2d:null 2e:["$","title",null,{"children":"WIP Formations from formation PR | Thomas Ballinger | Observable"}] 33:Tafe,parseFormation = src => { let title; let lines = []; let arcs = []; let curLineOrArc; let context = []; let lastIndentation = 0; for (const line of src.split('\n')) { if (!line.trim()) { continue; } const indentation = line.lastIndexOf('\t') + 1; context = context.slice(0, indentation); if (line.startsWith('formation')) { title = line.match(/formation "(.*)"/)[1]; context.push('formation'); } else if (line.trim().startsWith('flippable')) { context.push('flippable'); // this parser ignores flippable continue; } else if (line.trim().startsWith('rotatable')) { context.push('rotatable'); // this parser ignores rotatable continue; } else if (line.trim().startsWith("line")) { context.push('line'); curLineOrArc = {}; if (line.trim().split(/\s+/).length === 5) { const [, x, y, slots, direction] = line .trim() .split(/\s+/) .map(s => parseFloat(s.trim())); curLineOrArc = { anchor: { x, y }, slots, direction }; } lines.push(curLineOrArc); continue; } else if (line.trim().startsWith("repeat")) { const prev = curLineOrArc; context.push('repeat'); curLineOrArc = {}; if (line.trim().split(/\s+/).length === 3) { const [, x, y] = line .trim() .split(/\s+/) .map(s => parseFloat(s.trim())); curLineOrArc = { anchor: { x, y } }; } prev.repeat = curLineOrArc; continue; } else if ( context[context.length - 1] == 'line' || (context[context.length - 1] == 'repeat' && context[context.length - 2] == 'line') ) { if (line.trim().startsWith('start')) { const [, kw, x, y] = line.match( /start (polar|diameter)?[ ]?(\S+) (\S+)/ ); curLineOrArc.anchor = { polar: kw === 'polar', diameter: kw === 'diameter', x: parseInt(x), y: parseInt(y) }; } else if (line.trim().startsWith('slots')) { const [, slots] = line.match(/slots (\S+)/); curLineOrArc.slots = parseInt(slots); } else if (line.trim().startsWith('increase')) { const [, slots] = line.match(/increase (\S+)/); curLineOrArc.slots = parseInt(slots); } else if (line.trim().startsWith('angle')) { const [, direction] = line.match(/angle (\S+)/); curLineOrArc.direction = parseInt(direction); } else if (line.trim().startsWith('spacing')) { const [, spacing] = line.match(/spacing (\S+)/); curLineOrArc.spacing = parseInt(spacing); } } } return { title, lines: lines.map( l => new Line(l.anchor, l.slots, l.direction, l.spacing, l.repeat) ), arcs }; }34:Ta1a,// Copied from https://github.com/petervdmeer/endless-sky/blob/e008bb6f7ffae85f213b1622f05d087ea7e7cc4f/source/FormationPattern.cpp class FormationPattern { constructor(name) { this.lines = []; } static load(str) { const { title, lines, arcs } = parseFormation(str); const fp = new FormationPattern(title); fp.lines = lines; return fp; } // Get the next line that has space for placement of ships. Returns -1 if none found/available. NextLineAndRing(ring, lineNr) { // All lines participate in the first initial ring. if (ring == 0 && lineNr < this.lines.length - 1) return { ring, lineNr: lineNr + 1 }; // For later rings only lines that repeat will participate. let linesScanned = 0; while (linesScanned <= this.lines.length) { lineNr = lineNr + 1; if (lineNr >= this.lines.length) { lineNr = lineNr % this.lines.length; ring += 1; } if (this.lines[lineNr].slotsIncrease >= 0) return { ring, lineNr }; // Safety mechanism to avoid endless loops if the formation has a limited size. linesScanned++; } return { ring: -1, lineNr: -1 }; } // Get the number of positions on a line for the given ring. LineSlots(ring, lineNr) { if (lineNr >= this.lines.length) return 0; // Retrieve the relevant line. const line = this.lines[lineNr]; // For the first ring, only the initial positions