What's Next

Congratulations — you have completed the Run language tour! Here is a summary of what you learned and where to go from here.

What you covered

• Basics — variables, constants, types, functions, operators
• Control flow — for loops, if/else, switch, break/continue, defer
• Data types — structs, slices, maps, strings, pointers
• Type system — methods, interfaces, sum types, nullable types, newtypes
• Error handling — error unions with !T and bare !, try, and switch
• Closures — first-class functions and captured variables
• Concurrency — green threads with run, channels for communication
• Memory model — generational references, owning and non-owning pointers
• Tooling — testing, project structure, standard library

A complete example

Here is a small program that ties several concepts together:

package main

use "fmt"
use "os"

pub type Display interface {
    fun string() string
}

pub type Config struct {
    implements (Display)

    host: string
    port: int
}

fun (c @Config) string() string {
    return fmt.sprintf("%s:%d", c.host, c.port)
}

fun load_config(path: string) !Config {
    content := try os.readFile(path)
    host := try parse_field(content, "host")
    port := try parseInt(try parse_field(content, "port"))
    return Config{ host: host, port: port }
}

pub fun main() {
    switch load_config("server.conf") {
        .ok(config) :: {
            fmt.println("starting server on", config.string())
        },
        .err(e) :: {
            fmt.println("error:", e)
            os.exit(1)
        },
    }
}

Next steps

• Read the specification — the full language spec covers every detail
• Build something — the best way to learn is to write a real program
• Explore the standard library — fmt, http, json, and more are ready to use
• Join the community — ask questions, share what you build, and help improve Run

Happy coding!