package mime

import (
	"strings"
)

// isTSpecial reports whether rune is in 'tspecials' as defined by RFC
// 1521 and RFC 2045.
func isTSpecial(r rune) bool {
	return strings.ContainsRune(`()<>@,;:\"/[]?=`, r)
}

// isTokenChar reports whether rune is in 'token' as defined by RFC
// 1521 and RFC 2045.
func isTokenChar(r rune) bool {
	// token := 1*<any (US-ASCII) CHAR except SPACE, CTLs,
	//             or tspecials>

	return c
}

// IsBracket reports whether the rune is a bracket.
func (p Properties) IsBracket() bool { return p.entry&0xF0 != 0 }

// IsOpeningBracket reports whether the rune is an opening bracket.
// IsBracket must return true.
func (p Properties) IsOpeningBracket() bool { return p.entry&openMask != 0 }

// TODO: find a better API and expose.
func (p Properties) reverseBracket(r rune) rune {
	return xorMasks[p.entry>>xorMaskShift] ^ r
}

func _[T ~string](x []rune) T                           { return T(x) }
func _[X ~[]byte, T ~string](x X) T                     { return T(x) }
func _[X ~[]rune, T ~string](x X) T                     { return T(x) }
func _[X Integer | ~[]byte | ~[]rune, T ~string](x X) T { return T(x) }
func _[X Integer | ~[]byte | ~[]rune, T ~*string](x X) T {

	// the closure once per rune.
	prev := ' '
	return Map(
		func(r rune) rune {
			if isSeparator(prev) {
				prev = r
				return unicode.ToTitle(r)
			}
			prev = r
			return r
		},
		s)
}

// TrimLeftFunc returns a slice of the string s with all leading
// Unicode code points c satisfying f(c) removed.
func TrimLeftFunc(s string, f func(rune) bool) string {
	i := indexFunc(s, f, false)

// explicit conversion of string is okay
var _ = []rune("abc")
var _ = []byte("abc")

// implicit is not
var _ []int = "abc"  // ERROR "cannot use|incompatible|invalid|cannot convert"
var _ []byte = "abc" // ERROR "cannot use|incompatible|invalid|cannot convert"

// named string is okay
type Tstring string

var ss Tstring = "abc"
var _ = []rune(ss)
var _ = []byte(ss)

// implicit is still not

Yangmin Zhu <******@****.***> 1617651067 -0700

Poorna <******@****.***> 1716056341 -0700

type M2 interface {
	map[string]int | map[string]float64
}
type M3 interface{ map[string]int | map[rune]int }
type M4[K comparable, V any] interface{ map[K]V | map[rune]V }

func g1[T M1](m T) {
	delete(m, "foo")
}

func g2[T M2](m T) {
	delete(m, "foo")
}

func g3[T M4[rune, V], V any](m T) {
	delete(m, 'k')
}

// make

func m1[
	S1 interface{ []int },

	}
	copy(b, s)
	return b
}

func stringtoslicerune(buf *[tmpStringBufSize]rune, s string) []rune {
	// two passes.
	// unlike slicerunetostring, no race because strings are immutable.
	n := 0
	for range s {
		n++
	}

	var a []rune
	if buf != nil && n <= len(buf) {
		*buf = [tmpStringBufSize]rune{}
		a = buf[:n]
	} else {
		a = rawruneslice(n)
	}

	n = 0

Yangmin Zhu <******@****.***> 1617651067 -0700