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Scanners.scala
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Scanners.scala
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/*
* Scala (https://www.scala-lang.org)
*
* Copyright EPFL and Lightbend, Inc.
*
* Licensed under Apache License 2.0
* (http://www.apache.org/licenses/LICENSE-2.0).
*
* See the NOTICE file distributed with this work for
* additional information regarding copyright ownership.
*/
package scala.tools.nsc
package ast.parser
import scala.tools.nsc.settings.ScalaVersion
import scala.tools.nsc.util.{CharArrayReader, CharArrayReaderData}
import scala.reflect.internal.util._
import scala.reflect.internal.Chars._
import Tokens._
import scala.annotation.{switch, tailrec}
import scala.collection.mutable
import mutable.{ArrayBuffer, ListBuffer}
import scala.tools.nsc.ast.parser.xml.Utility.isNameStart
import java.lang.StringBuilder
import scala.tools.nsc.Reporting.WarningCategory
object Cbuf {
final val TargetCapacity = 256
def create(): StringBuilder = new StringBuilder(TargetCapacity)
implicit class StringBuilderOps(val sb: StringBuilder) extends AnyVal {
def clear(): Unit = {
if (sb.capacity() > TargetCapacity) {
sb.setLength(TargetCapacity)
sb.trimToSize()
}
sb.setLength(0)
}
def toCharArray: Array[Char] = {
val n = sb.length()
val res = new Array[Char](n)
sb.getChars(0, n, res, 0)
res
}
def isEmpty = sb.length() == 0
def last = sb.charAt(sb.length() - 1)
}
}
import Cbuf.StringBuilderOps
/** See Parsers.scala / ParsersCommon for some explanation of ScannersCommon.
*/
trait ScannersCommon {
val global : Global
import global._
/** Offset into source character array */
type Offset = Int
type Token = Int
trait CommonTokenData {
def token: Token
def name: TermName
}
trait ScannerCommon extends CommonTokenData {
/** Consume and discard the next token. */
def nextToken(): Unit
// things to fill in, in addition to buf, decodeUni which come from CharArrayReader
def error(off: Offset, msg: String): Unit
def incompleteInputError(off: Offset, msg: String): Unit
def warning(off: Offset, msg: String, category: WarningCategory): Unit
def deprecationWarning(off: Offset, msg: String, since: String): Unit
// advance past COMMA NEWLINE RBRACE (to whichever token is the matching close bracket)
def skipTrailingComma(right: Token): Boolean = false
}
// Hooks for ScaladocUnitScanner and ScaladocJavaUnitScanner
trait DocScanner {
protected def beginDocComment(prefix: String): Unit = {}
protected def processCommentChar(): Unit = {}
protected def finishDocComment(): Unit = {}
private var lastDoc: DocComment = null
// get last doc comment
def flushDoc(): DocComment = try lastDoc finally lastDoc = null
def registerDocComment(raw: String, pos: Position) = {
lastDoc = DocComment(raw, pos)
signalParsedDocComment(raw, pos)
}
/** To prevent doc comments attached to expressions from leaking out of scope
* onto the next documentable entity, they are discarded upon passing a right
* brace, bracket, or parenthesis.
*/
def discardDocBuffer(): Unit = {}
}
def createKeywordArray(keywords: Seq[(Name, Token)], defaultToken: Token): (Token, Array[Token]) = {
val names = keywords.sortBy(_._1.start).map { case (k, v) => (k.start, v) }
val low = names.head._1
val high = names.last._1
val arr = Array.fill(high - low + 1)(defaultToken)
names foreach { case (k, v) => arr(k + low) = v }
(low, arr)
}
}
trait Scanners extends ScannersCommon {
val global : Global
import global._
trait TokenData extends CommonTokenData {
/** the next token */
var token: Token = EMPTY
/** the offset of the first character of the current token */
var offset: Offset = 0
/** the offset of the character following the token preceding this one */
var lastOffset: Offset = 0
/** the name of an identifier */
var name: TermName = null
/** the string value of a literal */
var strVal: String = null
/** the base of a number */
var base: Int = 0
def copyFrom(td: TokenData): this.type = {
this.token = td.token
this.offset = td.offset
this.lastOffset = td.lastOffset
this.name = td.name
this.strVal = td.strVal
this.base = td.base
this
}
}
/** An interface to most of mutable data in Scanner defined in TokenData
* and CharArrayReader (+ next, prev fields) with copyFrom functionality
* to backup/restore data (used by quasiquotes' lookingAhead).
