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Diffstat (limited to 'tests/generics/tgenericvariant.nim')
-rw-r--r-- | tests/generics/tgenericvariant.nim | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/tests/generics/tgenericvariant.nim b/tests/generics/tgenericvariant.nim new file mode 100644 index 000000000..51d01355a --- /dev/null +++ b/tests/generics/tgenericvariant.nim @@ -0,0 +1,23 @@ +type + TMaybe[T] = object + case empty: Bool + of False: value: T + else: nil + +proc Just*[T](val: T): TMaybe[T] = + result.empty = False + result.value = val + +proc Nothing[T](): TMaybe[T] = + result.empty = True + +proc safeReadLine(): TMaybe[string] = + var r = stdin.readLine() + if r == "": return Nothing[string]() + else: return Just(r) + +when isMainModule: + var Test = Just("Test") + echo(Test.value) + var mSomething = safeReadLine() + echo(mSomething.value) |