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/* NSC -- new Scala compiler
* Copyright 2005-2011 LAMP/EPFL
* @author Paul Phillips
*/
package scala.tools.nsc
package interpreter
import util.{ BatchSourceFile, Indenter }
import scala.tools.nsc.ast.parser.Tokens._
import java.lang.Integer.toOctalString
/** This began as an attempt at a completely minimal
* pretty printer for a token stream, but as it turns out
* it's "minimal, pretty, scala: pick any two." So
* now it's an unattractive hybrid between minimalism
* and other things. Still, it's a big improvement on the
* way I was printing source in the repl, so in it goes.
*
* @author Paul Phillips
*/
abstract class ReplTokens {
val global: Global
import global._
import syntaxAnalyzer.{ UnitScanner, token2name }
// Mostly, this means print <NL> so we can see where
// semicolon inference took place.
private var rawTokens: Boolean = false
def withRawTokens[T](body: => T): T = {
rawTokens = true
try body
finally rawTokens = false
}
// There's the seed of a good idea in here, but you wouldn't
// know it from the current implementation. The objects are
// trying to depict what feelings of coziness a given token
// might have toward its immediate neighbors. But it lacks
// sufficient granularity and a good resolution mechanism.
sealed abstract class Cozy(l: => Boolean, r: => Boolean) {
def left = l
def right = r
}
object Cozy {
def unapply(x: Cozy) = Some((x.left, x.right))
}
case object |--*--| extends Cozy(false, false)
case object <*--| extends Cozy(true, false)
case object |--*> extends Cozy(false, true)
case object <*> extends Cozy(true, true)
@annotation.switch def escapedChar(ch: Char): String = ch match {
case '\b' => "\\b"
case '\t' => "\\t"
case '\n' => "\\n"
case '\f' => "\\f"
case '\r' => "\\r"
case '"' => "\\\""
case '\'' => "\\\'"
case '\\' => "\\\\"
case _ => String.valueOf(ch)
}
def escape(text: String): String = {
text map { ch =>
if (ch.isControl) "\\0" + toOctalString(ch)
else escapedChar(ch)
} mkString ""
}
private class Arrow(code: Int) {
def ->(str: String): (Int, ReplToken) = (code, Token(code)(str))
def ->(tok: ReplToken): (Int, ReplToken) = (code, tok)
}
private val symbolTokenMap = {
implicit def liftToken(code: Int): Arrow = new Arrow(code)
Map[Int, ReplToken](
AT -> At,
CASECLASS -> "case class",
CASEOBJECT -> "case object",
COLON -> Colon,
COMMA -> Comma,
DOT -> Dot,
EOF -> Eof,
ERROR -> "<error>",
FALSE -> False,
IMPORT -> Import,
LBRACE -> LBrace,
LBRACKET -> LBracket,
LPAREN -> LParen,
NEWLINE -> Newline,
NEWLINES -> Newlines,
NULL -> Null,
RBRACE -> RBrace,
RBRACKET -> RBracket,
RPAREN -> RParen,
SEMI -> Semi,
SUBTYPE -> Subtype,
SUPERTYPE -> Supertype,
TRUE -> True,
VIEWBOUND -> ViewBound/*@XML*/,
XMLSTART -> "<xmlstart>"
/*XML@*/
)
}
def isAlphaId(t: ReplToken) = t match {
case Id(name) => name forall (ch => ch.isDigit || ch.isLetter || ch == '_')
case _ => false
}
def isOperatorId(t: ReplToken) = t match {
case Id(name) => !isAlphaId(t)
case _ => false
}
sealed abstract class ReplToken(val tokenString: String, val cozy: Cozy) {
def this(str: String) = this(str, |--*--| )
def insistsOnSpace = false
def cozyRight(other: ReplToken) = (cozy.right || other.cozy.left)
def cozyLeft(other: ReplToken) = (cozy.left || other.cozy.right)
final def <--?-->(other: ReplToken) = {
!(insistsOnSpace || other.insistsOnSpace) && (
(this cozyRight other) ||
(other cozyLeft this)
)
}
// to show invisibles
def rawString = tokenString
override def toString = (
if (rawTokens) rawString
else tokenString
)
}
trait InsistCozyRight extends ReplToken {
final override def cozyRight(other: ReplToken) = true
}
trait InsistCozyLeft extends ReplToken {
final override def cozyLeft(other: ReplToken) = true
}
trait InsistCozy extends InsistCozyLeft with InsistCozyRight { }
trait InsistSpaced extends ReplToken {
final override def insistsOnSpace = true
}
trait CozyWithLetters extends ReplToken {
override def cozyRight(other: ReplToken) = isAlphaId(other) || super.cozyRight(other)
override def cozyLeft(other: ReplToken) = isAlphaId(other) || super.cozyLeft(other)
}
trait Brackets extends ReplToken {
private def isCozyToken(t: ReplToken) = t == LBracket || t == RBracket || isAlphaId(t)
