry about the generic setup and interacting and the terminal. It provides a configurable interface, allowing you to only need to deal with the language specific parts of the REPL.

There are special 2 commands handled by the repl:

• clear - clears the screen
• exit - exits These can be changed with the repl.set_clear_keyword() and repl.set_exit_keyword() respectively. Any other special commands can be handled within the execution loop.

How to use

Take some program that just prints the input back:

use shelp::{Repl, Color};
let repl = Repl::newd("> ", ". ", None);
let mut repl = repl.iter(Color::Green);

// Now 'claer' clears the screen instead of 'clear'.
repl.set_clear_keyword("claer");

for command in repl {
    // Other special commands can be handled here
    if command == "my_special_command" {
        println!("Special command triggered!");
        continue;
    }

    // <Do something>
}

Here no LangInterface is specified, so the default is used. A LangInterface can be specified by implementing the trait and passing it as the generic type argument.

use std::io::{self, prelude::*};
use shelp::{Repl, Color, LangInterface, Result};
// You can use any library, but currently only crossterm is used in the library for terminal.
use crossterm::style::Colorize;

struct MyLangInterface;
// We want to override the linting so numbers are coloured, but we don't have a specific way of
// getting the indentation, so we do not override that.
impl LangInterface for MyLangInterface {
    fn print_line(_: &mut io::Stdout, lines: &[String], index: usize) -> Result<()> {
        // NOTE this is simple linting and has no multi-line context. For more information on
        // the reason all lines are given, see [`LangInterface::print_line`]
        for i in lines[index].chars() {
            if i.is_numeric() {
                print!("{}", i.magenta());
            } else {
                print!("{}", i);
            }
        }
        Ok(())
    }
}

// Use a particular capacity
let mut repl = Repl::<MyLangInterface>::with_capacity("> ", ". ", 128, None);

loop {
    // You can have dynamic colours if you don't use the iterator. It also allows you to use the
    // errors instead of them being ignored.
    // NOTE here it is unwrapped, but it should be dealt with in a better way.
    let command = repl.next(Color::Blue).unwrap();

    // <Do something>
}