39 lines
859 B
Tcl
39 lines
859 B
Tcl
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struct Pair(x:Text, y:Text)
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func pairwise(strs:[Text] -> func(->Pair?)):
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i := 1
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return func():
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if i + 1 > strs.length: return none:Pair
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i += 1
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return Pair(strs[i-1], strs[i])?
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func range(first:Int, last:Int -> func(->Int?)):
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i := first
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return func():
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if i > last:
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return none:Int
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i += 1
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return (i-1)?
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func main():
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values := ["A", "B", "C", "D"]
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>> (++: "($(foo.x)$(foo.y))" for foo in pairwise(values))!
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= "(AB)(BC)(CD)"
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>> ["$(foo.x)$(foo.y)" for foo in pairwise(values)]
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= ["AB", "BC", "CD"]
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do:
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result := @[:Text]
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for foo in pairwise(values):
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result:insert("$(foo.x)$(foo.y)")
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>> result[]
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= ["AB", "BC", "CD"]
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>> [i for i in range(5, 10)]
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= [5, 6, 7, 8, 9, 10]
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>> (+: range(5, 10))!
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= 45
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