a racket meta-language for debugging

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README.md

debug

A lang-extension for debugging, based on sugar/debug from mbutterick/sugar

documentation: http://pkg-build.racket-lang.org/doc/debug/index.html

`#lang debug`

To debug the value of an expression, simply put debug in front of the language at the top of the file (for instance #lang debug racket), and put #R, #RR or #RRR in front of the expression.

#R reports the value and returns it
#RR reports the value with a line number and returns it
#RRR reports the value with the file and line number, and returns it

#lang debug racket
#R(+ 1 2)

Shows the output:

(+ 1 2) = 3
3

#lang debug racket
(+ 1 2 #R(* 3 4))

Shows the output:

(* 3 4) = 12
15

`debug-repl`

> (require debug/repl)
> (define (f x y)
    (debug-repl))
> (f 1 2)
-> ; in the debug-repl now
   x
1
-> y
2
-> (+ x y)
3
-> ; exit the debug-repl by pressing ctrl-D
> ; back in the normal repl
  (f (λ (g a) (g a)) (list add1 4))
-> ; a new debug-repl
   x
#<procedure>
-> y
(list #<procedure:add1> 4)
-> (x string->number "3")
3
-> (x (first y) (second y))
5
-> ; exit this debug-repl by pressing ctrl-D