Module xml_scan 

Lightweight XML element and attribute extraction utilities.

These functions use simple string scanning rather than full XML parsing. They are intentionally limited: they handle the flat, predictable element structures found in ISO 20022 messages but do not handle CDATA, comments, or namespace-qualified attributes.

Migration to typed validation

New code should prefer the typed validation path (SchemeValidator::validate_typed) which accesses fields directly on deserialized message structs. The xml_scan utilities remain available for cases where raw XML is the only input (e.g. CLI validation without deserialization).

Limitations

• Element extraction is first-match only (use extract_all_elements for repeated elements).
• Namespace prefixes on tags are not handled — match against the local name only.
• Attribute extraction searches the whole document, not a specific element.

Functions

extract_all_attributes

Extract all values of a named XML attribute (e.g. Ccy="USD") from xml.

extract_all_elements

Extract the text content of every <tag>value</tag> in xml.

extract_attribute

Extract the value of a named attribute on a specific element tag.

extract_element

Extract the text content of the first <tag>value</tag> in xml.

has_element

Return true if the given tag appears anywhere in xml.

xml_byte_size

Return the UTF-8 byte length of the XML string.