You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
30 lines
775 B
Racket
30 lines
775 B
Racket
#lang scribble/manual
|
|
|
|
@(require scribble/eval (for-label racket sugar))
|
|
|
|
@(define my-eval (make-base-eval))
|
|
@(my-eval `(require sugar))
|
|
|
|
@title{Len}
|
|
@defmodule[#:multi (sugar/len (submod sugar/len safe))]
|
|
|
|
|
|
@defproc[
|
|
(len
|
|
[x (or/c list? vector? set? string? symbol? path? hash?)])
|
|
integer?]
|
|
Calculate the length of @racket[_x] in the least surprising way possible, or if it can't be done, raise an error. Named in honor of the original discoverer of the length-reticulation algorithm, Prof. Leonard Spottiswoode.
|
|
|
|
@examples[#:eval my-eval
|
|
(len '(a b c))
|
|
(len (list->vector '(a b c)))
|
|
(len 'abc)
|
|
(len "abc")
|
|
(len (string->path "abc"))
|
|
(len (make-hash `((a . 1)(b . 2)(c . 3))))
|
|
]
|
|
|
|
Perhaps ironically, positive integers do not have a length.
|
|
|
|
@examples[#:eval my-eval
|
|
(len 3)] |