*/
trait ScannerData extends TokenData with CharArrayReaderData {
/** we need one token lookahead and one token history
*/
val next: TokenData = new TokenData{}
val prev: TokenData = new TokenData{}
def copyFrom(sd: ScannerData): this.type = {
this.next copyFrom sd.next
this.prev copyFrom sd.prev
super[CharArrayReaderData].copyFrom(sd)
super[TokenData].copyFrom(sd)
this
}
}
abstract class Scanner extends CharArrayReader with TokenData with ScannerData with ScannerCommon with DocScanner {
/** A switch whether operators at the start of lines can be infix operators. */
private var allowLeadingInfixOperators = true
private def isDigit(c: Char) = Character.isDigit(c)
import Character.{isHighSurrogate, isLowSurrogate, isUnicodeIdentifierPart, isUnicodeIdentifierStart, isValidCodePoint, toCodePoint}
// given char (ch) is high surrogate followed by low, codepoint passes predicate.
// true means supplementary chars were put to buffer.
// strict to require low surrogate (if not in string literal).
private def isSupplementary(high: Char, test: Int => Boolean, strict: Boolean = true): Boolean =
isHighSurrogate(high) && {
var res = false
val low = lookaheadReader.getc()
if (isLowSurrogate(low)) {
val codePoint = toCodePoint(high, low)
if (isValidCodePoint(codePoint)) {
if (test(codePoint)) {
putChar(high)
putChar(low)
nextChar()
nextChar()
res = true
}
}
else syntaxError(f"illegal character '\\u$high%04x\\u$low%04x'")
}
else if (!strict) {
putChar(high)
nextChar()
res = true
}
else syntaxError(f"illegal character '\\u$high%04x' missing low surrogate")
res
}
private def atSupplementary(ch: Char, f: Int => Boolean): Boolean =
isHighSurrogate(ch) && {
val hi = ch
val r = lookaheadReader
r.nextRawChar()
val lo = r.ch
isLowSurrogate(lo) && {
val codepoint = toCodePoint(hi, lo)
isValidCodePoint(codepoint) && f(codepoint)
}
}
private var openComments = 0
final protected def putCommentChar(): Unit = { processCommentChar(); nextChar() }
@tailrec private def skipLineComment(): Unit = ch match {
case SU | CR | LF =>
case _ => nextChar() ; skipLineComment()
}
private def maybeOpen(): Unit = {
putCommentChar()
if (ch == '*') {
putCommentChar()
openComments += 1
}
}
private def maybeClose(): Boolean = {
putCommentChar()
(ch == '/') && {
putCommentChar()
openComments -= 1
openComments == 0
}
}
@tailrec final def skipNestedComments(): Unit = ch match {
case '/' => maybeOpen() ; skipNestedComments()
case '*' => if (!maybeClose()) skipNestedComments()
case SU => incompleteInputError("unclosed comment")
case _ => putCommentChar() ; skipNestedComments()
}
private def skipToCommentEnd(isLineComment: Boolean): Unit = {
nextChar()
if (isLineComment) skipLineComment()
else {
openComments = 1
val isDocComment = (ch == '*') && { nextChar(); true }
if (isDocComment) {
// Check for the amazing corner case of /**/
if (ch == '/')
nextChar()
else {
beginDocComment("/**")
skipNestedComments()
}
}
else skipNestedComments()
}
}
/** Returns true if a comment was skipped.
