def get_two_ends(l):
match l:
case [first, *_, last]:
return (first, last)
case [_] | []:
raise ValueError("list is too short to have two ends")
case _:
raise ValueError("not a list")fib 0 = 1
fib 1 = 1
fib n | n >= 2
= fib (n-1) + fib (n-2)def fib(0), do: 1
def fib(1), do: 1
def fib(n) when n >= 2, do: fib(n-1) + fib(n-2)match [head] + tail in [0, 1, 2, 3]:
print(head, tail)match x with
| Some x => println$ x;
| None => println "NONE";
endmatch;This functionality is included in switch statements.// pattern matching on objects, lists, and maps
class Rect(left, top, right, bottom)
fun rect_like_to_rect(v):
match v
| Rect(_, _, _, _): v
| {"LT": [l, t], "RB": [r, b]}: Rect(l, t, r, b)
| {"TL": [t, l], "RB": [b, r]}: Rect(l, t, r, b)
rect_like_to_rect({"TL": [0, 2], "RB": [10, 5]})
// ⇒ Rect(0, 2, 10, 5)
rect_like_to_rect({"LT": [0, 2], "RB": [10, 5]})
// ⇒ Rect(2, 0, 5, 10)
// pattern matching in all binding positions
class Posn(x, y)
fun flip_all([Posn(x, y), ...]):
[Posn(y, x), ...]
flip_all([Posn(1, 2), Posn(3, 4)])
// ⇒ [Posn(2, 1), Posn(4, 3)]
flip_all([Posn(5, 6)])
// ⇒ [Posn(6, 5)]Languages with Pattern Matching include Python, Rust, Haskell, Elixir, Coconut, MoonBit, Felix, Egison, HOPE, Aardvark, Rhombus, NPL
Languages without Pattern Matching include progsbase, Veryl
View all concepts with or missing a hasPatternMatching measurement
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