are relevant. if (ring == 0) return line.initialSlots; // If we are in a later ring, then skip lines that don't repeat. if (line.slotsIncrease < 0) return 0; return line.initialSlots + line.slotsIncrease * ring; } // Get a formation position based on ring, line-number and position on the line. Position(ring, lineNr, lineSlot) { if (lineNr >= this.lines.length) return Point(); const line = this.lines[lineNr]; // Calculate position based on the initial anchor, the ring on which we are, the // line-position on the current line and the rotation of the current line. // default value for spacing; I think this is mentioned somewhere const spacing = line.spacing === undefined ? defaultSpacing : line.spacing; console.log('repeatVector.x', line.repeatVector.x); const theX = line.anchor.x + line.repeatVector.x * ring + Rotate(line.direction, Point(0, -spacing * lineSlot)).x; const theY = line.anchor.y + line.repeatVector.y * ring + Rotate(line.direction, Point(0, -spacing * lineSlot)).y; console.log(theX, theY); return Point(theX, theY); } }35:[{"id":"78d996b7210a87cdddd65ac1437284b3408413be57ce6e4cab882e4b193fadf34672aabbc5a7c77bd5ff323218ad6c4581df2afe47760a69f6805e24dd3d4038","href":"https://static.observableusercontent.com/files/78d996b7210a87cdddd65ac1437284b3408413be57ce6e4cab882e4b193fadf34672aabbc5a7c77bd5ff323218ad6c4581df2afe47760a69f6805e24dd3d4038","name":"Screen Shot 2020-06-12 at 10.35.42 AM.png","type":"image/png","lastModified":1592145943837.71,"size":1949863}] 31:{"id":"d2dc7b6061945dbf","slug":"wip-formations-from-formation-pr","title":"WIP Formations from formation PR","thumbnail":"1c20ea30bee024d95d246d23cad06a66a9b4a9dc9b73b8dd3095ec5f791f8c17","access_level":"public","create_time":"$D2020-06-14T14:45:43.837Z","update_time":"$D2020-06-14T17:43:59.008Z","view_time":null,"first_public_time":"$D2020-06-14T14:55:25.140Z","has_unpublished_edits":null,"fork":{"id":"aa9298a68f050086","slug":"review-of-formation-flying-rfc-for-endless-sky","title":"Review of Formation Flying RFC for Endless Sky","owner":{"id":"99d0de2d65d767e9","login":"ballingt-personal","name":"Thomas Ballinger"}},"stars":0,"starred":false,"owner":{"type":"team","id":"99d0de2d65d767e9","login":"ballingt-personal","name":"Thomas Ballinger","avatar_url":"https://avatars-next.observableusercontent.com/8ad92a493f85feedf6531556fe220dd29149c2e77f7de99419eb9ad4a60dc179","tier":"starter_2024"},"version":1340,"publish_version":1340,"role":null,"authored":false,"authors":[{"type":"individual","id":"f4a1ec06e8e5f9ad","login":"ballingt-personal","name":"Thomas Ballinger","avatar_url":"https://avatars-next.observableusercontent.com/8ad92a493f85feedf6531556fe220dd29149c2e77f7de99419eb9ad4a60dc179","tier":null}],"members":[{"type":"individual","id":"f4a1ec06e8e5f9ad","login":"ballingt-personal","name":"Thomas Ballinger","avatar_url":"https://avatars-next.observableusercontent.com/8ad92a493f85feedf6531556fe220dd29149c2e77f7de99419eb9ad4a60dc179","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":0,"collection":null,"type":"notebook","body":{"title":"WIP Formations from formation PR","cells":[{"id":11,"value":"md`# WIP Formations from formation PR\n\nThis is still broken! Partially because the formations in [the PR](\nThe examples with the old syntax in https://github.com/endless-sky/endless-sky/pull/4471) don't match [the spec](https://github.com/EndlessSkyCommunity/endless-sky/pull/52/files?short_path=11fd421#diff-11fd421d4722998fd5b3add63d43a05b) yet, and partially because I haven't debugged my crappy parser, which currently implements a hybrid of the spec and what I allowed to make old formations work.\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":85,"value":"html`\n

