Minimal streaming XML pull-parser and writer

Author

Version

0.1.0

License

Apache-2.0

Repository

github.com/marianoguerra/syndication

Last updated

2 months ago

Downloads

No dependencies

#marianoguerra/xml

A minimal, dependency-free streaming XML pull-parser and writer for MoonBit, in the spirit of Rust's quick-xml.

Reader: Event stream (Start, Empty, End, Text, CData, Comment, Eof) with predefined + numeric entity decoding. Malformed markup raises XmlError::Syntax with a code-unit offset.
Writer: escaping helpers (escape_text, escape_attr), CDATA section splitting, namespace-free element emission.

///|
test {
  let r = @xml.Reader::new("<a k=\"v &amp; co\">text</a>")
  let ev1 = try! r.next()
  let ev2 = try! r.next()
  assert_true(ev1 is Start(name="a", attrs=[{ key: "k", value: "v & co" }]))
  assert_true(ev2 is Text("text"))
}

The parser intentionally does not validate DTDs or resolve external entities. Processing instructions and DOCTYPE declarations are skipped.

XmlError

source

pub(all) suberror XmlError {
  Syntax(pos~ : Int, msg~ : String)
} derive(Eq, @moonbitlang/core/debug.Debug
Debug)

Errors raised while scanning malformed XML.

Attribute

source

pub struct Attribute {
  key : String
  value : String
} derive(Eq, @moonbitlang/core/debug.Debug
Debug)

A single attribute of an XML start tag.

Event

source

pub(all) enum Event {
  Start(name~ : String, attrs~ : Array[Attribute])
  Empty(name~ : String, attrs~ : Array[Attribute])
  End(String)
  Text(String)
  CData(String)
  Comment(String)
  Eof
} derive(Eq, @moonbitlang/core/debug.Debug
Debug)

A streaming XML event.

Reader

source

pub struct Reader {
  // private fields
} derive(@moonbitlang/core/debug.Debug
Debug)

A pull-parser over an in-memory XML document.

The parser is lenient about constructs that do not affect RSS/Atom interpretation (processing instructions and DOCTYPE declarations are skipped) but strict about malformed tags, attributes and CDATA sections.

Reader::new

source

fn Reader::new(input : String) -> Reader

Create a reader over input. A leading BOM is skipped.

Reader::next

source

fn Reader::next(self : Reader) -> Event raise XmlError

Scan and return the next event.

Reader::position

source

fn Reader::position(self : Reader) -> Int

Current code-unit offset of the scanner (for diagnostics).

Writer

source

pub struct Writer {
  // private fields
} derive(@moonbitlang/core/debug.Debug
Debug)

A minimal streaming XML writer.

Writer::cdata

source

fn Writer::cdata(self : Writer, content : String) -> Unit

Write a CDATA section, splitting any ]]> occurrences so the section stays well-formed.

Writer::close

source

fn Writer::close(self : Writer, name : String) -> Unit

Write a closing tag </name>.

Writer::empty

source

fn Writer::empty(self : Writer, name : String, attrs? : Array[(String, String)]) -> Unit

Write a self-closing tag; attributes are escaped.

Writer::new

source

fn Writer::new() -> Writer

Writer::open

source

fn Writer::open(self : Writer, name : String) -> Unit

Write an opening tag <name>.

Writer::open_with

source

fn Writer::open_with(self : Writer, name : String, attrs~ : Array[(String, String)]) -> Unit

Write an opening tag with attributes, <name k="v" ...>. Attribute values are escaped.

Writer::raw

source

fn Writer::raw(self : Writer, content : String) -> Unit

Write pre-escaped / raw markup. The caller guarantees well-formedness.

Writer::text

source

fn Writer::text(self : Writer, content : String) -> Unit

Write escaped character data.

Writer::to_string

source

fn Writer::to_string(self : Writer) -> String

Return the accumulated document.

Writer::write_decl

source

fn Writer::write_decl(self : Writer) -> Unit

Write the XML declaration used by RSS/Atom output.

decode_entities

source

fn decode_entities(input : String) -> String

Decode predefined (& < > " ') and numeric (&#NNN;, &#xHHH;) character references. Unknown or malformed references are left verbatim (lenient, mirroring quick-xml defaults).

escape_attr

source

fn escape_attr(s : String) -> String

Escape attribute-value content.

escape_text

source

fn escape_text(s : String) -> String

Escape text-node content.

local_name

source

fn local_name(qname : String) -> String

The local part of a qualified name: "itunes:author" → "author".

prefix_of

source

fn prefix_of(qname : String) -> String?

The prefix part of a qualified name, or None when unprefixed.

split_qname

source

fn split_qname(qname : String) -> (String?, String)

Split a qualified name into (prefix?, local). "itunes:author" becomes (Some("itunes"), "author"); "title" becomes (None, "title").

trim

source

fn trim(s : String) -> String

Trim ASCII whitespace from both ends.

Source Files

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xml

#marianoguerra/xml

#XmlError

#Attribute

#Event

#Reader

#Reader::new

#Reader::next

#Reader::position

#Writer

#Writer::cdata

#Writer::close

#Writer::empty

#Writer::new

#Writer::open

#Writer::open_with

#Writer::raw

#Writer::text

#Writer::to_string

#Writer::write_decl

#decode_entities

#escape_attr

#escape_text

#local_name

#prefix_of

#split_qname

#trim

Source Files

XmlError

Attribute

Event

Reader

Reader::new

Reader::next

Reader::position

Writer

Writer::cdata

Writer::close

Writer::empty

Writer::new

Writer::open

Writer::open_with

Writer::raw

Writer::text

Writer::to_string

Writer::write_decl

decode_entities

escape_attr

escape_text

local_name

prefix_of

split_qname

trim