Skip to content
terraform.wiki

Match & Case

match lets a script branch on the shape of a value instead of writing a long chain of if checks.

packet = ["ore", 12]
match packet:
  case ["ore", amount] if amount > 0:
    print("ore", amount)
  case ["ice", amount]:
    print("ice", amount)
  case _:
    print("unknown packet")

Patterns

Section titled “Patterns”
  • Literal patterns: case "ok":, case 0:, case True:, case None:
  • Wildcard: case _:
  • Captures: case amount:
  • Alternatives: case "busy" | "cooling":
  • Guards: case [kind, amount] if amount > 0:
  • List/tuple patterns: case [x, y]:, case [head, *rest]:
  • Dict patterns: case {"status": "ok", "value": value}:

Dict-style patterns also match result objects by field name:

result = self.input.take("iron_ore", 10)
match result:
  case {"status": "ok", "moved": moved}:
    print("moved", moved)
  case {"status": reason, "message": message}:
    warn(reason, message)

Warning

Class patterns such as case Thing(x): are not part of the interpreter. Use list, tuple, dict, literal, and field-name patterns instead.

See also

Section titled “See also”