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sdiehl/pattern_match.coffee

Created April 16, 2011 00:35
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Pattern Matching in Coffeescript
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pattern_match.coffee
# Haskell style pattern matching using:
# https://github.com/jfd/match-js/blob/master/match.js
{Match, incl } = require './match.js'
_ = Match.incl
print = console.log
fib = Match(
0, -> 0
1, -> 1
Number, (n) -> fib(n-1)+fib(n-2)
)
head = Match(
Array, ([x,xs...]) -> x
)
tail = Match(
Array, ([x,xs...]) -> xs
)
elem = Match(
[Number, []], (n) -> false
[Number, Array] , (n, [x,xs...]) -> x == n or elem([n,xs])
)
print fib 6
print head [1,2,3]
print tail [1,2,3]
print elem [1,[1,2,3]]
print elem [4,[1,2,3]]
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