[erlang-questions] distinguish proplists vs. lists of proplists

Richard A. O'Keefe <>
Wed Sep 16 07:15:55 CEST 2015


On 16/09/2015, at 6:26 am, Drew Varner <> wrote:

> A property in a proplist can be an atom or a tuple.

The problem is that the documentation for the proplists
module says that the elements of a proplist can be ANYTHING.

The documentation is a little confusing.  proplists:get_value/[2,3]
only pays attention to pairs; other tuples might as well not be there.

Does anyone know *why* the proplists module is so tolerant of
junk in proplists?  Is it because

get_value(Key, [{Key,Val}|_], _) -> Val;
get_value(Key, [Key|_],       _) -> true;
get_value(Key, [_|Ps],  Default) -> get_value(Key, Ps, Default);
get_value(Key, [],      Default) -> Default.

is the easiest thing to write, or is there a use case for it?




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