Internet Engineering Task Force L.R. van Kammen Internet-Draft 7 September 2023 Intended status: Informational XR Fragments draft-XRFRAGMENTS-leonvankammen-00 Abstract This draft offers a specification for 4D URLs & navigation, to link 3D scenes and text together with- or without a network-connection. The specification promotes spatial addressibility, sharing, navigation, query-ing and tagging interactive (text)objects across for (XR) Browsers. XR Fragments allows us to enrich existing dataformats, by recursive use of existing proven technologies like URI Fragments (https://en.wikipedia.org/wiki/URI_fragment) and BibTags notation. Almost every idea in this document is demonstrated at https://xrfragment.org (https://xrfragment.org) Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on 10 March 2024. Copyright Notice Copyright (c) 2023 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/ license-info) in effect on the date of publication of this document. van Kammen Expires 10 March 2024 [Page 1] Internet-Draft XR Fragments September 2023 Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Core principle . . . . . . . . . . . . . . . . . . . . . . . 3 3. Conventions and Definitions . . . . . . . . . . . . . . . . . 3 4. List of URI Fragments . . . . . . . . . . . . . . . . . . . . 4 5. List of metadata for 3D nodes . . . . . . . . . . . . . . . . 5 6. Navigating 3D . . . . . . . . . . . . . . . . . . . . . . . . 5 7. Embedding 3D content . . . . . . . . . . . . . . . . . . . . 6 8. XR Fragment queries . . . . . . . . . . . . . . . . . . . . . 7 8.1. including/excluding . . . . . . . . . . . . . . . . . . . 8 8.2. Query Parser . . . . . . . . . . . . . . . . . . . . . . 8 8.3. XR Fragment URI Grammar . . . . . . . . . . . . . . . . . 9 9. Text in XR (tagging,linking to spatial objects) . . . . . . . 9 9.1. Default Data URI mimetype . . . . . . . . . . . . . . . . 12 9.2. URL and Data URI . . . . . . . . . . . . . . . . . . . . 13 9.3. Bibs & BibTeX: lowest common denominator for linking data . . . . . . . . . . . . . . . . . . . . . . . . . . 14 9.4. XR Text example parser . . . . . . . . . . . . . . . . . 16 10. HYPER copy/paste . . . . . . . . . . . . . . . . . . . . . . 18 11. Security Considerations . . . . . . . . . . . . . . . . . . . 18 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 13. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19 1. Introduction How can we add more features to existing text & 3D scenes, without introducing new dataformats? Historically, there's many attempts to create the ultimate markuplanguage or 3D fileformat. However, thru the lens of authoring, their lowest common denominator is still: plain text. XR Fragments allows us to enrich/connect existing dataformats, by recursive use of existing technologies: 1. addressibility and navigation of 3D scenes/objects: URI Fragments (https://en.wikipedia.org/wiki/URI_fragment) + src/href spatial metadata 2. hasslefree tagging across text and spatial objects using BibTags (https://en.wikipedia.org/wiki/BibTeX) as appendix (see visual- meta (https://visual-meta.info) e.g.) van Kammen Expires 10 March 2024 [Page 2] Internet-Draft XR Fragments September 2023 | NOTE: The chapters in this document are ordered from highlevel to | lowlevel (technical) as much as possible 2. Core principle XR Fragments strives to serve (nontechnical/fuzzy) humans first, and machine(implementations) later, by ensuring hasslefree text-vs- thought feedback loops. This also means that the repair-ability of machine-matters should be human friendly too (not too complex). | "When a car breaks down, the ones *without* turbosupercharger are | easier to fix" Let's always focus on average humans: the 'fuzzy symbolical mind' must be served first, before serving the greater 'categorized typesafe RDF hive mind' (https://en.wikipedia.org/wiki/Borg)). | Humans first, machines (AI) later. 