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package dotty.tools
package dotc
package printing
import parsing.Tokens._
import scala.annotation.switch
import scala.collection.mutable.StringBuilder
import core.Contexts.Context
/** This object provides functions for syntax highlighting in the REPL */
object SyntaxHighlighting {
implicit class SyntaxFormatting(val sc: StringContext) extends AnyVal {
def hl(args: Any*): String =
sc.s(args.map(x => new String(apply(x.toString).toArray)): _*)
}
val NoColor = Console.RESET
val CommentColor = Console.GREEN
val KeywordColor = Console.CYAN
val LiteralColor = Console.MAGENTA
val TypeColor = Console.GREEN
val AnnotationColor = Console.RED
private def none(str: String) = str
private def keyword(str: String) = KeywordColor + str + NoColor
private def typeDef(str: String) = TypeColor + str + NoColor
private def literal(str: String) = LiteralColor + str + NoColor
private def annotation(str: String) = AnnotationColor + str + NoColor
private val tripleQs = Console.RED_B + "???" + NoColor
private val keywords: Seq[String] = for {
index <- IF to INLINE // All alpha keywords
} yield tokenString(index)
private val interpolationPrefixes =
'A' :: 'B' :: 'C' :: 'D' :: 'E' :: 'F' :: 'G' :: 'H' :: 'I' :: 'J' :: 'K' ::
'L' :: 'M' :: 'N' :: 'O' :: 'P' :: 'Q' :: 'R' :: 'S' :: 'T' :: 'U' :: 'V' ::
'W' :: 'X' :: 'Y' :: 'Z' :: '$' :: '_' :: 'a' :: 'b' :: 'c' :: 'd' :: 'e' ::
'f' :: 'g' :: 'h' :: 'i' :: 'j' :: 'k' :: 'l' :: 'm' :: 'n' :: 'o' :: 'p' ::
'q' :: 'r' :: 's' :: 't' :: 'u' :: 'v' :: 'w' :: 'x' :: 'y' :: 'z' :: Nil
private val typeEnders =
'{' :: '}' :: ')' :: '(' :: '=' :: ' ' :: ',' :: '.' :: '\n' :: Nil
def apply(chars: Iterable[Char]): Iterable[Char] = {
var prev: Char = 0
var remaining = chars.toStream
val newBuf = new StringBuilder
@inline def keywordStart =
prev == 0 || prev == ' ' || prev == '{' || prev == '(' || prev == '\n'
@inline def numberStart(c: Char) =
c.isDigit && (!prev.isLetter || prev == '.' || prev == ' ' || prev == '(' || prev == '\u0000')
def takeChar(): Char = takeChars(1).head
def takeChars(x: Int): Seq[Char] = {
val taken = remaining.take(x)
remaining = remaining.drop(x)
taken
}
while (remaining.nonEmpty) {
val n = takeChar()
if (interpolationPrefixes.contains(n)) {
// Interpolation prefixes are a superset of the keyword start chars
val next = remaining.take(3).mkString
if (next.startsWith("\"")) {
newBuf += n
prev = n
if (remaining.nonEmpty) takeChar() // drop 1 for appendLiteral
appendLiteral('"', next == "\"\"\"")
} else {
if (n.isUpper && keywordStart) {
appendWhile(n, !typeEnders.contains(_), typeDef)
} else if (keywordStart) {
append(n, keywords.contains(_), keyword)
} else {
newBuf += n
prev = n
}
}
} else {
(n: @switch) match {
case '/' =>
if (remaining.nonEmpty) {
remaining.head match {
case '/' =>
takeChar()
eolComment()
case '*' =>
takeChar()
blockComment()
case x =>
newBuf += '/'
}
} else newBuf += '/'
case '=' =>
append('=', _ == "=>", keyword)
case '<' =>
append('<', { x => x == "<-" || x == "<:" || x == "<%" }, keyword)
case '>' =>
append('>', { x => x == ">:" }, keyword)
case '#' =>
if (prev != ' ' && prev != '.') newBuf append keyword("#")
else newBuf += n
prev = '#'
case '@' =>
appendWhile('@', _ != ' ', annotation)
case '\"' =>
appendLiteral('\"', multiline = remaining.take(2).mkString == "\"\"")
case '\'' =>
appendLiteral('\'')
case '`' =>
appendTo('`', _ == '`', none)
case _ => {
if (n == '?' && remaining.take(2).mkString == "??") {
takeChars(2)
newBuf append tripleQs
prev = '?'
