OCaml HTML5 parser/serialiser based on Python's JustHTML
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lib/html5_checker/specialized/unknown_element_checker.ml
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lib/html5_checker/specialized/unknown_element_checker.ml
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(** Unknown HTML element checker.
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Detects elements that are not in the HTML5 specification and produces
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appropriate error messages. Custom elements (with hyphens) are allowed. *)
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(** Set of all known HTML5 element names. *)
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let known_elements =
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let elements = [
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(* Document metadata *)
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"html"; "head"; "title"; "base"; "link"; "meta"; "style";
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(* Sections *)
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"body"; "article"; "section"; "nav"; "aside"; "h1"; "h2"; "h3"; "h4"; "h5"; "h6";
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"hgroup"; "header"; "footer"; "address"; "main";
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(* Grouping content *)
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"p"; "hr"; "pre"; "blockquote"; "ol"; "ul"; "menu"; "li"; "dl"; "dt"; "dd";
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"figure"; "figcaption"; "div";
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(* Text-level semantics *)
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"a"; "em"; "strong"; "small"; "s"; "cite"; "q"; "dfn"; "abbr"; "ruby"; "rt"; "rp";
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"data"; "time"; "code"; "var"; "samp"; "kbd"; "sub"; "sup"; "i"; "b"; "u"; "mark";
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"bdi"; "bdo"; "span"; "br"; "wbr"; "search";
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(* Edits *)
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"ins"; "del";
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(* Embedded content *)
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"picture"; "source"; "img"; "iframe"; "embed"; "object"; "video"; "audio";
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"track"; "map"; "area"; "math"; "svg";
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(* Tables *)
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"table"; "caption"; "colgroup"; "col"; "tbody"; "thead"; "tfoot"; "tr"; "td"; "th";
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(* Forms *)
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"form"; "label"; "input"; "button"; "select"; "datalist"; "optgroup"; "option";
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"textarea"; "output"; "progress"; "meter"; "fieldset"; "legend";
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(* Interactive *)
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"details"; "summary"; "dialog";
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(* Scripting *)
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"script"; "noscript"; "template"; "slot"; "canvas";
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(* Deprecated but still recognized *)
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"param";
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] in
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let tbl = Hashtbl.create (List.length elements) in
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List.iter (fun el -> Hashtbl.add tbl el ()) elements;
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tbl
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(** Check if an element name is a custom element (contains hyphen). *)
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let is_custom_element name =
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String.contains name '-'
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(** Check if an element name is known. *)
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let is_known_element name =
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let name_lower = String.lowercase_ascii name in
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Hashtbl.mem known_elements name_lower || is_custom_element name_lower
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type state = {
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mutable stack : string list; (* Parent element stack *)
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}
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let create () = { stack = [] }
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let reset state =
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state.stack <- []
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let start_element state ~name ~namespace ~attrs:_ collector =
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(* Only check HTML namespace elements *)
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match namespace with
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| Some _ -> () (* Skip SVG, MathML, etc. *)
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| None ->
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let name_lower = String.lowercase_ascii name in
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(* Check if element is unknown *)
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if not (is_known_element name_lower) then begin
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(* Get the parent element name *)
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let parent = match state.stack with
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| p :: _ -> p
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| [] -> "document"
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in
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(* Produce error: unknown element not allowed as child *)
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Message_collector.add_typed collector
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(Error_code.Element_not_allowed_as_child { child = name; parent })
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end;
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(* Always push to stack for tracking *)
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state.stack <- name_lower :: state.stack
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let end_element state ~name:_ ~namespace _ =
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match namespace with
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| Some _ -> ()
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| None ->
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match state.stack with
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| _ :: rest -> state.stack <- rest
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| [] -> () (* Stack underflow - shouldn't happen *)
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let characters _state _text _collector = ()
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let end_document _state _collector = ()
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let checker =
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(module struct
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type nonrec state = state
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let create = create
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let reset = reset
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let start_element = start_element
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let end_element = end_element
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let characters = characters
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let end_document = end_document
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end : Checker.S)