On Thu, 2010-12-02 at 12:26 -0500, Greg Hendershott wrote:
> Although I've grown accustomed to it, early on I disliked the
> redundancy of define/contract and (my own macro)
> define/contract/provide.
>
> (define/contract (foo x #:y y)
> (int? #:y boolean?)
> ( ... body ... ))
It's interesting to see what other people do.
This is what I have played with. I was interested in adding
documentation to everything, and make it proper quality. Instead of
using comments I want the documentation to have a defined format that
can be exploited, and be part of the language I use with good support. I
don't want to write separate manuals at this point yet.
My style includes function signature, contract, documentation (first
string is brief text, rest strings are separate paragraphs) and a set of
unit tests which also form the set of examples given with the "help". I
haven't included Typed Racket in this but ideally it would be included
too, not just contracts like I have now.
-Markku
---
(define/contract/help (mul lon)
((listof number?) . -> . number?)
("Multiplies a list of numbers"
"The function mul multiplies together the given list of numbers. The
mul of an empty list is 1.")
(((mul '()) -> 1)
((mul '(1)) -> 1)
((mul '(1 2 3 4)) -> 24))
(if (null? lon)
1
(* (first lon)
(mul (rest lon)))))
(define/contract/help (string-shorten s max-length #:replacement
(replacement "..."))
((string? number?) (#:replacement string?). ->* . string?)
("Shortens a string from the right"
"The function string-shorten trims the given string from the right
and replaces extra characters with the given replacement which is ... by
default")
(((string-shorten "word" 4) -> "word")
((string-shorten "word" 2) -> "wo")
((string-shorten "word" 2 #:replacement "x") -> "wx")
((string-shorten "word" 3 #:replacement "x") -> "wox")
((string-shorten "aaabbbcccdddeeefff" 5) -> "aa..."))
(let ((sl (string-length s)))
(if (<= sl max-length)
s
(let* ((rl (string-length replacement))
(leave (- (min sl max-length) rl)))
(if (< leave 0)
(substring s 0 max-length)
(string-append (substring s 0 leave) replacement))))))
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