36 lines
696 B
C#
36 lines
696 B
C#
class lis<a> {}
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abstract class fn <a,b,r> {
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public abstract r apply (a x,b y);
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}
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class fn1<a> : fn <lis<a>,lis<a>,lis<a>>
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{
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public override lis<a> apply (lis<a> x,lis<a> y)
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{
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return M.RevAppend (x,y);
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}
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}
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class M {
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public static b FoldLeft<a, b> (a x, b acc, fn<a, b, b> f)
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{
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return f.apply (x, acc);
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}
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public static lis<a> RevAppend<a> (lis <a> x , lis <a> y) {
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return x;
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}
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public static lis <lis <a>> Concat<a> (lis <lis <a>> l)
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{
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return FoldLeft<lis<lis<a>>, lis<lis<a>>> (l, new lis<lis<a>> (), new
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fn1<lis<a>> ());
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}
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public static void Main ()
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{
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M.Concat (new lis<lis<string>> ());
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}
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}
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