side effects through local() or parse() from times module

[dschaadt]

Hi, I'd like to write a function that extracts the date from a DateTime object 
returns a new DateTime object with that date but time set to 00:00:00. The 
input will be in unixtime due to other requirements. When I use the following
    
    
    func test(unixTime: int64): bool =
      let t1 = local(fromUnix(unixTime))
    #    let t = initDateTime(t1.monthday, t1.month, t1.year, 0, 0, 
0).toTime.toUnix
    
    
    Run

local() leads to side effects. Using instead
    
    
    parse(format(fromUnix(unixTime), "yyyy-MM-dd"), "yyyy-MM-dd").toTime.toUnix
    
    
    Run

also leads to side effects and is slower anyways.

Is there a way to circumvent these side effects such that I can use a func 
instead of proc? Thanks!