Would you find its function definition?

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1 
iex(16)> maybe.(:true, :true)
{false, true}
iex(17)> maybe.(:true, :false)
{true, false}
iex(18)> maybe.(:false, :false)
{false, false}
iex(19)> maybe.(:false, :true)
{true, true}
1 Like
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I think I have a 2 clause version for this in my head I will take a closer look into it and tested when I’m at a proper computer and mobile my mobile phone

Yupp, my code does return the expected results.

I want to give others a chance to solve this as well and wait before releasing my solution to the public.

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pattern match the args and return one of the tuples will be considered as a solution or I have to find another interesting solution

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It starts as below:

maybe = &{ ... }
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Nice… I’m far away from that.

edit

My current solution contains an if/2, I’m not happy about it, but I can’t think of another solution right now.

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I have a solution, where the function definition is as short as 12 characters :slight_smile:

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yes, it’s super short

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Mine has 14 characters :frowning: … EDIT: ok, there were two superfluous parentheses, now I am also at 12 :slight_smile:

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SPOILER ALERT – SPOILER ALERT – SPOILER ALERT – SPOILER ALERT
SPOILER ALERT – SPOILER ALERT – SPOILER ALERT – SPOILER ALERT
SPOILER ALERT – SPOILER ALERT – SPOILER ALERT – SPOILER ALERT

Here is the answer:

maybe =  &{ (&1 != &2), (&1 = &2)}

The interesting part is &1 = &2, it is a pattern match not an equality!
in iex you get:

iex(27)> :true = :false
** (MatchError) no match of right hand side value: false

But same as the with special form, when occurs a MatchError, the right hand side value is instead returned, then:

maybe.(:false, :true)
(:false != :true) returns :true
(:false = :true) returns :true

2 Likes
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Actually, instead of &1=&2 you can just use &2 without the pattern match:

maybe = &{&1!=&2, &2}

2 Likes
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Since the args in the problem are boolean, I went for xor for the first element, which makes the solution a bit longer, but more restrictive about the input:

&{:erlang.xor(&1, &2), &2}
6 Likes
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There has been no single correct reply to your question :smiley: my shot of a correct answer is

maybe