Time::Span#*, Time::Span#/ and Float

[nome]

Trying to calculate an estimate of remaining time for a task based on elapsed time and percentage done, using the following code:

done = 0.75 # 75% of work done
elapsed = Time::Span.new(0,1,0)
total = elapsed / done

I see the following error:

Error in line 3: instantiating 'Time::Span#/(Float64)'

in /scr/hallasan/crystal-0.24.0-2/src/time/span.cr:303: no overload matches 'Int64#tdiv' with type Float64
Overloads are:
 - Int#tdiv(other : Int)

    seconds = to_i.tdiv(number)
                   ^~~~

Alternatively:

done = 0.75 # 75% of work done
elapsed = Time::Span.new(0,1,0)
total = elapsed * (1.0/done)

results in

Error in line 3: instantiating 'Time::Span#*(Float64)'

in /scr/hallasan/crystal-0.24.0-2/src/time/span.cr:296: no argument named 'seconds'
Matches are:
 - Time::Span.new(days : Int, hours : Int, minutes : Int, seconds : Int, nanoseconds : Int = 0)
 - Time::Span.new(hours : Int, minutes : Int, seconds : Int)
 - Time::Span.new(*, seconds : Int, nanoseconds : Int)
 - Time::Span.new(*, nanoseconds : Int) (trying this one)

    Span.new(
         ^~~

So, neither Time::Span#/ nor Time::Span#* appear to accept floats. However, the API documentation gives their types as #*(number : Number) and #/(number : Number), and 0.75.is_a? Number # => true.

Am I missing something or is this a bug?

$ crystal -v
Crystal 0.23.0+313 [ea4187c57] (2017-10-27)

LLVM: 3.9.1
Default target: x86_64-unknown-linux-gnu

[petoem]

@nome you are using crystal compiler version 0.23.0+313 with crystal-0.24.0-2 stdlib.
Anyway I don't think this is an issue here.

Both Time::Span#/ and Time::Span#* are bugged.
Time::Span#/ accepts a type Number but tries to use Int#tdiv which only accepts Int not Number and certainly not Float64.

In Time::Span#* on line https://github.com/crystal-lang/crystal/blob/master/src/time/span.cr#L297
it does Int64 * Float64 which results in Float64, hence Time::Span.new fails because there is no named argument called seconds with type Float64.

[petoem]

@nome As a workaround you can use the total_seconds of the elapsed timespan to calculate and then create a new Time::Span from the total with #seconds method.

done = 0.75 # 75% of work done
elapsed = Time::Span.new(0,1,0)
total = elapsed.total_seconds / done
pp total.seconds # => 00:01:20

[akzhan]

/cc @asterite

[nome]

@petoem Thanks, the workaround does help.

(incidentally, I've been using compiler and stdlib from the 0.24.0 pre-release tarball, so I disavow responsibility for any version mismatches ;-))