3. Conventions and Definitions +===============+=============================================+ | definition | explanation | +===============+=============================================+ | human | a sentient being who thinks fuzzy, absorbs, | | | and shares thought (by plain text, not | | | markuplanguage) | +---------------+---------------------------------------------+ | scene | a (local/remote) 3D scene or 3D file | | | (index.gltf e.g.) | +---------------+---------------------------------------------+ | 3D object | an object inside a scene characterized by | | | vertex-, face- and customproperty data. | +---------------+---------------------------------------------+ | metadata | custom properties of text, 3D Scene or | | | Object(nodes), relevant to machines and a | | | human minority (academics/developers) | +---------------+---------------------------------------------+ | XR fragment | URI Fragment with spatial hints like | | | #pos=0,0,0&t=1,100 e.g. | +---------------+---------------------------------------------+ | src | (HTML-piggybacked) metadata of a 3D object | | | which instances content | +---------------+---------------------------------------------+ | href | (HTML-piggybacked) metadata of a 3D object | | | which links to content | +---------------+---------------------------------------------+ van Kammen Expires 10 March 2024 [Page 3] Internet-Draft XR Fragments September 2023 | query | an URI Fragment-operator which queries | | | object(s) from a scene like #q=cube | +---------------+---------------------------------------------+ | visual-meta | visual-meta (https://visual.meta.info) data | | | appended to text/books/papers which is | | | indirectly visible/editable in XR. | +---------------+---------------------------------------------+ | requestless | opposite of networked metadata (RDF/HTML | | metadata | requests can easily fan out into framerate- | | | dropping, hence not used a lot in games). | +---------------+---------------------------------------------+ | FPS | frames per second in spatial experiences | | | (games,VR,AR e.g.), should be as high as | | | possible | +---------------+---------------------------------------------+ | introspective | inward sensemaking ("I feel this belongs to | | | that") | +---------------+---------------------------------------------+ | extrospective | outward sensemaking ("I'm fairly sure John | | | is a person who lives in oklahoma") | +---------------+---------------------------------------------+ | ◻ | ascii representation of an 3D object/mesh | +---------------+---------------------------------------------+ | (un)obtrusive | obtrusive: wrapping human text/thought in | | | XML/HTML/JSON obfuscates human text into a | | | salad of machine-symbols and words | +---------------+---------------------------------------------+ | BibTeX | simple tagging/citing/referencing standard | | | for plaintext | +---------------+---------------------------------------------+ | BibTag | a BibTeX tag | +---------------+---------------------------------------------+ Table 1 4. List of URI Fragments +==========+=========+==============+============================+ | fragment | type | example | info | +==========+=========+==============+============================+ | #pos | vector3 | #pos=0.5,0,0 | positions camera to xyz- | | | | | coord 0.5,0,0 | +----------+---------+--------------+----------------------------+ | #rot | vector3 | #rot=0,90,0 | rotates camera to xyz- | | | | | coord 0.5,0,0 | +----------+---------+--------------+----------------------------+ | #t | vector2 | #t=500,1000 | sets animation-loop range | | | | | between frame 500 and 1000 | van Kammen Expires 10 March 2024 [Page 4] Internet-Draft XR Fragments September 2023 +----------+---------+--------------+----------------------------+ | #...... | string | #.cubes | object(s) of interest | | | | #cube | (fragment to object name | | | | | or class mapping) | +----------+---------+--------------+----------------------------+ Table 2 | xyz coordinates are similar to ones found in SVG Media Fragments 5. List of metadata for 3D nodes +=======+========+================+============================+ | key | type | example (JSON) | info | +=======+========+================+============================+ | name | string | "name": "cube" | available in all 3D | | | | | fileformats & scenes | +-------+--------+----------------+----------------------------+ | class | string | "class": | available through custom | | | | "cubes" | property in 3D fileformats | +-------+--------+----------------+----------------------------+ | href | string | "href": | available through custom | | | | "b.gltf" | property in 3D fileformats | +-------+--------+----------------+----------------------------+ | src | string | "src": | available through custom | | | | "#q=cube" | property in 3D fileformats | +-------+--------+----------------+----------------------------+ Table 3 Popular compatible 3D fileformats: .gltf, .obj, .fbx, .usdz, .json (THREEjs), COLLADA and so on. | NOTE: XR Fragments are file-agnostic, which means that