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| -rw-r--r-- | main.js | 341 |
1 files changed, 341 insertions, 0 deletions
@@ -0,0 +1,341 @@ +/* the clickbait headline programming language */ + +const prog = ` +DISCOVER HOW TO factorial WITH n +WE SAID + WHAT IF n IS ACTUALLY 0 + WE SAID + SHOCKING DEVELOPMENT 1 + LIES! WE SAID + SHOCKING DEVELOPMENT MULTIPLY n, factorial OF (n) + END OF STORY +END OF STORY + +EXPERTS CLAIM result TO BE factorial OF (10) +YOU WON'T WANT TO MISS 'RESULT IS' +YOU WON'T WANT TO MISS result + +PLEASE LIKE AND SUBSCRIBE +` + +/* tokenizer */ + +/** + * Reads in char or word chunks + */ +class Reader { + constructor(str, base = '') { + this.base = base; + this.i = 0; + this.str = str; + } + peek() { + return this.str[this.i]; + } + next() { + return this.str[this.i++]; + } + hasNext() { + return this.str[this.i] !== undefined; + } + backstep() { + this.i--; + } + readUntil(pred) { + let result = this.base.slice(); + while (this.hasNext() && !pred(this.peek())) { + result += this.next(); + } + return result; + } + dropWhitespace() { + this.readUntil(c => !!c.trim()); + } + expect(tok) { + const next = this.next(); + if (next !== tok) { + throw new Error(`Parsing error: expected ${tok}, got ${next}`); + } + } +} + +/** + * Split into words for easier tokenization + * with keywords. + */ +class Wordifier { + constructor(str) { + this.reader = new Reader(prog); + this.tokens = []; + } + wordify() { + if (this.tokens.length) return this.tokens; + + while (this.reader.hasNext()) { + const next = this.reader.next(); + switch (next) { + case '(': { + this.tokens.push('('); + break; + } + case ')': { + this.tokens.push(')'); + break; + } + case ',': { + this.tokens.push(','); + break; + } + case '"': + case "'": { + this.wordifyString(next); + break; + } + default: { + // read until WS + this.reader.backstep(); + this.tokens.push(this.reader.readUntil(c => { + return !c.trim() || ['(', ')', ','].includes(c) + })); + } + } + this.reader.dropWhitespace(); + } + return this.tokens.slice(1); + } + wordifyString(endChar) { + let acc = ''; + acc += this.reader.readUntil(c => c == endChar); + while (acc.endsWith('\\') || !this.reader.hasNext()) { + acc += this.reader.readUntil(c => c != endChar); + } + this.reader.next(); // throw away closing char + this.tokens.push('"' + acc); + } +} + +const T = { + LParen: Symbol('LParen'), + RParen: Symbol('RParen'), + Comma: Symbol('Comma'), + DiscoverHowTo: Symbol('DiscoverHowTo'), + With: Symbol('With'), + Of: Symbol('Of'), + WeSaid: Symbol('WeSaid'), + WhatIf: Symbol('WhatIf'), + LiesBang: Symbol('LiesBang'), + EndOfStory: Symbol('EndOfStory'), + ExpertsClaim: Symbol('ExpertsClaim'), + ToBe: Symbol('ToBe'), + YouWontWantToMiss: Symbol('YouWontWantToMiss'), + IsActually: Symbol('IsActually'), + And: Symbol('And'), + or: Symbol('or'), + Add: Symbol('Add'), + Subtract: Symbol('Subtract'), + Multiply: Symbol('Multiply'), + Divide: Symbol('Divide'), + Modulo: Symbol('Modulo'), + Beats: Symbol('Beats'), // > + SmallerThan: Symbol('SmallerThan'), // < + ShockingDevelopment: Symbol('ShockingDevelopment'), + PleaseLikeAndSubscribe: Symbol('PleaseLikeAndSubscribe'), + StayTuned: Symbol('StayTuned'), + Unexpectedly: Symbol('Unexpectedly'), + TotallyRight: Symbol('TotallyRight'), + CompletelyWrong: Symbol('CompletelyWrong'), +} + +class Tokenizer { + constructor(prog) { + this.reader = new Reader(new Wordifier(prog).wordify(), []); + this.tokens = []; + } + tokenize() { + if (this.tokens.length) return this.tokens; + + while (this.reader.hasNext()) { + const next = this.reader.next(); + switch (next) { + case 'DISCOVER': { + this.reader.expect('HOW'); + this.reader.expect('TO'); + this.tokens.push(T.DiscoverHowTo); + break; + } + case 'WITH': { + this.tokens.push(T.With); + break; + } + case 'OF': { + this.tokens.push(T.Of); + break; + } + case 'WE': { + this.reader.expect('SAID'); + this.tokens.push(T.WeSaid); + break; + } + case 'WHAT': { + this.reader.expect('IF'); + this.tokens.push(T.WhatIf); + break; + } + case 'LIES!': { + this.tokens.push(T.LiesBang); + break; + } + case 'END': { + this.reader.expect('OF'); + this.reader.expect('STORY'); + this.tokens.push(T.EndOfStory); + break; + } + case 'EXPERTS': { + this.reader.expect('CLAIM'); + this.tokens.push(T.ExpertsClaim); + break; + } + case 'TO': { + this.reader.expect('BE'); + this.tokens.push(T.ToBe); + break; + } + case 'YOU': { + this.reader.expect('WON\'T'); + this.reader.expect('WANT'); + this.reader.expect('TO'); + this.reader.expect('MISS'); + this.tokens.push(T.YouWontWantToMiss); + break; + } + case 'IS': { + this.reader.expect('ACTUALLY'); + this.tokens.push(T.IsActually); + break; + } + case 'AND': { + this.tokens.push(T.And); + break; + } + case 'OR': { + this.tokens.push(T.Or); + break; + } + case 'ADD': { + this.tokens.push(T.Add); + break; + } + case 'SUBTRACT': { + this.tokens.push(T.Subtract); + break; + } + case 'MULTIPLY': { + this.tokens.push(T.Multiply); + break; + } + case 'DIVIDE': { + this.tokens.push(T.Divide); + break; + } + case 'MODULO': { + this.tokens.push(T.Modulo); + break; + } + case 'BEATS': { + this.tokens.push(T.Beats); + break; + } + case 'SMALLER': { + this.reader.expect('THAN'); + this.tokens.push(T.SmallerThan); + break; + } + case 'SHOCKING': { + this.reader.expect('DEVELOPMENT'); + this.tokens.push(T.ShockingDevelopment); + break; + } + case 'PLEASE': { + this.reader.expect('LIKE'); + this.reader.expect('AND'); + this.reader.expect('SUBSCRIBE'); + this.tokens.push(T.PleaseLikeAndSubscribe); + break; + } + case 'STAY': { + this.reader.expect('TUNED'); + this.tokens.push(T.StayTuned); + break; + } + case 'UNEXPECTEDLY': { + this.tokens.push(T.Unexpectedly); + break; + } + case 'TOTALLY': { + this.reader.expect('RIGHT'); + this.tokens.push(T.TotallyRight); + break; + } + case 'COMPLETELY': { + this.reader.expect('WRONG'); + this.tokens.push(T.CompletelyWrong); + break; + } + case '(': { + this.tokens.push(T.LParen); + break; + } + case ')': { + this.tokens.push(T.RParen); + break; + } + case ',': { + this.tokens.push(T.Comma); + break; + } + default: { + if (!isNaN(parseFloat(next))) { + // number literal + this.tokens.push(parseFloat(next)); + } else { + // string or varname + this.tokens.push(next); + } + } + } + } + return this.tokens; + } +} + +function tokenize(prog) { + const reader = new Reader(prog); +} + +/* parser */ + +const N = { + NumberLiteral: Symbol('NumberLiteral'), + StringLiteral: Symbol('StringLiteral'), + FnLiteral: Symbol('FnLiteral'), + FnCall: Symbol('FnCall'), + Ident: Symbol('Ident'), + BinaryOp: Symbol('BinaryOp'), + IfExpr: Symbol('IfExpr'), + ExprList: Symbol('ExprList'), + // etc +} + +/* executor (tree walk) */ + +class Environment { + constructor(nodes) { + + } +} + +const tokens = new Tokenizer(prog).tokenize(); +console.log(tokens); + +const reader = new Reader("test of this"); |