[erlang-questions] stuck at a exercise

[Bengt Kleberg]

You should export functions. In your case b_not/1


bengt

On 01/26/2015 03:09 PM, Roelof Wobben wrote:
> Hello,
>
> At a book im following with self-study I have to do this exercise :
>
> Write a module boolean.erlthat takes logical expressions and Boolean 
> values (represented as the atoms  trueand  false) and returns their 
> Boolean result. The functions
> you write should include b_not/1, b_and/2, b_or/2, and b_nand/2. You 
> should not use
> the logical constructs  and,  or, and  not, but instead use pattern 
> matching to achieve your
> goal.
>
> So I tried the first clause and came with this :
>
> -module(boolean).
>
> -export([boolean/1]).
>
> b_not({true}) ->
>   false.
>
> But as soon as I compile it I see these error messages :
>
> boolean.erl:3: function boolean/1 undefined
> boolean.erl:5: Warning: function b_not/1 is unused
>
> How to solve these ?
>
> Roelof
>
>
>
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