the | metadata exist in programmatic 3D scene(nodes) too. 6. Navigating 3D Here's an ascii representation of a 3D scene-graph which contains 3D objects ◻ and their metadata: van Kammen Expires 10 March 2024 [Page 5] Internet-Draft XR Fragments September 2023 +--------------------------------------------------------+ | | | index.gltf | | │ | | ├── ◻ buttonA | | │ └ href: #pos=1,0,1&t=100,200 | | │ | | └── ◻ buttonB | | └ href: other.fbx | <-- file-agnostic (can be .gltf .obj etc) | | +--------------------------------------------------------+ An XR Fragment-compatible browser viewing this scene, allows the end- user to interact with the buttonA and buttonB. In case of buttonA the end-user will be teleported to another location and time in the *current loaded scene*, but buttonB will *replace the current scene* with a new one, like other.fbx. 7. Embedding 3D content Here's an ascii representation of a 3D scene-graph with 3D objects ◻ which embeds remote & local 3D objects ◻ (without) using queries: +--------------------------------------------------------+ +-------------------------+ | | | | | index.gltf | | ocean.com/aquarium.fbx | | │ | | │ | | ├── ◻ canvas | | └── ◻ fishbowl | | │ └ src: painting.png | | ├─ ◻ bass | | │ | | └─ ◻ tuna | | ├── ◻ aquariumcube | | | | │ └ src: ://rescue.com/fish.gltf#q=bass%20tuna | +-------------------------+ | │ | | ├── ◻ bedroom | | │ └ src: #q=canvas | | │ | | └── ◻ livingroom | | └ src: #q=canvas | | | +--------------------------------------------------------+ van Kammen Expires 10 March 2024 [Page 6] Internet-Draft XR Fragments September 2023 An XR Fragment-compatible browser viewing this scene, lazy-loads and projects painting.png onto the (plane) object called canvas (which is copy-instanced in the bed and livingroom). Also, after lazy-loading ocean.com/aquarium.gltf, only the queried objects bass and tuna will be instanced inside aquariumcube. Resizing will be happen accordingly to its placeholder object aquariumcube, see chapter Scaling. 8. XR Fragment queries Include, exclude, hide/shows objects using space-separated strings: * #q=cube * #q=cube -ball_inside_cube * #q=* -sky * #q=-.language .english * #q=cube&rot=0,90,0 * #q=price:>2 price:<5 It's simple but powerful syntax which allows css-like class/ id-selectors with a searchengine prompt-style feeling: 1. queries are showing/hiding objects *only* when defined as src value (prevents sharing of scene-tampered URL's). 2. queries are highlighting objects when defined in the top-Level (browser) URL (bar). 3. search words like cube and foo in #q=cube foo are matched against 3D object names or custom metadata-key(values) 4. search words like cube and foo in #q=cube foo are matched against tags (BibTeX) inside plaintext src values like @cube{redcube, ... e.g. 5. # equals #q=* 6. words starting with . like .german match class-metadata of 3D objects like "class":"german" 7. words starting with . like .german match class-metadata of (BibTeX) tags in XR Text objects like @german{KarlHeinz, ... e.g. | *For example*: #q=.foo is a shorthand for #q=class:foo, which will | select objects with custom property class:foo. Just a simple | #q=cube will simply select an object named cube. * see an example video here (https://coderofsalvation.github.io/xrfragment.media/queries.mp4) van Kammen Expires 10 March 2024 [Page 7] Internet-Draft XR Fragments September 2023 8.1. including/excluding +==========+=================================================+ | operator | info | +==========+=================================================+ | * | select all objects (only useful in src custom | | | property) | +----------+-------------------------------------------------+ | - | removes/hides object(s) | +----------+-------------------------------------------------+ | : | indicates an object-embedded custom property | | | key/value | +----------+-------------------------------------------------+ | . | alias for "class" :".foo" equals class:foo | +----------+-------------------------------------------------+ | > < | compare float or int number | +----------+-------------------------------------------------+ | / | reference to root-scene. | | | Useful in case of (preventing) showing/hiding | | | objects in nested scenes (instanced by src) (*) | +----------+-------------------------------------------------+ Table 4 | * = #q=-/cube hides object cube only in the root-scene (not nested | cube objects) | #q=-cube hides both object cube in the root-scene AND | nested skybox objects | » example implementation (https://github.com/coderofsalvation/xrfragment/blob/main/src/3rd/js/ three/xrf/q.js) » example 3D asset (https://github.com/coderofsalvation/xrfragment/blob/main/example/ assets/query.gltf#L192) » discussion (https://github.com/coderofsalvation/xrfragment/issues/3) 8.2. Query Parser Here's how to write a query parser: 1. create an associative array/object to store query-arguments as objects 2. detect object id's & properties foo:1 and foo (reference regex: /^.