* @note Pre-condition: ch == '/'
*/
final def skipComment(): Boolean = ch match {
case '/' | '*' => skipToCommentEnd(isLineComment = ch == '/') ; finishDocComment(); true
case _ => false
}
def isAtEnd = charOffset >= buf.length
def resume(lastCode: Token) = {
token = lastCode
if (next.token != EMPTY && !reporter.hasErrors)
syntaxError("unexpected end of input: possible missing '}' in XML block")
nextToken()
}
/** A character buffer for literals
*/
val cbuf = Cbuf.create()
/** append Unicode character to "cbuf" buffer
*/
protected def putChar(c: Char): Unit = cbuf.append(c)
/** Determines whether this scanner should emit identifier deprecation warnings,
* e.g. when seeing `macro` or `then`, which are planned to become keywords in future versions of Scala.
*/
protected def emitIdentifierDeprecationWarnings = true
/** Clear buffer and set name and token */
private def finishNamed(idtoken: Token = IDENTIFIER): Unit = {
name = newTermName(cbuf.toCharArray)
cbuf.clear()
token = idtoken
if (idtoken == IDENTIFIER) {
val idx = name.start - kwOffset
if (idx >= 0 && idx < kwArray.length) {
token = kwArray(idx)
if (token == IDENTIFIER && allowIdent != name) {
if (name == nme.MACROkw)
syntaxError(s"$name is now a reserved word; usage as an identifier is disallowed")
else if (emitIdentifierDeprecationWarnings)
deprecationWarning(s"$name is a reserved word (since 2.10.0); usage as an identifier is deprecated", "2.10.0")
}
}
}
}
/** Clear buffer and set string */
private def setStrVal(): Unit = {
strVal = cbuf.toString
cbuf.clear()
}
/** a stack of tokens which indicates whether line-ends can be statement separators
* also used for keeping track of nesting levels.
* We keep track of the closing symbol of a region. This can be
* RPAREN if region starts with '('
* RBRACKET if region starts with '['
* RBRACE if region starts with '{'
* ARROW if region starts with 'case'
* STRINGLIT if region is a string interpolation expression starting with '${'
* (the STRINGLIT appears twice in succession on the stack iff the
* expression is a multiline string literal).
*/
var sepRegions: List[Token] = List()
// Get next token ------------------------------------------------------------
/** Are we directly in a string interpolation expression?
*/
private def inStringInterpolation =
sepRegions.nonEmpty && sepRegions.head == STRINGLIT
/** Are we directly in a multiline string interpolation expression?
* @pre inStringInterpolation
*/
private def inMultiLineInterpolation =
inStringInterpolation && sepRegions.tail.nonEmpty && sepRegions.tail.head == STRINGPART
/** Are we in a `${ }` block? such that RBRACE exits back into multiline string. */
private def inMultiLineInterpolatedExpression = {
sepRegions match {
case RBRACE :: STRINGLIT :: STRINGPART :: rest => true
case _ => false
}
}
def lookingAhead[A](body: => A): A = {
val saved = new ScannerData {} copyFrom this
val aLIO = allowLeadingInfixOperators
allowLeadingInfixOperators = false
nextToken()
try body finally {
this copyFrom saved
allowLeadingInfixOperators = aLIO
}
}
/** read next token and return last offset
*/
def skipToken(): Offset = {
val off = offset
nextToken()
off
}
// used by parser to distinguish pattern P(_*, p) from trailing comma.
// EOF is accepted for REPL, which can't look ahead past the current line.
