Deviations: Tuples

Min-size and Pinned Value Tuples


Min-size tuples represent the type of all tuples with a minimum size. There are some functions which will crash if they don't present with a tuple of a desired type. It may also be possible to constrain internal datatypes, as well. See the example below.


the following function

def my_function(tup) when elem(tup, 1) == :foo do

should have signature {any(), :foo, ...} :: :some_result.

note that Dialyzer gives this function the signature tuple() :: :some_result, which does not serve to indicate that tuples of size 0 and 1 will be rejected.


Any tuple with minimum zero should be identical to tuple().

Normalization to erlang tuple types

Any tuple that does not have a fixed size is converted to tuple(). This is a very disappointing loss of information.