Zig

Removing / Deleting Child Nodes from XML

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Demonstrates various methods for removing child nodes from an XML document.

The input XML, available at http://www.chilkatsoft.com/data/fruit.xml, is this:

<root>
    <fruit color="red">apple</fruit>
    <fruit color="green">pear</fruit>
    <veg color="orange">carrot</veg>
    <meat animal="cow">beef</meat>
    <xyz>
        <fruit color="blue">blueberry</fruit>
        <veg color="green">broccoli</veg>
    </xyz>
    <fruit color="purple">grape</fruit>
    <cheese color="yellow">cheddar</cheese>
</root>

Zig

const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

    const xml = try chilkat.Xml.init();
    defer xml.deinit();

    // The sample input XML is available at http://www.chilkatsoft.com/data/fruit.xml
    xml.loadXmlFile("fruit.xml") catch {
        std.debug.print("{s}\n", .{try xml.getLastErrorText(alloc)});
        return;
    };

    // The RemoveChild method removes (discards) all direct
    // children having the specified tag:
    xml.removeChild("fruit");

    // Show the resulting XML:
    std.debug.print("Result with all direct children having a tag equal to \"fruit\" removed:\n", .{});
    std.debug.print("{s}\n", .{try xml.getXml(alloc)});

    // The XML with the "fruit" direct children removed is shown below:
    // Notice that the "fruit" node beneath "xyz" was not removed.
    // This correct because it was not a direct child of the calling node.

    // <root>
    //     <veg color="orange">carrot</veg>
    //     <meat animal="cow">beef</meat>
    //     <xyz>
    //         <fruit color="blue">blueberry</fruit>
    //         <veg color="green">broccoli</veg>
    //     </xyz>
    //     <cheese color="yellow">cheddar</cheese>
    // </root>

    // --------------------------------------------------------------------------
    // Restore the original XML:
    try xml.loadXmlFile("fruit.xml");

    // The RemoveChildWithContent method removes the child
    // having the exact content specified, regardless of the tag.
    // For example:
    xml.removeChildWithContent("pear");

    // Show the resulting XML:
    std.debug.print("Result with the node containing \"pear\" removed:\n", .{});
    std.debug.print("{s}\n", .{try xml.getXml(alloc)});

    // --------------------------------------------------------------------------
    // Restore the original XML:
    try xml.loadXmlFile("fruit.xml");

    // The RemoveChildByIndex method removes the Nth direct
    // child.  Indexing begins at 0.  The "xyz" child is at index 4:
    xml.removeChildByIndex(4);

    // Show the resulting XML:
    // Notice that the entire "xyz" subtree is removed.
    std.debug.print("Result with the node at index 4 removed:\n", .{});
    std.debug.print("{s}\n", .{try xml.getXml(alloc)});

    // --------------------------------------------------------------------------
    // Restore the original XML:
    try xml.loadXmlFile("fruit.xml");

    // Navigate to the node with tag "xyz";
    const xyz = try xml.findChild("xyz");
    defer xyz.deinit();

    // Remove the "xyz" subtree making it it's own XML document
    // with the "xyz" node at the root:
    xyz.removeFromTree();

    // Show both XML documents:
    std.debug.print("{s}\n", .{try xyz.getXml(alloc)});
    std.debug.print("{s}\n", .{try xml.getXml(alloc)});

    // Also, the TreeId property is an integer value assigned
    // to nodes in an XML document.  All nodes belonging to
    // the same XML document will have the same TreeId.
    // Notice that the "xyz" node now has a different TreeId:
    std.debug.print("xyz TreeId = {d}\n", .{xyz.getTreeId()});
    std.debug.print("xml TreeId = {d}\n", .{xml.getTreeId()});
}