def isTrailingComma(right: Token): Boolean =
token == COMMA && lookingAhead(afterLineEnd() && token == right || token == EOF)
override def skipTrailingComma(right: Token): Boolean =
if (token == COMMA) {
// SIP-27 Trailing Comma (multi-line only) support
// If a comma is followed by a new line & then a closing paren, bracket or brace
// then it is a trailing comma and is ignored
val saved = new ScannerData {} copyFrom this
fetchToken()
(afterLineEnd() && token == right || token == EOF) || { copyFrom(saved) ; false }
} else false
/** Allow an otherwise deprecated ident here */
private var allowIdent: Name = nme.EMPTY
/** Get next token, and allow the otherwise deprecated ident `name` */
def nextTokenAllow(name: Name) = {
val prev = allowIdent
allowIdent = name
try {
nextToken()
} finally {
allowIdent = prev
}
}
// Adapt sepRegions according to last token
def adjustSepRegions(lastToken: Token): Unit = (lastToken: @switch) match {
case LPAREN =>
sepRegions = RPAREN :: sepRegions
case LBRACKET =>
sepRegions = RBRACKET :: sepRegions
case LBRACE =>
sepRegions = RBRACE :: sepRegions
case CASE =>
sepRegions = ARROW :: sepRegions
case RBRACE =>
while (!sepRegions.isEmpty && sepRegions.head != RBRACE)
sepRegions = sepRegions.tail
if (!sepRegions.isEmpty)
sepRegions = sepRegions.tail
discardDocBuffer()
case RBRACKET | RPAREN =>
if (!sepRegions.isEmpty && sepRegions.head == lastToken)
sepRegions = sepRegions.tail
discardDocBuffer()
case ARROW =>
if (!sepRegions.isEmpty && sepRegions.head == lastToken)
sepRegions = sepRegions.tail
case STRINGLIT =>
if (inMultiLineInterpolation)
sepRegions = sepRegions.tail.tail
else if (inStringInterpolation)
sepRegions = sepRegions.tail
case _ =>
}
/** Advance beyond a case token without marking the CASE in sepRegions.
* This method should be called to skip beyond CASE tokens that are
* not part of matches, i.e. no ARROW is expected after them.
*/
def skipCASE(): Unit = {
assert(token == CASE, s"Internal error: skipCASE() called on non-case token $token")
nextToken()
sepRegions = sepRegions.tail
}
/** True to warn about migration change in infix syntax. */
private val infixMigration = settings.Xmigration.value <= ScalaVersion("2.13.2")
/** Produce next token, filling TokenData fields of Scanner.
*/
def nextToken(): Unit = {
val lastToken = token
adjustSepRegions(lastToken)
// Read a token or copy it from `next` tokenData
if (next.token == EMPTY) {
lastOffset = charOffset - 1
if (lastOffset > 0 && buf(lastOffset) == '\n' && buf(lastOffset - 1) == '\r') {
lastOffset -= 1
}
if (inStringInterpolation) fetchStringPart() else fetchToken()
if (token == ERROR) {
if (inMultiLineInterpolation)
sepRegions = sepRegions.tail.tail
else if (inStringInterpolation)
sepRegions = sepRegions.tail
}
} else {
this copyFrom next
next.token = EMPTY
}
def isSimpleExprIntroToken(token: Token): Boolean = token match {
case CHARLIT | INTLIT | LONGLIT | FLOATLIT | DOUBLELIT |
STRINGLIT | INTERPOLATIONID | SYMBOLLIT | TRUE | FALSE | NULL | // literals
IDENTIFIER | BACKQUOTED_IDENT | THIS | SUPER | NEW | USCORE |
LPAREN | LBRACE | XMLSTART => true
case _ => false
}
def insertNL(nl: Token): Unit = {
next.copyFrom(this)
// todo: make offset line-end of previous line?
offset = if (lineStartOffset <= offset) lineStartOffset else lastLineStartOffset
token = nl
}
def isOperator: Boolean = token == BACKQUOTED_IDENT || token == IDENTIFIER && isOperatorPart(name.charAt(name.length - 1))
/* A leading infix operator must be followed by a lexically suitable expression.
* Usually any simple expr will do. However, a backquoted identifier may serve as
* either an op or a reference. So the additional constraint is that the following
* token can't be an assignment operator. (Dotty disallows binary ops, hence the
* test for unary.) See run/multiLineOps.scala for 42 + `x` on 3 lines, where +
* is not leading infix because backquoted x is non-unary op.
