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fogus/new-style-togetherness.clj

Created August 20, 2010 18:34
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new-style-togetherness.clj
(def sqr #(*% %))
(def csqr (with-constraints sqr
(contract number-cnstr
"constrains the act of squaring"
[n] number? (not= 0 n) => number? pos?))
(csqr 10)
;=> 100
(csqr -10)
;=> 100
(csqr :a)
; java.lang.AssertionError: Assert failed: (number? n)
(csqr 0)
; java.lang.AssertionError: Assert failed: (not= 0 n)
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new-style-trammel.clj
(def sqr #(*% %))
(def csqr (with-constraints sqr
(contract number-cnstr
"constrains squaring to numbers"
[n] number? => number?)
(contract pos-cnstr
"constrains squaring to positives"
[n] (not= 0 n) => pos?)))
(csqr 10)
;=> 100
(csqr -10)
;=> 100
(csqr :a)
; java.lang.AssertionError: Assert failed: (number? n)
(csqr 0)
; java.lang.AssertionError: Assert failed: (not= 0 n)
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fogus commented Aug 20, 2010

See previous version for a different way to do the same thing.

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