I’d like to create an epg (episode guide) reader/writer to use with my legal OTA channels. So far i’ve enjoyed using Odin for a few other small projects, so I figured since Odin is a data oriented language, xml should be easy enough. With that said, I do not have much experience programmatically processing xml files, so I’m admittedly getting lost in the weeds a bit. Please forgive my ignorance.
So far I’m struggling to understand:
The example xml “utf8.xml” contains no english identities for it’s elements, making it difficult for me to reverse engineer any test output I generate.
The example odin program does not appear to do anything useful other than generate metrics, which is neat, but makes it difficult to pinpoint where anything practicle is done with (or to) the example xml.
Every parse function I try to use on the example xml file “utf8.xml” generates an EOF error. Parsing body says it expects Ident, but gets EOF. Parsing prologue says it expects “Question”. All of these elements exist in the file. Not sure what I’m doing wrong here.
Could anyone point me to an example that opens an xml file and does some basic things? Maybe even an example of creating a new xml tree and saving to file?
Here is a snippet parsing an XML document, checking that the root node is a “map” and then looping through its children:
doc, err := xml.parse(data, xml.Options{
flags={.Ignore_Unsupported},
expected_doctype="",
})
if err != nil {
panic("Failed to parse XML")
}
root := &doc.elements[0]
// Check that root element is a "map" element
assert(root.ident == "map")
// Loop through children
for child_value in root.value {
switch child in child_value {
case string:
// Not expecting text inside root noed
panic(fmt.tprintf("Unexpected string: \"%s\"", child))
case xml.Element_ID:
child_node := &doc.elements[child]
if child_node.ident == "tileset" {
// TODO: handle "tileset" node
} else if child_node.ident == "layer" {
// TODO: handle "layer" node
} else {
// Something we don't care about
fmt.printfln("Skipping top level node: %s", child_node.ident)
}
}
}
You can search through attributes of a node like this:
get_attrib :: proc(element: ^xml.Element, key: string) -> (string, bool) {
for attrib in element.attribs {
if attrib.key == key {
return attrib.val, true
}
}
return "", false
}
Thank you very much. This is an exellent start. I’m already reading and parsing a file. I see where I went wrong at the beginning: load_from_file was already parsing the file, attempting to parse further was redundant. I noticed this when I saw your return into a doc starting with parsing a data variable. I was already returning into a doc using load_from_file, so that was my data. Silly me.
Now to create and output to a new file the filtered data. Also will need to read in from a URL xml or gz data instead of loading from file. I’ll see if I can finger this out myself before asking ;).
Try working with a small, custom XML file using clear English tags first—complex examples like utf8.xml can obscure learning. Ensure the XML is well-formed and encoded in UTF-8 without BOM. Start by calling xml.load_file(path) to get a document, then use xml.get_children() or xml.get_property() to access elements. For writing, use xml.make_document() to build a tree and xml.save_file(doc, path) to write it. A minimal example that reads a simple file and extracts the id would help clarify the flow—let me know if you want one!