DrRacket indentation issue

Questions & Answers
1

Hello,

I've created an alias for lambda:

(define-syntax procedure
  (syntax-rules ()
    [(procedure (arg ...) expr1 expr ...)
     (lambda (arg ...) expr1 expr ...)]))

but, when I use it, the indentation changes:

(lambda (x y)
  (+ x y))

(procedure (x y)
           (+ x y))

Is there a way to fix this?
Probably if there's a way it's in the documentation, but I don't know where to look.

Thank you
Matteo

2

Yes. Use the settings in DrRacket.

https://docs.racket-lang.org/drracket/prefs-explanation.html#(part._.Editing)

1 Like
3

| matteo-daddio
March 11 |

  • | - |

Hello,

I've created an alias for lambda:

(define-syntax procedure
  (syntax-rules ()
    [(procedure (arg ...) expr1 expr ...)
     (lambda (arg ...) expr1 expr ...)]))

BTW, if you only want to change the name without changing anything else, a better definition would be

(define-syntax procedure
(syntax-rules ()
((_ args expr1 expr ...)
(lambda args expr1 expr ...))))

Your version:

((procedure x x) 1 2 3)
Exception: invalid syntax (procedure x x)

This version:

((procedure x x) 1 2 3)
(1 2 3)

1 Like
4

There's also make-rename-transformer

5

I was thinking there should be a way to tell how to indent a syntax when it’s defined.
For example, something like this:

(define-syntax procedure
  #:indent-like ‘lambda
  (syntax-rules ()
    [(procedure args expr1 expr ...)
     (lambda args expr1 expr ...)]))

What do you think?

Matteo

6

@rfindler is working on such an extension.

2 Likes