*/
def followedByInfixRHS: Boolean = {
//def isCandidateInfixRHS: Boolean = isSimpleExprIntroToken(token) && (!isOperator || nme.raw.isUnary(name) || token == BACKQUOTED_IDENT)
def isAssignmentOperator: Boolean =
name.endsWith('=') && !name.startsWith('=') && isOperatorPart(name.startChar) &&
(name.length != 2 || (name.startChar match { case '!' | '<' | '>' => false case _ => true }))
def isCandidateInfixRHS: Boolean = isSimpleExprIntroToken(token) && (!isOperator || token == BACKQUOTED_IDENT || !isAssignmentOperator)
lookingAhead {
isCandidateInfixRHS || token == NEWLINE && { nextToken() ; isCandidateInfixRHS }
}
}
/* A leading symbolic or backquoted identifier is treated as an infix operator
* if it is followed by at least one ' ' and a token on the same line
* that can start an expression.
*/
def isLeadingInfixOperator =
allowLeadingInfixOperators &&
isOperator &&
(isWhitespace(ch) || ch == LF) &&
followedByInfixRHS
/* Insert NEWLINE or NEWLINES if
* - we are after a newline
* - we are within a { ... } or on toplevel (wrt sepRegions)
* - the current token can start a statement and the one before can end it
* insert NEWLINES if we are past a blank line, NEWLINE otherwise
*/
if (!applyBracePatch() && afterLineEnd() && inLastOfStat(lastToken) && inFirstOfStat(token) &&
(sepRegions.isEmpty || sepRegions.head == RBRACE)) {
if (pastBlankLine()) insertNL(NEWLINES)
else if (!isLeadingInfixOperator) insertNL(NEWLINE)
else if (!currentRun.isScala3) {
val msg = """|Line starts with an operator that in future
|will be taken as an infix expression continued from the previous line.
|To force the previous interpretation as a separate statement,
|add an explicit `;`, add an empty line, or remove spaces after the operator."""
if (infixMigration) deprecationWarning(msg.stripMargin, "2.13.2")
insertNL(NEWLINE)
}
}
postProcessToken()
// print("["+this+"]")
} // end nextToken
// Join CASE + CLASS => CASECLASS, CASE + OBJECT => CASEOBJECT, SEMI + ELSE => ELSE
def postProcessToken(): Unit =
if (token == CASE) {
prev copyFrom this
val nextLastOffset = charOffset - 1
fetchToken()
def resetOffset(): Unit = {
offset = prev.offset
lastOffset = prev.lastOffset
}
if (token == CLASS) {
token = CASECLASS
resetOffset()
} else if (token == OBJECT) {
token = CASEOBJECT
resetOffset()
} else {
lastOffset = nextLastOffset
next copyFrom this
this copyFrom prev
}
} else if (token == SEMI) {
prev copyFrom this
fetchToken()
if (token != ELSE) {
next copyFrom this
this copyFrom prev
}
}
/** Is current token first one after a newline? */
private def afterLineEnd(): Boolean =
lastOffset < lineStartOffset &&
(lineStartOffset <= offset ||
lastOffset < lastLineStartOffset && lastLineStartOffset <= offset)
/** Is there a blank line between the current token and the last one?
* @pre afterLineEnd().
*/
private def pastBlankLine(): Boolean = {
var idx = lastOffset
var ch = buf(idx)
val end = offset
while (idx < end) {
if (ch == LF || ch == FF) {
do {
idx += 1; ch = buf(idx)
if (ch == LF || ch == FF) {
// println("blank line found at "+lastOffset+":"+(lastOffset to idx).map(buf(_)).toList)
return true
}
if (idx == end) return false
} while (ch <= ' ')
}
idx += 1; ch = buf(idx)
}
false
}
/** read next token, filling TokenData fields of Scanner.
