2e:null 2f:["$","title",null,{"children":"TypeScript (subset) -> Elm | Jakub Hampl | Observable"}] 34:Tbec,input = ` function log10Floor (n: number) : number { return Math.floor(Math.log10(n)); } function arrJoin(arr : string[], v: string): string { return arr.join(v); } /** * When the ToRawPrecision abstract operation is called with arguments x (which * must be a finite non-negative number), minPrecision, and maxPrecision (both * must be integers between 1 and 21) the following steps are taken: */ function ToRawPrecision (x : number, minPrecision : number, maxPrecision : number) : string { // 1. Let p be maxPrecision. let p = maxPrecision; let m, e; // 2. If x = 0, then if (x === 0) { // a. Let m be the String consisting of p occurrences of the character "0". m = arrJoin.call(Array (p + 1), '0'); // b. Let e be 0. e = 0; } // 3. Else else { // a. Let e and n be integers such that 10ᵖ⁻¹ ≤ n < 10ᵖ and for which the // exact mathematical value of n × 10ᵉ⁻ᵖ⁺¹ – x is as close to zero as // possible. If there are two such sets of e and n, pick the e and n for // which n × 10ᵉ⁻ᵖ⁺¹ is larger. e = log10Floor(Math.abs(x)); // Easier to get to m from here let f = Math.round(Math.exp((Math.abs(e - p + 1)) * Math.LN10)); // b. Let m be the String consisting of the digits of the decimal // representation of n (in order, with no leading zeroes) m = String(Math.round(e - p + 1 < 0 ? x * f : x / f)); } // 4. If e ≥ p, then if (e >= p) // a. Return the concatenation of m and e-p+1 occurrences of the character "0". return m + arrJoin.call(Array(e-p+1 + 1), '0'); // 5. If e = p-1, then else if (e === p - 1) // a. Return m. return m; // 6. If e ≥ 0, then else if (e >= 0) // a. Let m be the concatenation of the first e+1 characters of m, the character // ".", and the remaining p–(e+1) characters of m. m = m.slice(0, e + 1) + '.' + m.slice(e + 1); // 7. If e < 0, then else if (e < 0) // a. Let m be the concatenation of the String "0.", –(e+1) occurrences of the // character "0", and the string m. m = '0.' + arrJoin.call(Array (-(e+1) + 1), '0') + m; // 8. If m contains the character ".", and maxPrecision > minPrecision, then if (m.indexOf(".") >= 0 && maxPrecision > minPrecision) { // a. Let cut be maxPrecision – minPrecision. let cut = maxPrecision - minPrecision; // b. Repeat while cut > 0 and the last character of m is "0": while (cut > 0 && m.charAt(m.length-1) === '0') { // i. Remove the last character from m. m = m.slice(0, -1); // ii. Decrease cut by 1. cut--; } // c. If the last character of m is ".", then if (m.charAt(m.length-1) === '.') // i. Remove the last character from m. m = m.slice(0, -1); } // 9. Return m. return m; } `35:T4eb,program = { ts.setSys({ useCaseSensitiveFileNames: true, getExecutingFilePath() { return ""; }, getCurrentDirectory() { return ""; }, directoryExists() { return true; }, getDirectories() { return []; } }); const tsOptions = { strict: true, allowUnreachableCode: false, allowUnusedLabels: false, exactOptionalPropertyTypes: true, noImplicitReturns: true }; const files = { "input.ts": ts.createSourceFile("input.ts", input, ts.ScriptTarget.Latest) }; console.log(ts.getDefaultCompilerOptions()); const host = ts.createCompilerHost({ useCaseSensitiveFileNames: true }); const orig = host.getSourceFile; host.getSourceFile = (fileName, languageVersion, onError) => { if (files[fileName]) return files[fileName]; return orig(fileName, languageVersion, onError); }; let program = ts.createProgram(["input.ts"], tsOptions, host); let checker = program.getTypeChecker(); const diagnostics = program.getBindAndCheckDiagnostics(files["input.ts"]); if (diagnostics && diagnostics.length > 0) { console.warn(diagnostics); throw `Failed to compile: ${diagnostics .map((d) => d.messageText) .join("\n")}`; } return program; }36:T18bb,handleNode = { let name; const handleNode = (node, context = "stmt") => { // Note: there are over 300 cases