*:[><=!]?/ ) 3. detect excluders like -foo,-foo:1,-.foo,-/foo (reference regex: /^-/ ) 4. detect root selectors like /foo (reference regex: /^[-]?\// ) van Kammen Expires 10 March 2024 [Page 8] Internet-Draft XR Fragments September 2023 5. detect class selectors like .foo (reference regex: /^[-]?class$/ ) 6. detect number values like foo:1 (reference regex: /^[0-9\.]+$/ ) 7. expand aliases like .foo into class:foo 8. for every query token split string on : 9. create an empty array rules 10. then strip key-operator: convert "-foo" into "foo" 11. add operator and value to rule-array 12. therefore we we set id to true or false (false=excluder -) 13. and we set root to true or false (true=/ root selector is present) 14. we convert key '/foo' into 'foo' 15. finally we add the key/value to the store like store.foo = {id:false,root:true} e.g. | An example query-parser (which compiles to many languages) can be | found here | (https://github.com/coderofsalvation/xrfragment/blob/main/src/ | xrfragment/Query.hx) 8.3. XR Fragment URI Grammar reserved = gen-delims / sub-delims gen-delims = "#" / "&" sub-delims = "," / "=" | Example: ://foo.com/my3d.gltf#pos=1,0,0&prio=-5&t=0,100 +=============================+=================================+ | Demo | Explanation | +=============================+=================================+ | pos=1,2,3 | vector/coordinate argument e.g. | +-----------------------------+---------------------------------+ | pos=1,2,3&rot=0,90,0&q=.foo | combinators | +-----------------------------+---------------------------------+ Table 5 9. Text in XR (tagging,linking to spatial objects) We still think and speak in simple text, not in HTML or RDF. The most advanced human will probably not shout

FIRE!

in case of emergency. Given the new dawn of (non-keyboard) XR interfaces, keeping text as is (not obscuring with markup) is preferred. Ideally metadata must come *later with* text, but not *obfuscate* the text, or *in another* file. van Kammen Expires 10 March 2024 [Page 9] Internet-Draft XR Fragments September 2023 | Humans first, machines (AI) later (core principle (#core- | principle) This way: 1. XR Fragments allows hasslefree XR text tagging, using BibTeX metadata *at the end of content* (like visual-meta (https://visual.meta.info)). 2. XR Fragments allows hasslefree textual tagging, spatial tagging, and supra tagging, by mapping 3D/text object (class)names using BibTeX 'tags' 3. Bibs/BibTeX-appendices is first-choice *requestless metadata*- layer for XR text, HTML/RDF/JSON is great (but fits better in the application-layer) 4. Default font (unless specified otherwise) is a modern monospace font, for maximized tabular expressiveness (see the core principle (#core-principle)). 5. anti-pattern: hardcoupling a mandatory *obtrusive markuplanguage* or framework with an XR browsers (HTML/VRML/Javascript) (see the core principle (#core-principle)) 6. anti-pattern: limiting human introspection, by immediately funneling human thought into typesafe, precise, pre-categorized metadata like RDF (see the core principle (#core-principle)) This allows recursive connections between text itself, as well as 3D objects and vice versa, using *BibTags* : +---------------------------------------------+ +------------------+ | My Notes | | / \ | | | | / \ | | The houses here are built in baroque style. | | /house\ | | | | |_____| | | | +---------|--------+ | @house{houses, >----'house'--------| class/name match? | url = {#.house} >----'houses'-------` class/name match? | } | +---------------------------------------------+ This allows instant realtime tagging of objects at various scopes: van Kammen Expires 10 March 2024 [Page 10] Internet-Draft XR Fragments September 2023 +====================================+=============================+ | scope | matching algo | +====================================+=============================+ | textual | now automatically tagged | | | with 'house' (incl. | | | plaintext src child