rfactor and fix the 5 different (buggy) re-implementations of cmpIgnoreStyle

[timotheecour]

the ones that are actually intended to be case insensitive should be renamed to something else, or cmpIgnoreStyle can get an extra param caseInsensitive = false

links

nim-lang#16391
nim-lang#16392

[ringabout]

I already plan to refactor them and place them in std/private/str*. Use templates so that make cstrutils support JS backend.

[timotheecour]

@xflywind
cool!

Use templates so that make cstrutils support JS backend.

can be discussed in your PR, but here's how to get best of both worlds:

• avoid code bloat (C optimizer is free to either inline or keep as separate proc)
• keep implementation DRY
• works in js, vm, c:

# proc fn[T: openArray[char] or cstring](a: T) = # nim BUG: this doesn't work

template fnImpl(a): untyped =
  # xxx: actual impl goes here
  for ai in a: echo (ai,)

proc fn(a: openArray[char]) = fnImpl(a)
proc fn(a: cstring) = fnImpl(a)
proc fn(a: string) = fnImpl(a)

proc main()=
  fn("abc")
  var b = "abc".cstring
  fn(b)
  fn(['a','b'])

main()
static: main()

[ringabout]

I won't consider VM backend in this PR too much.
I could clean up this in the next PR(cstrutils doesn't support VM currently. It needs more cares to make it work).

[ringabout]

Maybe we also need cmpNimIdentifier.

[ringabout]

• Refactor startsWith and endsWith
• Make cstrutils support VM
• Write more functions to cstrutils
• Add strutils.cmpNimIdentifier