for node.kind, so this would take a while // to implement... switch (node.kind) { case ts.SyntaxKind.SourceFile: return `module Output exposing (${node.statements .filter((s) => s.modifiers?.some((m) => m.kind === ts.SyntaxKind.ExportKeyword) ) .flatMap((s) => s.declarationList.declarations.map((d) => d.name.escapedText) )})\n\n${node.statements.map(handleNode).join("\n\n")}`; case ts.SyntaxKind.TypeAliasDeclaration: return `type alias ${node.name.getText()} =\n ${handleNode( node.type, "type" )}`; case ts.SyntaxKind.TypeLiteral: return `{ ${node.members .map((n) => handleNode(n, "type")) .join("\n , ")} }`; case ts.SyntaxKind.PropertySignature: return `${node.name.getText()} : ${handleNode(node.type, "type")}`; case ts.SyntaxKind.NumberKeyword: return `Float`; case ts.SyntaxKind.FunctionType: return `${node.parameters .map((n) => handleNode(n, "type")) .join(" -> ")} -> ${handleNode(node.type, "type")}`; case ts.SyntaxKind.Parameter: if (context == "type") { return handleNode(node.type); } else { return node.name.escapedText; } case ts.SyntaxKind.TypeReference: return node.typeName.escapedText; case ts.SyntaxKind.ArrayType: console.log(node); return `List ${handleNode(node.elementType, "type")}`; case ts.SyntaxKind.VariableStatement: return handleNode(node.declarationList); case ts.SyntaxKind.VariableDeclarationList: return node.declarations.map(handleNode).join("\n\n"); case ts.SyntaxKind.VariableDeclaration: name = node.name.escapedText; return `${name} : ${makeTypeSignature(node)}\n${name} =\n${indent( handleNode(node.initializer) )}`; case ts.SyntaxKind.FunctionDeclaration: name = node.name.escapedText; return `${name} : ${makeTypeSignature(node)}\n${name} ${node.parameters .map(handleNode) .join(" ")} =\n${indent(handleNode(node.body))}`; case ts.SyntaxKind.ArrowFunction: return `(\\${node.parameters.map(handleNode).join(" ")} -> ${handleNode( node.body )})`; case ts.SyntaxKind.Block: if ( node.statements.length == 1 && node.statements[0].kind === ts.SyntaxKind.ReturnStatement ) { return handleNode(node.statements[0].expression); } else if ( node.statements[node.statements.length - 1].kind === ts.SyntaxKind.ReturnStatement ) { const statemets = [...node.statements]; const returnS = statemets.pop().expression; return `\n let\n${indent( indent(statemets.map(handleNode).join("\n\n ")) )}\n in\n ${handleNode(returnS)}`; } else { throw `Can't translate an Arrow Function that is only run for side effects`; } case ts.SyntaxKind.BinaryExpression: switch (node.operatorToken.getText()) { case "%": return `${handleNode(node.left)} |> modBy ${handleNode( node.right )}`; default: return `${handleNode( node.left )} ${node.operatorToken.getText()} ${handleNode(node.right)}`; } case ts.SyntaxKind.PropertyAccessExpression: return `${handleNode(node.expression)}.${node.name.escapedText}`; case ts.SyntaxKind.Identifier: return node.escapedText; case ts.SyntaxKind.NumericLiteral: return node.text; case ts.SyntaxKind.CallExpression: return translateApiCalls(node); case ts.SyntaxKind.ObjectLiteralExpression: return `{ ${node.properties.map(handleNode).join(", ")} }`; case ts.SyntaxKind.PropertyAssignment: return `${node.name.escapedText} = ${handleNode(node.initializer)}`; case ts.SyntaxKind.ArrayLiteralExpression: return `[ ${node.elements.map(handleNode).join(", ")} ]`; default: console.log(node); throw `node kind ${node.kind} is not supported`; } }; const makeTypeSignature = (node) => { const type = checker.getTypeAtLocation(node); console.log(type, checker.typeToString(type)); if (type.isLiteral()) { if (type.isNumberLiteral()) { return "Float"; } else { throw "unsupported literal"; } } else { return handleNode( checker.typeToTypeNode(checker.getTypeAtLocation(node)) ); } }; const translateApiCalls = (node) => { // there is probably a better way to do this using signatures and/or symbols if (node.expression.kind == ts.SyntaxKind.PropertyAccessExpression) { const t = checker.getTypeAtLocation(node.expression.expression); // List if (checker.isArrayType(t)) { switch (node.expression.name.escapedText) { case "map": if (node.arguments.length !