[erlang-questions] How to make this work

[Garry Hodgson]

read the documentation on the proper syntax for defining funs.

On 8/12/15 11:34 AM, Roelof Wobben wrote:
> Hello,
>
> Im trying this exercise from the programming erlang book.
>
> Look up the definitions of erlang:now/0, erlang:date/0, and 
> erlang:time/0. Write a
> function called my_time_func(F), which evaluates the fun F and times how
> long it takes.
>
> So I did this :
>
> -module(my_time).
>
> -export( [time_spend/1] ).
>
> time_spend(F) ->
>     Begintime = time:now(),
>     F(3),
>     Endtime = time:now(),
>     Endtime - Begintime.
>
>
> but then when I do this in erl :
>
> 11> my_time:time_spend(fun x -> 2 * X end).
>  * 1: syntax error before: '->'
> 11> my_time:time_spend(Double = fun x -> 2 * X end).
> * 1: syntax error before: '->'
>
> how can I make this work ?
>
> Roelof
>
>
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