[erlang-questions] How to make this work

[Roelof Wobben]

Correct but my question is how I can access the function with a fun.

Roelof


Op 12-8-2015 om 17:39 schreef Dmitry Kolesnikov:
> Hello,
>
> You can use built-in function
> http://erldocs.com/17.0/stdlib/timer.html?i=0&search=timer:tc#tc/1
>
> You can also check from OTP source the implementation of this function and compare it with your's
> https://github.com/erlang/otp/blob/maint/lib/stdlib/src/timer.erl#L160
>
> It gives you hints :-)
>
> Best Regards,
> Dmitry
>
>> On 12 Aug 2015, at 18:34, Roelof Wobben <r.wobben@REDACTED> 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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