Lists and Pattern Matching

• Category: Lists, Tuples and Options
• Description: This sample shows simple uses of lists and functions that pattern match on them.
• Code:

using Nemerle;
using System;
using System.Console;

def data = [1, 2, 3, 4];
WriteLine($"data = $data");
WriteLine($"data.Head = $(data.Head)");
WriteLine($"data.Tail = $(data.Tail)");
WriteLine($"data.Length = $(data.Length)");
    
def consume(data)
{
  | 1 :: rest      => WriteLine("matched a 1"); rest
  | 2 :: 3 :: rest => WriteLine("matched a 2 and 3"); rest 
  | [4]            => WriteLine("matched a 4"); []
  | _              => WriteLine("unexpected!"); [] 
}

def data = consume(data);
def data = consume(data);
def data = consume(data);
WriteLine($"At end of list? $(data is [])")

• Execution Result:

data = [1, 2, 3, 4]
data.Head = 1
data.Tail = [2, 3, 4]
data.Length = 4
matched a 1
matched a 2 and 3
matched a 4
At end of list? True

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