Packages

•  package root

  Definition Classes

  root

•  package io

  Definition Classes

  root

•  package dylemma

  Definition Classes

  io

•  package spac

  SPaC (short for "Streaming Parser Combinators") is a library for building stream consumers in a declarative style, specialized for tree-like data types like XML and JSON.

  SPaC (short for "Streaming Parser Combinators") is a library for building stream consumers in a declarative style, specialized for tree-like data types like XML and JSON.

  Many utilities for handling XML and JSON data involve parsing the entire "document" to some DOM model, then inspecting and transforming that model to extract information. The downside to these utilities is that when the document is very large, the DOM may not fit in memory. The workaround for this type of problem is to treat the document as a stream of "events", e.g. "StartElement" and "EndElement" for XML, or "StartObject" and "EndObject" for JSON. The downside to this workaround is that writing code to handle these streams can be complicated and error-prone, especially when the DOM is complicated.

  SPaC's goal is to drastically simplify the process of creating code to handle these streams.

  This package contains the "core" SPaC traits; Parser, Transformer, Splitter, and ContextMatcher.

  See the xml and json subpackages (provided by the xml-spac and json-spac libraries respectively) for specific utilities related to handling XML and JSON event streams.

  Definition Classes

  dylemma

•  package xml

  This package provides extensions to the core "spac" library which allow for the handling of XML data.

  This package provides extensions to the core "spac" library which allow for the handling of XML data.

  Rather than creating explicit classes that extend Parser, Transformer, and Splitter, this package provides type aliases and implicit extensions. For example, XmlParser[A] is just a type alias for Parser[XmlEvent, A], and XmlParser is just a call to Parser[XmlEvent].

  Three main Parser methods are added to Parser[XmlEvent] via the XmlParserApplyOps implicit class:

  • XmlParser.forText - for capturing raw text
  • XmlParser.attr - for capturing mandatory attributes from elements
  • XmlParser.attrOpt - for capturing optional attributes from elements

  One main Splitter constructor method is added to Splitter via the XmlSplitterApplyOps implicit class:

  • Splitter.xml - for creating splitters based on an inspection of an "element stack"

  Three main Splitter member methods are added to Splitter[XmlEvent, C] via the XmlSplitterOps implicit class:

  • .attr - alias for .joinBy(XmlParser.attr(...))
  • .attrOpt - alias for .joinBy(XmlParser.attrOpt(...))
  • .text - alias for .joinBy(XmlParser.forText)

  A DSL for creating xml-specific ContextMatchers is provided to make it more convenient to call Splitter.xml. For example:

  Splitter.xml("things" \ "thing").attr("foo").parseToList

  Can be used to capture a list of the "foo" attributes in the <thing> elements in

  <things>
     <thing foo="hello" />
     <thing foo="Goodbye">
        <extra>junk</extra>
     </thing>
  </thing>

  Definition Classes

  spac

•  object Fs2DataSource

  Provides helpers for creating FS2 streams of io.dylemma.spac.xml.XmlEvent, using fs2-data-xml as the underlying event provider.

  Provides helpers for creating FS2 streams of io.dylemma.spac.xml.XmlEvent, using fs2-data-xml as the underlying event provider.

  Fs2-data is already pretty "plug-and-play", so at best this helper just removes a few steps/pipes that you would have to manually call.

  For example:

  val charStream: Stream[IO, Char] = ???
  
  // this...
  val xmlStream1: Stream[IO, XmlEvent] = {
    import fs2.data.xml._
    charStream
      .through(events)
      .through(namespaceResolver)
      .through(reverenceResolver())
      .through(normalize)
      .through(Fs2DataSource.convert)
  }
  
  // could be replaced with
  val xmlStream2: Stream[IO, XmlEvent] = {
    Fs2DataSource.fromRawXmlStream(charStream)
  }

  Essentially this helper just provides a convenient apply method that accepts String, Stream[F, Char], Stream[F, String], or Stream[F, fs2.data.xml.XmlEvent] to return a Stream[F, XmlEvent] which an XmlParser could then interact with.

  Definition Classes

  xml

• Cleanup
• NoCleanup

io.dylemma.spac.xml.Fs2DataSource

Cleanup

Companion object Cleanup