Nim/tests/stdlib/tstring.nim

discard """
  targets: "c cpp js"
"""

from std/sequtils import toSeq, map
from std/sugar import `=>`

proc tester[T](x: T) =
  let test = toSeq(0..4).map(i => newSeq[int]())
  doAssert $test == "@[@[], @[], @[], @[], @[]]"

func reverse*(a: string): string =
  result = a
  for i in 0 ..< a.len div 2:
    swap(result[i], result[^(i + 1)])

proc main() =
  block: # ..
    const
      characters = "abcdefghijklmnopqrstuvwxyz"
      numbers = "1234567890"

    # test "slice of length == len(characters)":
    # replace characters completely by numbers
    var s: string
    s = characters
    s[0..^1] = numbers
    doAssert s == numbers

    # test "slice of length > len(numbers)":
    # replace characters by slice of same length
    s = characters
    s[1..16] = numbers
    doAssert s == "a1234567890rstuvwxyz"

    # test "slice of length == len(numbers)":
    # replace characters by slice of same length
    s = characters
    s[1..10] = numbers
    doAssert s == "a1234567890lmnopqrstuvwxyz"

    # test "slice of length < len(numbers)":
    # replace slice of length. and insert remaining chars
    s = characters
    s[1..4] = numbers
    doAssert s == "a1234567890fghijklmnopqrstuvwxyz"

    # test "slice of length == 1":
    # replace first character. and insert remaining 9 chars
    s = characters
    s[1..1] = numbers
    doAssert s == "a1234567890cdefghijklmnopqrstuvwxyz"

    # test "slice of length == 0":
    # insert chars at slice start index
    s = characters
    s[2..1] = numbers
    doAssert s == "ab1234567890cdefghijklmnopqrstuvwxyz"

    # test "slice of negative length":
    # same as slice of zero length
    s = characters
    s[2..0] = numbers
    doAssert s == "ab1234567890cdefghijklmnopqrstuvwxyz"

    when nimvm:
      discard
    else:
      # bug #6223
      doAssertRaises(IndexDefect):
        discard s[0..999]

  block: # ==, cmp
    let world = "hello\0world"
    let earth = "hello\0earth"
    let short = "hello\0"
    let hello = "hello"
    let goodbye = "goodbye"

    doAssert world == world
    doAssert world != earth
    doAssert world != short
    doAssert world != hello
    doAssert world != goodbye

    doAssert cmp(world, world) == 0
    doAssert cmp(world, earth) > 0
    doAssert cmp(world, short) > 0
    doAssert cmp(world, hello) > 0
    doAssert cmp(world, goodbye) > 0

  block: # bug #7816
    tester(1)

  block: # bug #14497, reverse
    doAssert reverse("hello") == "olleh"

  block: # len, high
    var a = "ab\0cd"
    var b = a.cstring
    doAssert a.len == 5
    block: # bug #16405
      when defined(js):
        when nimvm: doAssert b.len == 2
        else: doAssert b.len == 5
      else: doAssert b.len == 2

    doAssert a.high == a.len - 1
    doAssert b.high == b.len - 1

    doAssert "".len == 0
    doAssert "".high == -1
    doAssert "".cstring.len == 0
    doAssert "".cstring.high == -1

    block: # bug #16674
      var c: cstring = nil
      doAssert c.len == 0
      doAssert c.high == -1

static: main()
main()