XSequence

Xml parser/writer for Wren

Api similar to C#'s XLinq

To use, download the latest release and take the single file xsequence.wren and put it into your project

Documentation

Quick Examples

To create an xml document like this:

<?xml version="1.0" encoding="utf-8"?>
<fishies amount="2">
  <!--This is a comment in an element-->
  <danio name="zebra" color="red"/>
  <danio name="pearl" color="pink"/>
  <danio>value</danio>
</fishies>
<!--This is a comment in a document-->

You can write code like this to build the tree

import "./xsequence" for XDocument, XElement, XAttribute, XComment

var doc = XDocument.new(
    XElement.new("fishies",
        XComment.new("This is a comment in an element"),
        XAttribute.new("amount", 2),
        XElement.new("danio",
            XAttribute.new("name", "zebra"),
            XAttribute.new("color", "red")
        ),
        XElement.new("danio",
            XAttribute.new("name", "pearl"),
            XAttribute.new("color", "pink")
        ),
        XElement.new("danio", "value")
    ),
    XComment.new("This is a comment in a document")
)

Then to save to a string you can either do

var string = doc.toString

Or for better performance if you are able to write directly to a file stream, you can hook in a custom writer function

doc.write {|s|
  stream.writeString(s)
}

To parse xml document, you first load the xml into a string, then parse it with XDocument. In wren_cli you could do something like this

var xmlText = File.read("myDocument.xml")
var doc = XDocument.parse(xmlText)

If we have a document loaded which is like the fishies document shown above, you could navigate the names of all fishies which are pink

var colorOfFishCalledPearl = doc
    .elementOrAbort("fishies")
    .elements("danio")
    .where {|e| e.attributeValue("color") == "pink" }
    .map {|e| e.attributeValue("name") }
    .toList

You can get the values converted to number, or boolean too. In the following example we get the fish called pearl, then get it's size converted to a Num. If there is no "size" attribute, then it uses the default value provided 2. This converter funcionality is extensible, see the "collada" example.

var pearlTheFish = doc.elementOrAbort("fishies").findElement("danio") {|e| e.attributeValue("name") == "pearl" }
var sizeOfPearl = pearlTheFish.attributeValue("size", Num, 2)

The library also supports namespaces like so

var element = XElement.parse("<p:svg xmlns:p='http://www.w3.org/2000/svg'/>")
// will load into an element identical to
element = XElement.new("{http://www.w3.org/2000/svg}svg", XAttribute.xmlns("p", "http://www.w3.org/2000/svg"))
// the namespace prefix is replaced with the value itself delimited by curly braces

Testing

Using wren-assert for generic assertions.

To run tests use wren cli

> wren_cli.exe test.wren

If you're using vscode you can use the automated task

The exceptions are caught by default, which loses the call stack. To view the callstack set at the start of the file the global variable DEBUG=true