Current formations.txt from PR (click to expand)

\n${formationFlyingPRFormations}\n

\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":165,"value":"md`## Coordinate system\n\n

\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":27,"value":"md`### Trying it out\n\nI've written a quick, incomplete parser below to try out this syntax.\n\n

\n Warning: This parser is missing lots of features from [the spec](https://github.com/EndlessSkyCommunity/endless-sky/pull/52), including but not limited to arc, polar, end, skip, repeat angle, and repeat spacing.\n

\n\nThese presets are pulled from [petervdmeer's PR](https://raw.githubusercontent.com/petervdmeer/endless-sky/formation_flying/data/formations.txt).\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":711,"value":"viewof specChoice.bind(\n radio({\n title: 'Formation',\n options: Object.keys(prTexts).map(name => ({ label: name, value: name })),\n value: Object.keys(prTexts)[1]\n })\n)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":76,"value":"viewof customSpec = textarea({ rows: 10, value: prTexts[specChoice] })","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1213,"value":"FormationPattern.load(spec).lines","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":72,"value":"viewof numShips = slider({\n min: 0,\n max: 100,\n value: 15,\n step: 1,\n title: 'number of escorts'\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":475,"value":"getPositions(spec, numShips).map(p => `${p.x.toFixed(2)}, ${p.y.toFixed(2)}`)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":547,"value":"show(customSpec, numShips)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1308,"value":"viewof defaultSpacing = slider({ min: 1, max: 5, step: 1, value: 2 })","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":40,"value":"md`## Appendix\nThe JavaScript code that makes this notebook run.`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":382,"value":"Rotate = (angle, point) => {\n const rad = (Math.PI / 180) * angle;\n const x = -(Math.cos(rad) * point.x + Math.sin(rad) * point.y);\n const y = Math.cos(rad) * point.y - Math.sin(rad) * point.x;\n return Point(x, y);\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":107,"value":"$33","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":735,"value":"spec = prTexts[specChoice]","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":294,"value":"$34","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1286,"value":"viewof x = slider({min: -50, max: 50})","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1287,"value":"viewof y = slider({ min: -50, max: 50 })","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1292,"value":"viewof angle = slider({min: -360, max: 360})","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1294,"value":"newPoint = Rotate(angle, Point(x, y))","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1297,"value":"html`\n\n`","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":304,"value":"Point = (x, y) => new PointClass(x, y)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":377,"value":"class Line {\n constructor(anchor, slots, direction, spacing, repeat) {\n this.anchor = anchor;\n this.initialSlots = slots;\n this.direction = direction;\n this.spacing = spacing;\n this.repeatVector =\n repeat && repeat.anchor\n ? Point(repeat.anchor.x, repeat.anchor.y)\n : Point(0, 0);\n this.slotsIncrease = repeat ? repeat.slots || 0 : -1;\n }\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":417,"value":"class PointClass {\n constructor(x, y) {\n this.x = x;\n this.y = y;\n }\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":45,"value":"loopedYouTube = (id, muted = true) =>\n html``","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":438,"value":"{\n // side effect to make tab key enter tabs\n viewof specChoice;\n var textareas = document.getElementsByTagName('textarea');\n var count = textareas.length;\n for (var i = 0; i < count; i++) {\n textareas[i].onkeydown = function(e) {\n if (e.keyCode == 9 || e.which == 9) {\n e.preventDefault();\n var s = this.selectionStart;\n this.value =\n this.value.substring(0, this.selectionStart) +\n \"\\t\" +\n this.value.substring(this.selectionEnd);\n this.selectionEnd = s + 1;\n }\n };\n }\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":479,"value":"show = (spec, n) => {\n const positions = getPositions(spec, n);\n\n let seed = 1;\n function random() {\n var x = Math.sin(seed++) * 10000;\n return x - Math.floor(x);\n }\n\n const s = 5; // scale\n return html`\n\n`;\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":317,"value":"getPositions = (spec, n) => {\n const fp = FormationPattern.load(spec);\n\n let curRing = 0;\n let curLine = -1;\n const positions = [];\n while (true) {\n const { ring, lineNr } = fp.NextLineAndRing(curRing, curLine);\n curRing = ring;\n curLine = lineNr;\n const slots = fp.LineSlots(curRing, curLine);\n for (const pos of [...Array(slots).keys()].map(s =>\n fp.Position(curRing, curLine, s)\n )) {\n if (positions.length < n) {\n positions.push(pos);\n } else {\n return positions;\n }\n }\n }\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1233,"value":"specChoice","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":839,"value":"viewof specChoice = new View('Delta (centered)')","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":836,"value":"import { View, bind } from '@mbostock/synchronized-views'","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":68,"value":"import { slider, textarea, radio } from '@jashkenas/inputs'","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":992,"value":"formationFlyingPRFormations = await (await fetch(\n 'https://raw.githubusercontent.com/petervdmeer/endless-sky/formation_flying/data/formations.txt'\n)).text()","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":981,"value":"prTexts = {\n const texts = Array.from(\n formationFlyingPRFormations.matchAll(/\\n(formation(.|\\n)+?)\\n\\n/g)\n ).map(m => m[1]);\n const formations = {};\n for (const text of texts) {\n const name = text.match(/formation \"(.*)\"/)[1];\n formations[name] = text;\n }\n return formations;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W35","stdlib":"1","titling":"auto"}} 32:"$31:body"