(+ 3 (debug-log (+ 1 2)))
(debug-log 1 2 3) -> 1

debug-log returns the first argument and writes all arguments formatted to standard output. intercept the execution flow for tracing without disturbing it

alternative to (lambda () body ...)

(call-with-values (nullary (partition a? b)) list)

let with simplified form that additionally makes binding just one variable a bit shorter

(let (a 1)
  body ...)

(display-line "test")

(define-syntax-rule (test a b) (+ a b))

(define-syntax-rules test
  ((test a b) (+ a b))
  ((test a) a))

l q qq
lambda quote quasiquote

(map (l (a) (+ a 1)) a)

(map (lambda (a) (+ a 1)) a)

(q a)
(qq a)

(quote a)
(quasiquote a)

(map-integers 10 (l (n) n))

result

(0 1 2 3 4 5 6 7 8 9)

key and value specified alternatingly

(alist "a" 1 (q b) 2)
(ht-create "a" 1 (q b) 2)

in application similar to

(list 1 2 3)
(vector 4 5 6)

-q variants that implicitly quote keys

(alist-q a 1 b 2)
(ht-create-symbol-q a 1 b 2)

; hashtable max-depth -> list:alist
(ht-alist ht)
(ht-alist ht 2)
(ht-alist ht (inf))

(alist-ref x (q a))
(ht-ref x (q a))

-q variants that implicitly quote keys

(alist-ref-q x a)
(ht-ref-q x a)

(alists-ref x 1 2 3)
(ht-tree-ref x 1 2 3)

(define input
  (q
    ("/usr"
      ("share" "guile")
      "include"
      "")))

(prefix-tree->path-list input)

result:

("/usr/share/guile" "/usr/include" "/usr/")