gistfile1.nim

proc c_sprintf(buf, frmt: cstring):int {.header: "<stdio.h>",
  importc: "sprintf", varargs, noSideEffect.}
proc to_s(f: float): string =
  var buf: array [0..64, char]
  var n:int = c_sprintf(buf, "%.16g", f)
  for i in 0..n:
    if buf[i] == '.': return $buf
  buf[n] = '.'
  buf[n+1] = '0'
  buf[n+2] = '\0'
  result = $buf

stdout.writeln(to_s(1))