scala.meta.internal.tokenizers.LegacyTokenData.scala Maven / Gradle / Ivy

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Scalameta APIs for tokenization and their baseline implementation
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package scala.meta
package internal
package tokenizers

import LegacyToken._
import Chars._
import scala.meta.inputs._

trait LegacyTokenData {
  /** the input that is currently being tokenized */
  var input: Input = null

  /** the next token */
  var token: LegacyToken = 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 offset of the last character of the current token */
  var endOffset: Offset = 0

  /** the name of an identifier */
  var name: String = null

  /** the string value of a literal */
  var strVal: String = null

  /** the base of a number */
  var base: Int = 0

  def copyFrom(td: LegacyTokenData): this.type = {
    this.input = td.input
    this.token = td.token
    this.offset = td.offset
    this.lastOffset = td.lastOffset
    this.endOffset = td.endOffset
    this.name = td.name
    this.strVal = td.strVal
    this.base = td.base
    this
  }

  override def toString = s"{token = $token, position = $offset..$endOffset, lastOffset = $lastOffset, name = $name, strVal = $strVal, base = $base}"

  lazy val reporter: Reporter = Reporter(input)
  import reporter._

  /** Convert current strVal to char value
   */
  def charVal: Char = if (strVal.length > 0) strVal.charAt(0) else 0

  /** Convert current strVal, base to an integer value
   *  This is tricky because of max negative value.
   */
  private def integerVal: BigInt = {
    var input = strVal
    if (input.startsWith("0x") || input.startsWith("0X")) input = input.substring(2)
    if (input.endsWith("l") || input.endsWith("L")) input = input.substring(0, input.length - 1)
    var value: BigInt = 0
    val divider = if (base == 10) 1 else 2
    var i = 0
    val len = input.length
    while (i < len) {
      val d = digit2int(input charAt i, base)
      if (d < 0) {
        syntaxError("malformed integer number", at = offset)
      }
      value = value * base + d
      i += 1
    }
    value
  }

  /** Convert current strVal, base to double value
  */
  private def floatingVal: BigDecimal = {
    def isDeprecatedForm = {
      val idx = strVal indexOf '.'
      (idx == strVal.length - 1) || (
           (idx >= 0)
        && (idx + 1 < strVal.length)
        && (!Character.isDigit(strVal charAt (idx + 1)))
      )
    }
    if (isDeprecatedForm) {
      syntaxError("floating point number is missing digit after dot", at = offset)
    } else {
      val designatorSuffixes = List('d', 'D', 'f', 'F')
      val parsee = if (strVal.nonEmpty && designatorSuffixes.contains(strVal.last)) strVal.dropRight(1) else strVal
      try BigDecimal(parsee)
      catch { case ex: Exception => syntaxError("malformed floating point number", at = offset) }
    }
  }

  def intVal: BigInt = integerVal
  def longVal: BigInt = integerVal
  def floatVal: BigDecimal = floatingVal
  def doubleVal: BigDecimal = floatingVal
}