*/
@tailrec
protected final def fetchToken(): Unit = {
offset = charOffset - 1
(ch: @switch) match {
case ' ' | '\t' | CR | LF | FF =>
nextChar()
fetchToken()
case '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' | // scala-mode: need to understand multi-line case patterns
'z' =>
putChar(ch)
nextChar()
getIdentRest()
if (ch == '"' && token == IDENTIFIER) token = INTERPOLATIONID
case '<' => // is XMLSTART?
def fetchLT() = {
val last = if (charOffset >= 2) buf(charOffset - 2) else ' '
nextChar()
last match {
case ' ' | '\t' | '\n' | '{' | '(' | '>' if isNameStart(ch) || ch == '!' || ch == '?' =>
token = XMLSTART
case _ =>
// Console.println("found '<', but last is '"+in.last+"'"); // DEBUG
putChar('<')
getOperatorRest()
}
}
fetchLT()
case '~' | '!' | '@' | '#' | '%' |
'^' | '*' | '+' | '-' | /*'<' | */
'>' | '?' | ':' | '=' | '&' |
'|' | '\\' =>
putChar(ch)
nextChar()
getOperatorRest()
case '/' =>
nextChar()
if (skipComment()) {
fetchToken()
} else {
putChar('/')
getOperatorRest()
}
case '0' =>
def fetchLeadingZero(): Unit = {
nextChar()
ch match {
case 'x' | 'X' => base = 16 ; nextChar()
//case 'b' | 'B' => base = 2 ; nextChar()
case _ => base = 10 ; putChar('0')
}
if (base != 10 && !isNumberSeparator(ch) && digit2int(ch, base) < 0)
syntaxError("invalid literal number")
}
fetchLeadingZero()
getNumber()
case '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' =>
base = 10
getNumber()
case '`' =>
getBackquotedIdent()
case '\"' =>
def fetchDoubleQuote() = {
if (token == INTERPOLATIONID) {
nextRawChar()
if (ch == '\"') {
val lookahead = lookaheadReader
lookahead.nextChar()
if (lookahead.ch == '\"') {
nextRawChar() // now eat it
offset += 3
nextRawChar()
getStringPart(multiLine = true)
sepRegions = STRINGPART :: sepRegions // indicate string part
sepRegions = STRINGLIT :: sepRegions // once more to indicate multi line string part
} else {
nextChar()
token = STRINGLIT
strVal = ""
}
} else {
offset += 1
getStringPart(multiLine = false)
sepRegions = STRINGLIT :: sepRegions // indicate single line string part
}
} else {
nextChar()
if (ch == '\"') {
nextChar()
if (ch == '\"') {
nextRawChar()
getRawStringLit()
} else {
token = STRINGLIT
strVal = ""
}
} else {
getStringLit()
}
}
}
fetchDoubleQuote()
case '\'' =>
def unclosedCharLit() = {
val unclosed = "unclosed character literal"
// advise if previous token was Symbol contiguous with the orphan single quote at offset
val msg = {
val maybeMistakenQuote =
this match {
case sfs: SourceFileScanner =>
val wholeLine = sfs.source.lineToString(sfs.source.offsetToLine(offset))
wholeLine.count(_ == '\'') > 1
case _ => false
}
if (token == SYMBOLLIT && offset == lastOffset) s"""$unclosed (or use " for string literal "$strVal")"""
else if (maybeMistakenQuote) s"""$unclosed (or use " not ' for string literal)"""
else unclosed
}
syntaxError(msg)
}
/** Either at closing quote of charlit
* or run the op and take it as a (deprecated) Symbol identifier.
