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// NOTE: copy/pasted from scalac with minor patches applied for extensibility required in quasiquotes
// the alternative would be to inherit the existing parser and copy/paste half of it in a random fashion
package org.scalamacros.paradise
package parser
/** This is not a public trait - it contains common code shared
* between the library level XML parser and the compiler's.
* All members should be accessed through those.
*/
trait MarkupParserCommon {
import Utility._
import scala.reflect.internal.Chars.SU
protected def unreachable = scala.sys.error("Cannot be reached.")
type PositionType // Int, Position
type ElementType // NodeSeq, Tree
type NamespaceType // NamespaceBinding, Any
type AttributesType // (MetaData, NamespaceBinding), mutable.Map[String, Tree]
def mkAttributes(name: String, pscope: NamespaceType): AttributesType
def mkProcInstr(position: PositionType, name: String, text: String): ElementType
/** parse a start or empty tag.
* [40] STag ::= '<' Name { S Attribute } [S]
* [44] EmptyElemTag ::= '<' Name { S Attribute } [S]
*/
protected def xTag(pscope: NamespaceType): (String, AttributesType) = {
val name = xName
xSpaceOpt()
(name, mkAttributes(name, pscope))
}
/** '?' {Char})]'?>'
*
* see [15]
*/
def xProcInstr: ElementType = {
val n = xName
xSpaceOpt()
xTakeUntil(mkProcInstr(_, n, _), () => tmppos, "?>")
}
/** attribute value, terminated by either `'` or `"`. value may not contain `<`.
@param endCh either `'` or `"`
*/
def xAttributeValue(endCh: Char): String = {
val buf = new StringBuilder
while (ch != endCh) {
// well-formedness constraint
if (ch == '<') return errorAndResult("'<' not allowed in attrib value", "")
else if (ch == SU) truncatedError("")
else buf append ch_returning_nextch
}
ch_returning_nextch
// @todo: normalize attribute value
buf.toString
}
/** [42] '<' xmlEndTag ::= '<' '/' Name S? '>'
*/
def xEndTag(startName: String) {
xToken('/')
if (xName != startName)
errorNoEnd(startName)
xSpaceOpt()
xToken('>')
}
/** actually, Name ::= (Letter | '_' | ':') (NameChar)* but starting with ':' cannot happen
* Name ::= (Letter | '_') (NameChar)*
*
* see [5] of XML 1.0 specification
*
* pre-condition: ch != ':' // assured by definition of XMLSTART token
* post-condition: name does neither start, nor end in ':'
*/
def xName: String = {
if (ch == SU)
truncatedError("")
else if (!isNameStart(ch))
return errorAndResult("name expected, but char '%s' cannot start a name" format ch, "")
val buf = new StringBuilder
do buf append ch_returning_nextch
while (isNameChar(ch))
if (buf.last == ':') {
reportSyntaxError( "name cannot end in ':'" )
buf.toString dropRight 1
}
else buf.toString
}
/** CharRef ::= "&#" '0'..'9' {'0'..'9'} ";"
* | "&#x" '0'..'9'|'A'..'F'|'a'..'f' { hexdigit } ";"
*
* see [66]
*/
def xCharRef(ch: () => Char, nextch: () => Unit): String =
Utility.parseCharRef(ch, nextch, reportSyntaxError _, truncatedError _)
def xCharRef(it: Iterator[Char]): String = {
var c = it.next()
Utility.parseCharRef(() => c, () => { c = it.next() }, reportSyntaxError _, truncatedError _)
}
def xCharRef: String = xCharRef(() => ch, () => nextch())
/** Create a lookahead reader which does not influence the input */
def lookahead(): BufferedIterator[Char]
/** The library and compiler parsers had the interesting distinction of
* different behavior for nextch (a function for which there are a total
* of two plausible behaviors, so we know the design space was fully
* explored.) One of them returned the value of nextch before the increment
* and one of them the new value. So to unify code we have to at least
* temporarily abstract over the nextchs.
*/
def ch: Char
def nextch(): Unit
protected def ch_returning_nextch: Char
def eof: Boolean
// def handle: HandleType
var tmppos: PositionType
def xHandleError(that: Char, msg: String): Unit
def reportSyntaxError(str: String): Unit
def reportSyntaxError(pos: Int, str: String): Unit
def truncatedError(msg: String): Nothing
def errorNoEnd(tag: String): Nothing
protected def errorAndResult[T](msg: String, x: T): T = {
reportSyntaxError(msg)
x
}
def xToken(that: Char) {
if (ch == that) nextch()
else xHandleError(that, "'%s' expected instead of '%s'".format(that, ch))
}
def xToken(that: Seq[Char]) { that foreach xToken }
/** scan [S] '=' [S]*/
def xEQ() = { xSpaceOpt(); xToken('='); xSpaceOpt() }
/** skip optional space S? */
def xSpaceOpt() = while (isSpace(ch) && !eof) nextch()
/** scan [3] S ::= (#x20 | #x9 | #xD | #xA)+ */
def xSpace() =
if (isSpace(ch)) { nextch(); xSpaceOpt() }
else xHandleError(ch, "whitespace expected")
/** Apply a function and return the passed value */
def returning[T](x: T)(f: T => Unit): T = { f(x); x }
/** Execute body with a variable saved and restored after execution */
def saving[A, B](getter: A, setter: A => Unit)(body: => B): B = {
val saved = getter
try body
finally setter(saved)
}
/** Take characters from input stream until given String "until"
* is seen. Once seen, the accumulated characters are passed
* along with the current Position to the supplied handler function.
*/
protected def xTakeUntil[T](
handler: (PositionType, String) => T,
positioner: () => PositionType,
until: String): T =
{
val sb = new StringBuilder
val head = until.head
val rest = until.tail
while (true) {
if (ch == head && peek(rest))
return handler(positioner(), sb.toString)
else if (ch == SU)
truncatedError("") // throws TruncatedXMLControl in compiler
sb append ch
nextch()
}
unreachable
}
/** Create a non-destructive lookahead reader and see if the head
* of the input would match the given String. If yes, return true
* and drop the entire String from input; if no, return false
* and leave input unchanged.
*/
private def peek(lookingFor: String): Boolean =
(lookahead() take lookingFor.length sameElements lookingFor.iterator) && {
// drop the chars from the real reader (all lookahead + orig)
(0 to lookingFor.length) foreach (_ => nextch())
true
}
}