yxml 0.1.3
XML parsing library, nothrow @nogc, XML subset. Port of yxml.
To use this package, run the following command in your project's root directory:
Manual usage
Put the following dependency into your project's dependences section:
yxml
The yxml
DUB package is a simple library that is designed to parse a subset of XML within the constraints of restricted D.
- Allows XML parsing in
nothrow @nogc
. - One file, but depends on
numem
package for scoped DOM. - The
yxml
parser from original is fast, however the DOM it constructs isn't particularly efficient. The original library was barebones and intended to be used as SAX parser. But this is a DOM-like API.
Limitations
Not all of XML is supported. The limitations are stronger than the original yxml library.
- Comments are ignored.
- XML Processing Instructions are ignored.
- Can't parse HTML.
- Can't emit XML.
- Not validating, no namespace support.
Usage
📈 Parsing a single value in a file
// EXAMPLE: the file has this shape.
// ------------------------------------------------
// <?xml version="1.0" encoding="UTF-8"?>
// <results>
// <metric value="5.8" />
// </results>
// ------------------------------------------------
// Note: This example assumes you can use the GC for error reporting,
// but `yxml` doesn't strictly require it.
void parseMyXMLData(const(char)[] xmlData)
{
import yxml;
// Parse a whole XML file, builds a DOM.
XmlDocument doc;
doc.parse(xmlData);
// Parsing error is dealt with error codes.
if (doc.isError)
{
const(char)[] message = doc.errorMessage;
// ...do something with the error,
// such as throwing if you can:
throw new Exception(message.idup);
}
XmlElement root = doc.root;
if (root.tagName != "results")
throw new Exception("expected <results> as root XML anchor");
foreach(e; root.getChildrenByTagName("metric"))
{
if (!e.hasAttribute("value"))
throw new Exception(`expected attribute "value" in <metric>`);
return to!double(e.getAttribute("value")); // return first seen
}
throw new Exception("expected <metric>");
}
📈 Iterate children of a XmlElement
childNodes
return range that iterates on children, who are allXmlElement
themselves.childElementCount
return the number of children.
void parseCustomers(XmlElement parent)
{
// Iterate on the child nodes of `parent`
foreach(XmlElement node; parent.childNodes)
{
writeln(node.tagName); // Display <tag> name.
writeln(node.textContent); // Display its content and that of its children
}
}
🧑💼 **Pro XML parsing tip:** Use `.dup` or `.idup` to make copies of tag names of text content, because the lifetime of the DOM is the one of the `XmlDocument`. You don't want your characters string to disappear over you, right?
📈 Find a child with given tag name
- Use
XmlElement.firstChildByTagName(const(char)[] tagName)
for first matching element.
void parseCustomer(XmlElement customer)
{
XmlElement name = customer.firstChildByTagName("name");
if (name is null)
throw new Exception("<customer> has no <name>!");
}
🧑💼 **Pro XML parsing tip:** You can be even clearer in intent by using `.hasChildWithTagName`.
📈 Iterate children of a XmlElement
by tag name
getChildrenByTagName
return range that iterates on direct children that match a given tag name, no recursion.
void parseSupportDeskFile(XmlElement parent)
{
foreach(XmlElement customer; parent.getChildrenByTagName("customer"))
{
// Do something with customer
}
}
🧑💼 **Pro XML parsing tip:** Use .array to get a slice rather than a range.
import std.array; XmlElement[] elems = node.getChildrenByTagName("customer").array; writeln("%s customers found.", elems.length);
📈 Get a single attribute
void parseCustomers(XmlElement node)
{
// null if such an attribute doesn't exist
const(char)[] blurb = node.getAttribute("blurb");
if (blurb is null)
throw new Exception(`no "blurb" attribute!`);
}
// TODO iterate on attribute nodes
// TODO atribute name() and value()
- Registered by ponce
- 0.1.3 released 10 months ago
- AuburnSounds/yxml
- MIT
- Dependencies:
- numem
- Versions:
-
0.1.5 2024-Oct-07 0.1.4 2024-Aug-05 0.1.3 2024-Feb-14 0.1.2 2024-Jan-03 0.1.1 2024-Jan-03 - Download Stats:
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- Score:
- 0.4
- Short URL:
- yxml.dub.pm