override def cozyRight(other: ReplToken) = isCozyToken(other) || super.cozyRight(other)
override def cozyLeft(other: ReplToken) = isCozyToken(other) || super.cozyLeft(other)
}
case class Token(value: Int)(str: String) extends ReplToken(str) { }
case class Id(name: String) extends ReplToken(name) { }
case class Lit[T](value: T) extends ReplToken(value match {
case s: String => "\"" + s + "\""
case _ => "" + value
})
case object At extends ReplToken("@") with InsistCozyRight { }
case object Colon extends ReplToken(":", <*--|)
case object Comma extends ReplToken(",", <*--|) with InsistCozyLeft { }
case object Dot extends ReplToken(".", <*>) with InsistCozy { }
case object Eof extends ReplToken("EOF")
case object ErrorToken extends ReplToken("<internal error>")
case object False extends ReplToken("false")
case object Import extends ReplToken("import")
case object LBrace extends ReplToken("{") with InsistSpaced { }
case object LBracket extends ReplToken("[") with Brackets { }
case object LParen extends ReplToken("(", |--*>)
case object Newline extends ReplToken("\n", <*>) with InsistCozy { override def rawString = "<NL>\n" }
case object Newlines extends ReplToken("\n\n", <*>) with InsistCozy { override def rawString = "<NLS>\n\n" }
case object Null extends ReplToken("null")
case object RBrace extends ReplToken("}", |--*>) with InsistSpaced { }
case object RBracket extends ReplToken("]") with Brackets { }
case object RParen extends ReplToken(")", <*--|)
case object Semi extends ReplToken(";", <*--|)
case object Subtype extends ReplToken("<:") with InsistSpaced { }
case object Supertype extends ReplToken(">:") with InsistSpaced { }
case object True extends ReplToken("true")
case object ViewBound extends ReplToken("<%") with InsistSpaced { }
class Tokenizer(in: UnitScanner) {
private def translate(tokenCode: Int): ReplToken = tokenCode match {
case IDENTIFIER | BACKQUOTED_IDENT => Id("" + in.name)
case CHARLIT | INTLIT | LONGLIT => Lit(in.intVal)
case DOUBLELIT | FLOATLIT => Lit(in.floatVal)
case STRINGLIT => Lit(escape(in.strVal))
case SYMBOLLIT => Lit(scala.Symbol(in.strVal))
case _ =>
symbolTokenMap.getOrElse(
tokenCode,
token2name get tokenCode match {
case Some(name) => Token(tokenCode)("" + name)
case _ => Token(tokenCode)("<unknown: " + tokenCode + ">")
}
)
}
def tokenIterator: Iterator[ReplToken] = (
Iterator continually {
try translate(in.token)
finally in.nextToken()
} takeWhile (_ ne Eof)
)
}
def prettyPrintRaw(tokens: TraversableOnce[ReplToken]) {
withRawTokens(prettyPrint(tokens))
}
def prettyPrint(tokens: TraversableOnce[ReplToken]) {
new TokenPrinter prettyPrint tokens
}
private class TokenPrinter {
type TokenTriple = (ReplToken, ReplToken, ReplToken)
val writer = new Indenter
var prev: List[ReplToken] = Nil
def isIdentPart(t: ReplToken) = t match {
case Dot | Id(_) => true
case _ => false
}
def prevNonIdent = prev dropWhile isIdentPart match {
case Nil => ErrorToken
case t :: _ => t
}
def inImport = prevNonIdent == Import
def printToken(left: ReplToken, token: ReplToken) = token match {
case LBrace =>
writer openIndent (
if (writer.atStartOfLine) token
else " " + token
)
case RBrace =>
writer.closeIndent(token)
case tok @ (Newline | Newlines) =>
writer.nextIndent(tok)
case _ =>
writer print (
if (writer.atStartOfLine) token
else if (left <--?--> token) token
else " " + token
)
}
def prettyPrint(tokens: TraversableOnce[ReplToken]) {
val it = Iterator(Newline) ++ tokens.toIterator ++ Iterator(Newline) sliding 3 map { x =>
val List(x1, x2, x3) = x
((x1, x2, x3))
}
prettyPrint(it)
}
def prettyPrint(it: Iterator[TokenTriple]) {
while (it.hasNext) it.next match {
// special casing to avoid newline on empty blocks
case (left, LBrace, RBrace) =>
it.next
writer print " { }"
// special casing to avoid newlines on import x.{ y, z, q }
case (left, LBrace, _) if inImport =>
writer print LBrace
def loop() {
if (it.hasNext) {
val (_, tok, _) = it.next
if (tok != Comma) {
writer print " "
}
writer print tok
if (tok != RBrace)
loop()
}
}
loop()
case (left, token, right) =>
printToken(left, token)
if (it.hasNext) prev ::= token
else printToken(token, right)
}
}
}
}
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