} else if (n.isUpper && keywordStart)
appendWhile(n, !typeEnders.contains(_), typeDef)
else if (numberStart(n))
appendWhile(n, { x => x.isDigit || x == '.' || x == '\u0000'}, literal)
else
newBuf += n; prev = n
}
}
}
}
def eolComment() = {
newBuf append (CommentColor + "//")
var curr = '/'
while (curr != '\n' && remaining.nonEmpty) {
curr = takeChar()
newBuf += curr
}
prev = curr
newBuf append NoColor
}
def blockComment() = {
newBuf append (CommentColor + "/*")
var curr = '*'
var open = 1
while (open > 0 && remaining.nonEmpty) {
curr = takeChar()
newBuf += curr
if (curr == '*' && remaining.nonEmpty) {
curr = takeChar()
newBuf += curr
if (curr == '/') open -= 1
} else if (curr == '/' && remaining.nonEmpty) {
curr = takeChar()
newBuf += curr
if (curr == '*') open += 1
}
}
prev = curr
newBuf append NoColor
}
def appendLiteral(delim: Char, multiline: Boolean = false) = {
var curr: Char = 0
var continue = true
var closing = 0
val inInterpolation = interpolationPrefixes.contains(prev)
newBuf append (LiteralColor + delim)
def shouldInterpolate =
inInterpolation && curr == '$' && prev != '$' && remaining.nonEmpty
def interpolate() = {
val next = takeChar()
if (next == '$') {
newBuf += curr
newBuf += next
prev = '$'
} else if (next == '{') {
var open = 1 // keep track of open blocks
newBuf append (KeywordColor + curr)
newBuf += next
while (remaining.nonEmpty && open > 0) {
var c = takeChar()
newBuf += c
if (c == '}') open -= 1
else if (c == '{') open += 1
}
newBuf append LiteralColor
} else {
newBuf append (KeywordColor + curr)
newBuf += next
var c: Char = 'a'
while (c.isLetterOrDigit && remaining.nonEmpty) {
c = takeChar()
if (c != '"') newBuf += c
}
newBuf append LiteralColor
if (c == '"') {
newBuf += c
continue = false
}
}
closing = 0
}
while (continue && remaining.nonEmpty) {
curr = takeChar()
if (curr == '\\' && remaining.nonEmpty) {
val next = takeChar()
newBuf append (KeywordColor + curr)
if (next == 'u') {
val code = "u" + takeChars(4).mkString
newBuf append code
} else newBuf += next
newBuf append LiteralColor
closing = 0
} else if (shouldInterpolate) {
interpolate()
} else if (curr == delim && multiline) {
closing += 1
if (closing == 3) continue = false
newBuf += curr
} else if (curr == delim) {
continue = false
newBuf += curr
} else {
newBuf += curr
closing = 0
}
}
newBuf append NoColor
prev = curr
}
def append(c: Char, shouldHL: String => Boolean, highlight: String => String) = {
var curr: Char = 0
val sb = new StringBuilder(s"$c")
while (remaining.nonEmpty && curr != ' ' && curr != '(' && curr != '\n') {
curr = takeChar()
if (curr != ' ' && curr != '\n') sb += curr
}
val str = sb.toString
val toAdd = if (shouldHL(str)) highlight(str) else str
val suffix = if (curr == ' ' || curr == '\n') s"$curr" else ""
newBuf append (toAdd + suffix)
prev = curr
}
def appendWhile(c: Char, pred: Char => Boolean, highlight: String => String) = {
var curr: Char = 0
val sb = new StringBuilder(s"$c")
while (remaining.nonEmpty && pred(curr)) {
curr = takeChar()
if (pred(curr)) sb += curr
}
val str = sb.toString
val suffix = if (!pred(curr)) s"$curr" else ""
newBuf append (highlight(str) + suffix)
prev = curr
}
def appendTo(c: Char, pred: Char => Boolean, highlight: String => String) = {
var curr: Char = 0
val sb = new StringBuilder(s"$c")
while (remaining.nonEmpty && !pred(curr)) {
curr = takeChar()
sb += curr
}
newBuf append highlight(sb.toString)
prev = curr
}
newBuf.toIterable
}
}
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