*/
def charLitOrSymbolAfter(op: () => Unit): Unit =
if (ch == '\'') {
nextChar()
token = CHARLIT
setStrVal()
} else {
op()
token = SYMBOLLIT
strVal = name.toString
}
def fetchSingleQuote() = {
nextChar()
if (isIdentifierStart(ch)) {
putChar(ch)
nextChar()
charLitOrSymbolAfter(() => getIdentRest())
}
else if (isOperatorPart(ch) && (ch != '\\')) {
putChar(ch)
nextChar()
charLitOrSymbolAfter(() => getOperatorRest())
}
else if (!isAtEnd && (ch != SU && ch != CR && ch != LF)) {
val isEmptyCharLit = (ch == '\'')
getLitChar()
if (ch == '\'') {
if (isEmptyCharLit)
syntaxError("empty character literal (use '\\'' for single quote)")
else {
nextChar()
if (cbuf.length != 1)
syntaxError("illegal codepoint in Char constant: " + cbuf.toString.map(c => f"\\u$c%04x").mkString("'", "", "'"))
else {
token = CHARLIT
setStrVal()
}
}
}
else if (isEmptyCharLit)
syntaxError("empty character literal")
else
unclosedCharLit()
}
else unclosedCharLit()
}
fetchSingleQuote()
case '.' =>
nextChar()
if ('0' <= ch && ch <= '9') {
putChar('.'); getFraction()
} else {
token = DOT
}
case ';' =>
nextChar(); token = SEMI
case ',' =>
nextChar(); token = COMMA
case '(' =>
nextChar(); token = LPAREN
case '{' =>
nextChar(); token = LBRACE
case ')' =>
nextChar(); token = RPAREN
case '}' =>
if (inMultiLineInterpolatedExpression) nextRawChar() else nextChar()
token = RBRACE
case '[' =>
nextChar(); token = LBRACKET
case ']' =>
nextChar(); token = RBRACKET
case SU =>
if (isAtEnd) {
bidiChars.foreach { case (char, offset) =>
syntaxError(offset, f"found unicode bidirectional character '\\u$char%04x'; in a string or character literal, use a unicode escape instead")
}
token = EOF
}
else {
syntaxError("illegal character")
nextChar()
}
case _ =>
def fetchOther() = {
if (ch == '\u21D2') {
deprecationWarning("The unicode arrow `⇒` is deprecated, use `=>` instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.", "2.13.0")
nextChar(); token = ARROW
} else if (ch == '\u2190') {
deprecationWarning("The unicode arrow `←` is deprecated, use `<-` instead. If you still wish to display it as one character, consider using a font with programming ligatures such as Fira Code.", "2.13.0")
nextChar(); token = LARROW
} else if (isUnicodeIdentifierStart(ch)) {
putChar(ch)
nextChar()
getIdentRest()
if (ch == '"' && token == IDENTIFIER) token = INTERPOLATIONID
} else if (isSpecial(ch)) {
putChar(ch)
nextChar()
getOperatorRest()
} else if (isSupplementary(ch, isUnicodeIdentifierStart)) {
getIdentRest()
if (ch == '"' && token == IDENTIFIER) token = INTERPOLATIONID
} else if (isSupplementary(ch, isSpecial)) {
getOperatorRest()
} else {
syntaxError(f"illegal character '\\u$ch%04x'")
nextChar()
}
}
fetchOther()
}
}
/** Can token start a statement? */
def inFirstOfStat(token: Token) = token match {
case EOF | CATCH | ELSE | EXTENDS | FINALLY | FORSOME | MATCH | WITH | YIELD |
COMMA | SEMI | NEWLINE | NEWLINES | DOT | COLON | EQUALS | ARROW | LARROW |
SUBTYPE | VIEWBOUND | SUPERTYPE | HASH | RPAREN | RBRACKET | RBRACE | LBRACKET =>
false
case _ =>
true
}
/** Can token end a statement? */
def inLastOfStat(token: Token) = token match {
case CHARLIT | INTLIT | LONGLIT | FLOATLIT | DOUBLELIT | STRINGLIT | SYMBOLLIT |
IDENTIFIER | BACKQUOTED_IDENT | THIS | NULL | TRUE | FALSE | RETURN | USCORE |
TYPE | XMLSTART | RPAREN | RBRACKET | RBRACE =>
true
case _ =>
false
}
// Identifiers ---------------------------------------------------------------
private def getBackquotedIdent(): Unit = {
nextChar()
getLitChars('`')
if (ch == '`') {
nextChar()
finishNamed(BACKQUOTED_IDENT)
if (name.length == 0) syntaxError("empty quoted identifier")
}
else syntaxError("unclosed quoted identifier")
}
@tailrec
private def getIdentRest(): Unit = (ch: @switch) match {
case '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' | '$' |
'a' | 'b' | 'c' | 'd' | 'e' |
'f' | 'g' | 'h' | 'i' | 'j' |
'k' | 'l' | 'm' | 'n' | 'o' |
'p' | 'q' | 'r' | 's' | 't' |
'u' | 'v' | 'w' | 'x' | 'y' |
'z' |
'0' | '1' | '2' | '3' | '4' |
'5' | '6' | '7' | '8' | '9' =>
putChar(ch)
nextChar()
getIdentRest()
case '_' =>
putChar(ch)
nextChar()
getIdentOrOperatorRest()
case ' ' | LF | // optimize for common whitespace
SU => // strangely enough, Character.isUnicodeIdentifierPart(SU) returns true!
