Thank you for your comment

Beau­tiful Racket / racket school 2019

Day 1

Powerful points

  1. What does this language do?

    #lang pl-checklist-demo
     
     
    1
2
3
    #lang pl-checklist-demo
 
 
    copy to clipboard

  2. What else does it do?

Mission

Make a language called pl-checklist that behaves the same way.

Hint: start by creating a pl-checklist subdi­rec­tory in work, and a blank "main.rkt" module within.

pl-checklist/main.rkt
#lang racket 
 
1
2
#lang racket 
 
copy to clipboard

Does anything happen when you run this test file? Even an error?

pl-checklist/test.rkt
#lang pl-checklist
 
 
1
2
3
#lang pl-checklist
 
 
copy to clipboard

Hint: update your "main.rkt":

pl-checklist/main.rkt
#lang racket
(module+ reader)
1
2
#lang racket
(module+ reader)
copy to clipboard

Does the "test.rkt" result (or error) change?

Hint: sure, it would be great if #lang pl-checklist-lang-maker existed. But we’re here to learn how to do the heavy lifting. Right?

But let’s try it anyhow:

pl-checklist/main.rkt
#lang pl-checklist-lang-maker 
1
#lang pl-checklist-lang-maker
copy to clipboard

What happens when you run "main.rkt"? Does the "test.rkt" result (or error) change?

Summary

There’s a #lang for every­thing.

(Hat tip to the orig­inal check­list by Mc­Millen / Reed / Jones.)

← prev next →