def- / nim-iterutils Goto Github PK

import iterutils

iterator take[T](i: Iterable[T], n: Natural): T =
  let i = toIter(i)
  var pos = 0
  for x in i():
    if pos < n:
      yield x
    inc pos

for x in (1..10).take(5): # Output: 1 2 3 4 5
  stdout.write ($x & " ")
echo ""

for x in (1..4).take(5): # number to take is < total iterator members
                         # (should output the whole original iterator: 1 2 3 4)
  stdout.write ($x & " ")
echo ""

for x in (1..10).take(0): # number to take is 0
                          # (should return an empty iterator)
  stdout.write ($x & " ")
echo ""

discard """
for x in (1..10).take(-5): # number to take is negative
                           # (should fail to compile)
  stdout.write ($x & " ")
echo ""
"""

import os, iterutils

# works
for n in concat(toIter(1..4), toIter(20..23)):
  echo n

# does not work
for f in concat(walkDir("."), walkDir(".")):
  echo f

#test.nim

import iterutils
from sequtils import toSeq
import sugar

proc test1()=
  for i in filter(map(filter(2..10, proc(x: int): bool = x mod 2 == 0),
           proc(x: int): int = x * 2), proc(x: int): bool = x mod 8 == 0):
    echo i

  var s = toSeq (2..10).filter(proc(x): bool = x mod 2 == 0).
      map(proc(x): int = x * 2).filter(proc(x): bool = x mod 8 == 0)
  echo s

  var a = (2..10).filter(proc(x: int): bool = x mod 2 == 0)
  var b = a.map((x: int) => x * 2)
  for i in b.map((x: int) => x + 2):
    echo i
test1()