finishNamed()
case _ =>
if (isUnicodeIdentifierPart(ch)) {
putChar(ch)
nextChar()
getIdentRest()
}
else if (isSupplementary(ch, isUnicodeIdentifierPart))
getIdentRest()
else
finishNamed()
}
@tailrec
private def getOperatorRest(): Unit = (ch: @switch) match {
case ' ' | LF => finishNamed() // optimize
case '~' | '!' | '@' | '#' | '%' |
'^' | '*' | '+' | '-' | '<' |
'>' | '?' | ':' | '=' | '&' |
'|' | '\\' =>
putChar(ch); nextChar(); getOperatorRest()
case '/' =>
nextChar()
if (skipComment()) finishNamed()
else { putChar('/'); getOperatorRest() }
case _ =>
if (isSpecial(ch)) { putChar(ch); nextChar(); getOperatorRest() }
else if (isSupplementary(ch, isSpecial)) getOperatorRest()
else finishNamed()
}
private def getIdentOrOperatorRest(): Unit =
if (isIdentifierPart(ch) || isSupplementary(ch, isIdentifierPart)) getIdentRest() else getOperatorRest()
// Literals -----------------------------------------------------------------
private def getStringLit() = {
getLitChars('"')
if (ch == '"') {
setStrVal()
nextChar()
token = STRINGLIT
} else unclosedStringLit()
}
private def unclosedStringLit(seenEscapedQuoteInInterpolation: Boolean = false): Unit = {
val note =
if (seenEscapedQuoteInInterpolation) "; note that `\\\"` no longer closes single-quoted interpolated string literals since 2.13.6, you can use a triple-quoted string instead"
else ""
syntaxError(s"unclosed string literal$note")
}
private def replaceUnicodeEscapesInTriple(): Unit =
if(strVal != null) {
try {
val replaced = StringContext.processUnicode(strVal)
if(replaced != strVal) {
val diffPosition = replaced.zip(strVal).zipWithIndex.collectFirst{ case ((r, o), i) if r != o => i}.getOrElse(replaced.length - 1)
deprecationWarning(offset + 3 + diffPosition, "Unicode escapes in triple quoted strings are deprecated, use the literal character instead", since="2.13.2")
}
strVal = replaced
} catch {
case ue: StringContext.InvalidUnicodeEscapeException => {
syntaxError(offset + 3 + ue.index, ue.getMessage())
}
}
}
@tailrec private def getRawStringLit(): Unit = {
if (ch == '\"') {
nextRawChar()
if (isTripleQuote()) {
setStrVal()
if(!currentRun.isScala3) replaceUnicodeEscapesInTriple()
token = STRINGLIT
} else
getRawStringLit()
} else if (ch == SU) {
incompleteInputError("unclosed multi-line string literal")
} else {
putChar(ch)
nextRawChar()
getRawStringLit()
}
}
// for interpolated strings
@tailrec private def getStringPart(multiLine: Boolean, seenEscapedQuote: Boolean = false): Unit = {
def finishStringPart() = {
setStrVal()
token = STRINGPART
next.lastOffset = charOffset - 1
next.offset = charOffset - 1