nodes) | +------------------------------------+-----------------------------+ | spatial | "class":"house" (because of | | | {#.house}) are now | | | automatically tagged with | | | 'house' (incl. child nodes) | +------------------------------------+-----------------------------+ | supra | text- or spatial-object(s) | | | (non-descendant nodes) | | | elsewhere, named 'house', | | | are automatically tagged | | | with 'house' (current node | | | to root node) | +------------------------------------+-----------------------------+ | omni | text- or spatial-object(s) | | | (non-descendant nodes) | | | elsewhere, containing | | | class/name 'house', are | | | automatically tagged with | | | 'house' (too node to all | | | nodes) | +------------------------------------+-----------------------------+ | infinite | (non-descendant nodes) | | | elsewhere, containing | | | class/name 'house' or | | | 'houses', are automatically | | | tagged with 'house' (too | | | node to all nodes) | +------------------------------------+-----------------------------+ Table 6 This empowers the enduser spatial expressiveness (see the core principle (#core-principle)): spatial wires can be rendered, words can be highlighted, spatial objects can be highlighted/moved/scaled, links can be manipulated by the user. The simplicity of appending BibTeX 'tags' (humans first, machines later) is also demonstrated by visual-meta (https://visual-meta.info) in greater detail. van Kammen Expires 10 March 2024 [Page 11] Internet-Draft XR Fragments September 2023 1. The XR Browser needs to adjust tag-scope based on the endusers needs/focus (infinite tagging only makes sense when environment is scaled down significantly) 2. The XR Browser should always allow the human to view/edit the metadata, by clicking 'toggle metadata' on the 'back' (contextmenu e.g.) of any XR text, anywhere anytime. | NOTE: infinite matches both 'house' and 'houses' in text, as well | as spatial objects with "class":"house" or name "house". This | multiplexing of id/category is deliberate because of the core | principle (#core-principle). 9.1. Default Data URI mimetype The src-values work as expected (respecting mime-types), however: The XR Fragment specification bumps the traditional default browser- mimetype text/plain;charset=US-ASCII to a green eco-friendly: text/plain;charset=utf-8;bib=^@ This indicates that bibs (https://github.com/coderofsalvation/ tagbibs) and bibtags (https://en.wikipedia.org/wiki/BibTeX) matching regex ^@ will automatically get filtered out, in order to: * automatically detect links between textual/spatial objects * detect opiniated bibtag appendices (visual-meta (https://visual- meta.info) e.g.) It's concept is similar to literate programming, which empower local/ remote responses to: * (de)multiplex human text and metadata in one go (see the core principle (#core-principle)) * no network-overhead for metadata (see the core principle (#core- principle)) * ensuring high FPS: HTML/RDF historically is too 'requesty'/'parsy' for game studios * rich send/receive/copy-paste everywhere by default, metadata being retained (see the core principle (#core-principle)) * netto result: less webservices, therefore less servers, and overall better FPS in XR van Kammen Expires 10 March 2024 [Page 12] Internet-Draft XR Fragments September 2023 | This significantly expands expressiveness and portability of human | tagged text, by *postponing machine-concerns to the end of the | human text* in contrast to literal interweaving of content and | markupsymbols (or extra network requests, webservices e.g.). For all other purposes, regular mimetypes can be used (but are not required by the spec). To keep XR Fragments a lightweight spec, BibTeX is used for text/ spatial tagging (not a scripting language or RDF e.g.). | Applications are also free to attach any JSON(LD / RDF) to spatial | objects using custom properties (but is not interpreted by this | spec). 9.2. URL and Data URI +--------------------------------------------------------------+ +------------------------+ | | | author.com/article.txt | | index.gltf | +------------------------+ | │ | | | | ├── ◻ article_canvas | | Hello friends. | | │ └ src: ://author.com/article.txt | | | | │ | | @friend{friends | | └── ◻ note_canvas | | ... | | └ src:`data:welcome human\n@...