Easy Spannable on Kotlin

Example.kt

val spanned = spannable{ bold("some") + italic(" formatted") + color(Color.RED, " text") }

val nested = spannable{ bold(italic("nested ")) + url("www.google.com", "text") }

val noWrapping = bold("no ") + sub("wrapping ) + sup("also ") + "works"

text_view.text = spanned + nested + noWrapping

Spannable.kt

import android.text.Spannable
import android.text.SpannableString
import android.text.TextUtils
import android.text.style.*
fun spannable(func: () -> SpannableString) = func()
private fun span(s: CharSequence, o: Any) = (if (s is String) SpannableString(s) else s as? SpannableString
        ?: SpannableString("")).apply { setSpan(o, 0, length, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE) }

operator fun SpannableString.plus(s: SpannableString) = SpannableString(TextUtils.concat(this, s))
operator fun SpannableString.plus(s: String) = SpannableString(TextUtils.concat(this, s))

fun bold(s: CharSequence) = span(s, StyleSpan(android.graphics.Typeface.BOLD))
fun italic(s: CharSequence) = span(s, StyleSpan(android.graphics.Typeface.ITALIC))
fun underline(s: CharSequence) = span(s, UnderlineSpan())
fun strike(s: CharSequence) = span(s, StrikethroughSpan())
fun sup(s: CharSequence) = span(s, SuperscriptSpan())
fun sub(s: CharSequence) = span(s, SubscriptSpan())
fun size(size: Float, s: CharSequence) = span(s, RelativeSizeSpan(size))
fun color(color: Int, s: CharSequence) = span(s, ForegroundColorSpan(color))
fun background(color: Int, s: CharSequence) = span(s, BackgroundColorSpan(color))
fun url(url: String, s: CharSequence) = span(s, URLSpan(url))