== 1) throw "Can't handle this map call"; return `List.map ${handleNode(node.arguments[0])} ${handleNode( node.expression.expression )}`; case "filter": if (node.arguments.length !== 1) throw "Can't handle this filter call"; return `List.filter ${forceCastToBool( node.arguments[0] )} (${handleNode(node.expression.expression)})`; } } } return `${handleNode(node.expression)} ${node.arguments .map(handleNode) .join(" ")}`; }; const forceCastToBool = (node) => { let t; if ( node.kind === ts.SyntaxKind.ArrowFunction && !checker.isTypeAssignableTo( (t = checker.getTypeAtLocation(node.body)), checker.getBooleanType() ) ) { if (checker.isTypeAssignableTo(t, checker.getNumberType())) return `(\\${node.parameters.map(handleNode).join(" ")} -> ${handleNode( node.body )} /= 0)`; } return handleNode(node); }; return handleNode; }37:[] 32:{"id":"72539d518d6456ef","slug":"typescript-subset-elm","title":"TypeScript (subset) -> Elm","thumbnail":"e2f38b07a8629437c2abbc5ec004266d63f7dc1d0c7306371e6a373f06ac4817","access_level":"public","create_time":"$D2022-10-07T16:00:16.552Z","update_time":"$D2024-10-16T11:52:59.673Z","view_time":null,"first_public_time":"$D2022-10-10T12:53:44.923Z","has_unpublished_edits":null,"fork":false,"stars":1,"starred":false,"owner":{"type":"team","id":"a2f700b6ce27b844","login":"gampleman","name":"Jakub Hampl","avatar_url":"https://avatars-next.observableusercontent.com/6ee048ed02abfd79e76f2f9dd7c7e8658c47b116d846f2f9ca8814ecdde18ffc","tier":"starter_2024"},"version":388,"publish_version":null,"role":null,"authored":false,"authors":[{"type":"individual","id":"34d15c3b1cc754ed","login":"gampleman","name":"Jakub Hampl","avatar_url":"https://avatars-next.observableusercontent.com/6ee048ed02abfd79e76f2f9dd7c7e8658c47b116d846f2f9ca8814ecdde18ffc","tier":null}],"members":[{"type":"individual","id":"34d15c3b1cc754ed","login":"gampleman","name":"Jakub Hampl","avatar_url":"https://avatars-next.observableusercontent.com/6ee048ed02abfd79e76f2f9dd7c7e8658c47b116d846f2f9ca8814ecdde18ffc","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":1,"collection":null,"type":"notebook","body":{"title":"TypeScript (subset) -> Elm","cells":[{"id":0,"value":"# TypeScript (subset) -> Elm","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":197,"value":"

\n\n

\n\n${md`\n### input.ts\n\n\\`\\`\\`typescript\n${input}\n\\`\\`\\`\n`}\n\n \n

\n\n\n

\n${md`\n### Output.elm\n\n\\`\\`\\`elm\n${output}\n\\`\\`\\`\n`}\n \n

\n\n

","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":18,"value":"$34","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":92,"value":"output = {\n for (const sourceFile of program.getSourceFiles()) {\n if (!sourceFile.isDeclarationFile) {\n return handleNode(sourceFile);\n }\n }\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":52,"value":"ts = require(\"typescript@5.6.3/lib/typescript.js\").catch(() => window[\"ts\"])","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":382,"value":"bfs = require(\"browserfs@1.4.3/dist/browserfs.js\")","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":78,"value":"fs = bfs.BFSRequire(\"fs\")","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":386,"value":"path = bfs.BFSRequire(\"process\")","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":55,"value":"$35","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":96,"value":"checker = program.getTypeChecker()","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":5,"value":"$36","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":235,"value":"indent = (s) => \" \" + s.split(\"\\n\").join(\"\\n \")","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W37","stdlib":"1","titling":"auto"}} 33:"$32:body"