` | | } | | | +------------------------+ | | +--------------------------------------------------------------+ The enduser will only see welcome human and Hello friends rendered spatially. The beauty is that text (AND visual-meta) in Data URI promotes rich copy-paste. In both cases, the text gets rendered immediately (onto a plane geometry, hence the name '_canvas'). The XR Fragment-compatible browser can let the enduser access visual- meta(data)-fields after interacting with the object (contextmenu e.g.). | additional tagging using bibs | (https://github.com/coderofsalvation/tagbibs): to tag spatial | object note_canvas with 'todo', the enduser can type or speak | @note_canvas@todo The mapping between 3D objects and text (src-data) is simple (the : Example: van Kammen Expires 10 March 2024 [Page 13] Internet-Draft XR Fragments September 2023 +------------------------------------------------+ | | | index.gltf | | │ | | └── ◻ rentalhouse | | └ class: house <----------------- matches -------+ | └ ◻ note | | | └ src:`data: todo: call owner | bib | | @owner@house@todo | ----> expands to @house{owner, | | bibtex: } | ` | @contact{ +------------------------------------------------+ } Bi-directional mapping between 3D object names and/or classnames and text using bibs,BibTags & XR Fragments, allows for rich interlinking between text and 3D objects: 1. When the user surfs to https://.../index.gltf#rentalhouse the XR Fragments-parser points the enduser to the rentalhouse object, and can show contextual info about it. 2. When (partial) remote content is embedded thru XR Fragment queries (see XR Fragment queries), indirectly related metadata can be embedded along. 9.3. Bibs & BibTeX: lowest common denominator for linking data | "When a car breaks down, the ones *without* turbosupercharger are | easier to fix" Unlike XML or JSON, the typeless, unnested, everything-is-text nature of BibTeX tags is a great advantage for introspection. It's a missing sensemaking precursor to extrospective RDF. BibTeX-appendices are already used in the digital AND physical world (academic books, visual-meta (https://visual-meta.info)), perhaps due to its terseness & simplicity. In that sense, it's one step up from the .ini fileformat (which has never leaked into the physical world like BibTex): 1. frictionless copy/pasting (by humans) of (unobtrusive) content AND metadata 2. an introspective 'sketchpad' for metadata, which can (optionally) mature into RDF later van Kammen Expires 10 March 2024 [Page 14] Internet-Draft XR Fragments September 2023 +================+=====================================+===============+ |characteristic |UTF8 Plain Text (with BibTeX) |RDF | +================+=====================================+===============+ |perspective |introspective |extrospective | +----------------+-------------------------------------+---------------+ |structure |fuzzy (sensemaking) |precise | +----------------+-------------------------------------+---------------+ |space/scope |local |world | +----------------+-------------------------------------+---------------+ |everything is |yes |no | |text (string) | | | +----------------+-------------------------------------+---------------+ |voice/paper- |bibs |no | |friendly |(https://github.com/coderofsalvation/| | | |tagbibs) | | +----------------+-------------------------------------+---------------+ |leaves |yes |no | |(dictated) text | | | |intact | | | +----------------+-------------------------------------+---------------+ |markup language |just an appendix |~4 different | +----------------+-------------------------------------+---------------+ |polyglot format |no |yes | +----------------+-------------------------------------+---------------+ |easy to copy/ |yes |up to | |paste | |application | |content+metadata| | | +----------------+-------------------------------------+---------------+ |easy to write/ |yes |depends | |repair for | | | |layman | | | +----------------+-------------------------------------+---------------+ |easy to |yes (fits on A4 paper) |depends | |(de)serialize | | | +----------------+-------------------------------------+---------------+ |infrastructure |selfcontained (plain text) |(semi)networked| +----------------+-------------------------------------+---------------+ |freeform |yes, terse |yes, verbose | |tagging/ | | | |annotation | | | +----------------+-------------------------------------+---------------+ |can be appended |yes |up to | |to text-content | |application | +----------------+-------------------------------------+---------------+ |copy-paste text |yes |up to | |preserves | |application | |metadata | | | +----------------+-------------------------------------+---------------+ van Kammen Expires 10 March 2024 [Page 15] Internet-Draft XR Fragments September 2023 |emoji |yes |depends on | | | |encoding | +----------------+-------------------------------------+---------------+ |predicates |free |semi pre- | | | |determined | +----------------+-------------------------------------+---------------+ |implementation/ |no |depends | |network overhead| | | +----------------+-------------------------------------+---------------+ |used in |yes (visual-meta) |no | |(physical) | | | |books/PDF | | | +----------------+-------------------------------------+---------------+ |terse non-verb |yes |no | |predicates | | | +----------------+-------------------------------------+---------------+ |nested |no (but: BibTex rulers) |yes | |structures | | | +----------------+-------------------------------------+---------------+ Table 7 9.4. XR Text example parser 1. The XR Fragments spec does not aim to harden the BiBTeX format 2. However, respect multi-line BibTex values because of the core principle (#core-principle) 3. Expand bibs and rulers (like ${visual-meta-start}) according to the tagbibs spec (https://github.com/coderofsalvation/tagbibs) 4. BibTeX snippets should always start in the beginning of a line (regex: ^@), hence mimetype text/plain;charset=utf-8;bib=^@ Here's an XR Text (de)multiplexer in javascript, which ticks all the above boxes: xrtext = { decode: (str) => { // bibtex: ↓@ ↓ ↓property ↓end let pat = [ /@/, /^\S+[,{}]/, /},/, /}/ ] let tags = [], text='', i=0, prop='' var bibs = { regex: /(@[a-zA-Z0-9_+]+@[a-zA-Z0-9_@]+)/g, tags: {}} let lines = str.replace(/\r?\n/g,'\n').split(/\n/) for( let i = 0; !lines[i].match( /^@/ ); i++ ) text += lines[i]+'\n' bibtex = lines.join('\n').substr( text.length ) bibtex.replace( bibs.regex , (m,k,v) => { tok = m.substr(1).split("@") van Kammen Expires 10 March 2024 [Page 16] Internet-Draft XR Fragments September 2023 match = tok.shift() tok.map( (t) => bibs.tags[match] = `@${t}{${match},\n}\n` ) }) bibtex = Object.values(bibs.tags).join('\n') + bibtex.replace( bibs.regex, '') bibtex.split( pat[0] ).map( (t) => { try{ let v = {} if( !(t = t.trim()) ) return if( tag = t.match( pat[1] ) ) tag = tag[0] if( tag.match( /^{.*}$/ ) ) return tags.push({ruler:tag}) t = t.substr( tag.length ) t.split( pat[2] ) .map( kv => { if( !(kv = kv.trim()) || kv == "}" ) return v[ kv.match(/\s?(\S+)\s?=/)[1] ] = kv.substr( kv.indexOf("{")+1 ) }) tags.push( { k:tag, v } ) }catch(e){ console.error(e) } }) return {text, tags} }, encode: (text,tags) => { let str = text+"\n" for( let i in tags ){ let item = tags[i] if( item.ruler ){ str += `@${item.ruler}\n` continue; } str += `@${item.k}\n` for( let j in item.v ) str += ` ${j} = {${item.v[j]}}\n` str += `}\n` } return str } } The above functions (de)multiplexe text/metadata, expands bibs, (de)serialize bibtex (and all fits more or less on one A4 paper) | above can be used as a startingpoint for LLVM's to translate/ | steelman to a more formal form/language. van Kammen Expires 10 March 2024 [Page 17] Internet-Draft XR Fragments September 2023 str = ` hello world @hello@greeting @{some-section} @flap{ asdf = {23423} }` var {tags,text} = xrtext.decode(str) // demultiplex text & bibtex tags.find( (t) => t.k == 'flap{' ).v.asdf = 1 // edit tag tags.push({ k:'bar{', v:{abc:123} }) // add tag console.log( xrtext.encode(text,tags) ) // multiplex text & bibtex back together This outputs: hello world @greeting{hello, } @{some-section} @flap{ asdf = {1} } @bar{ abc = {123} } 10. HYPER copy/paste The previous example, offers something exciting compared to simple copy/paste of 3D objects or text. XR Text according to the XR Fragment spec, allows HYPER-copy/paste: time, space and text interlinked. Therefore, the enduser in an XR Fragment-compatible browser can copy/paste/share data in these ways: 1. time/space: 3D object (current animation-loop) 2. text: TeXt object (including BibTeX/visual-meta if any) 3. interlinked: Collected objects by visual-meta tag 11. Security Considerations Since XR Text contains metadata too, the user should be able to set up tagging-rules, so the copy-paste feature can : * filter out sensitive data when copy/pasting (XR text with class:secret e.g.) van Kammen Expires 10 March 2024 [Page 18] Internet-Draft XR Fragments September 2023 12. IANA Considerations This document has no IANA actions. 13. Acknowledgments TODO acknowledge. van Kammen Expires 10 March 2024 [Page 19]