xml-lens

Printing

You need to have xml-lens-io included.

To add it to your build add following to your build.sbt:

libraryDependencies += "pl.msitko" %% "xml-lens-io" % xmlLensVersion

Or (in case of scala.js build):

libraryDependencies += "pl.msitko" %%% "xml-lens-io" % xmlLensVersion

The same printing code written in Scala is used for both JVM and JS. Thus, no differences between platforms is expected in terms of printing.

To print XML:

import pl.msitko.xml.entities.{LabeledElement, XmlDocument}
// import pl.msitko.xml.entities.{LabeledElement, XmlDocument}

import pl.msitko.xml.printing.XmlPrinter
// import pl.msitko.xml.printing.XmlPrinter

val document = XmlDocument.noProlog(LabeledElement.unprefixed("root"))
// document: pl.msitko.xml.entities.XmlDocument = XmlDocument(Prolog(None,List(),None),LabeledElement(ResolvedName(,,root),Element(List(),List(),List())))

XmlPrinter.print(document)
// res0: String = <root></root>

Printing configuration

Some behaviors of XmlPrinter.print can be configured with PrinterConfig. It can be passed as implicit parameter. When no implicit config can be found PrinterConfig.Default is used. To find out more about PrinterConfig please read API docs of it.

Printing cookbook

How to print back output which is possibly the most similar to input

There may be situations in which you want to introduce as few formatting changes as possible. In fact default configurations for both parser and printer are well suited for that purpose so the following code will do that:

import pl.msitko.xml.parsing.XmlParser
// import pl.msitko.xml.parsing.XmlParser

import pl.msitko.xml.printing.XmlPrinter
// import pl.msitko.xml.printing.XmlPrinter

// xml formatting is strange here, let us assume we want to keep it
val input = """|<a someAttr="someVal">
               |       <b>someText  </b>
               |<c>otherText</c></a>""".stripMargin
// input: String =
// <a someAttr="someVal">
//        <b>someText  </b>
// <c>otherText</c></a>

XmlParser.parse(input).map { doc =>
  XmlPrinter.print(doc)
}
// res2: scala.util.Either[pl.msitko.xml.parsing.ParsingException,String] =
// Right(<a someAttr="someVal">
//        <b>someText  </b>
// <c>otherText</c></a>)

How to pretty print

import pl.msitko.xml.parsing.XmlParser
// import pl.msitko.xml.parsing.XmlParser

import pl.msitko.xml.printing.{Indent, PrinterConfig, XmlPrinter}
// import pl.msitko.xml.printing.{Indent, PrinterConfig, XmlPrinter}

// xml formatting is strange here, let us assume we want to convert to pretty formatting
val input = """|<a someAttr="someVal">
               |       <b>someText  </b>
               |<c>otherText</c></a>""".stripMargin
// input: String =
// <a someAttr="someVal">
//        <b>someText  </b>
// <c>otherText</c></a>

XmlParser.parse(input).map { doc =>
  implicit val printCfg = PrinterConfig.Default.copy(indent = Indent.IndentWith("  "))
  XmlPrinter.print(doc)
}
// res4: scala.util.Either[pl.msitko.xml.parsing.ParsingException,String] =
// Right(<a someAttr="someVal">
//   <b>someText  </b>
//   <c>otherText</c>
// </a>)

How to print minimized XML

xml-lens takes a little bit unusual approach to minimization and considers it not a property of printing but a transformation performed on document structure (i.e. AST). It does so partially because XML is in theory whitespace sensitive and thus treating whitespaces as printing details does not seem appropriate.

In short to parse XML, minimize it and print it back you need to:

import pl.msitko.xml.printing.XmlPrinter
// import pl.msitko.xml.printing.XmlPrinter

import pl.msitko.xml.printing.XmlPrinter
// import pl.msitko.xml.printing.XmlPrinter

import pl.msitko.xml.dsl._
// import pl.msitko.xml.dsl._

// xml formatting is strange here, let us assume we don't care about it and want to have some minimized output
val input = """|<a someAttr="someVal">
               |       <b>someText  </b>
               |<c>otherText</c></a>""".stripMargin
// input: String =
// <a someAttr="someVal">
//        <b>someText  </b>
// <c>otherText</c></a>

XmlParser.parse(input).map { doc =>
  val minimized = doc.minimize
  XmlPrinter.print(minimized)
}
// res6: scala.util.Either[pl.msitko.xml.parsing.ParsingException,String] = Right(<a someAttr="someVal"><b>someText  </b><c>otherText</c></a>)