Hack Club is running a programming language jam from June 08 - 29, where you'll get to hack on and ship a programming language in the span of three weeks and possibly win a chance to get a signed copy of Crafting Interpreters. Sign up here before June 07!
High schooler? Get stickers!
Table of contents
Orpheus writes a lexer
Now Orpheus fires up the computer our mysterious sender has so graciously included. It's kind of like an actual computer, except mini. Very small.
Wait, she thinks. I'm forgetting something. She swings by the kitchen to pick up some tea. You can't forget the tea. Ambiance is rather important.
So it turns out that the first step to writing a language is to write a lexer. That's a funny word, but it just represents a tool that divides a language into chunks. These chunks are called tokens.
Orpheus thinks this is kind of like speaking English, or Dinoese. You can divide a sentence into tokens, after all.
See? Tokens. Orpheus collects a lot of tokens, actually. Anyways, the point is that you can divide a sentence into multiple chunks that describe the structure of the sentence. It's even easier to do that for a programming language because the syntax is, well, so much easier to describe. No extra edge cases like there are in the English language.
Orpheus picks up the letter and looks at the first program again. How does one go about dividing this language into tokens? Well, it's quite helpful to draw out the important chunks. Luckily, Orpheus already has notes for this something, if she can still find them among her pile of other assorted papers. She's got a really bad habit of always having a bunch of papers on her desk.
Found it!
There! That makes a lot more sense, hopefully. These are some of the different kinds of tokens we can represent. So how do we write code to represent this? Well, that's what Orpheus is going to do right now, in lexer.js:
export const TOKENS = {
LeftParen: 'LeftParen',
RightParen: 'RightParen',
LeftBrace: 'LeftBrace',
RightBrace: 'RightBrace',
LeftBracket: 'LeftBracket',
RightBracket: 'RightBracket',
Period: 'Period',
Comma: 'Comma',
Colon: 'Colon',
Keyword: 'Keyword',
Identifier: 'Identifier',
String: 'String',
Number: 'Number',
Or: 'Or',
Not: 'Not',
And: 'And',
Equiv: 'Equiv',
NotEquiv: 'NotEquiv',
Gt: 'Gt',
Gte: 'Gte',
Lt: 'Lt',
Lte: 'Lte',
Plus: 'Plus',
Minus: 'Minus',
Asterisk: 'Asterisk',
Slash: 'Slash',
EOF: 'EOF'
}
export class Token {
constructor(type, value, content, line, column) {
this.type = type // Any value in TOKENS
this.value = value
this.content = content
this.line = line
this.column = column
}
toString() {
return this.value
}
}
Coolio. Now that we have tokens, how do we go about creating a lexer? That's a bit of a harder thing to do. We know this:
So we know we take a program, pass it into a lexer, and we get tokens out. We just need to figure out what's in that black box exactly.
Now, the idea is to read every character one by one. If a set of characters form a token that we can recognize, then we add it to a list of tokens we have.
Sounds pretty simple, innit? Woah there. Where'd you get a British accent out of the blue from, Orpheus?
Anyways. This means we need some extra useful functions to read the characters and determine when we can combine a bunch of them together. Let's start by just creating a class for our lexer:
import { EaselError } from './stdlib.js'
export class Lexer {
constructor(program) {
this.program = program
this.tokens = []
this.current = 0
this.line = 1
this.column = 0
}
error(msg) {
throw new EaselError(`Error on ${this.line}:${this.column}: ${msg}`)
}
}
What we really need is to start reading each character in our program. Let's do that with scanTokens:
class Lexer {
// ...
scanTokens() {
while (this.peek() !== '\0') this.scanToken()
this.tokens.push(new Token(TOKENS.EOF, null, null, this.line, this.column))
return this.tokens
}
}
All scanToken does is go over every character and run a method called scanToken, while we haven't reached the end of the program (see the sidebar for more info!). Now, before we get to scanToken, we've got to take a look at peek. This is the first of our useful utility functions for peeking ahead and checking what the next character is:
class Lexer {
// ...
peek() {
if (this.current >= this.program.length) return '\0'
return this.program[this.current]
}
scanTokens() {
// ...
}
}
Cool! Now we can see what the next character is. The most logical step, now that we can peek at the next character, is to actually move to the next character. Let's call this advancing. It'll look pretty similar to peek(), except we'll update what character we're on rather than just looking ahead:
advance() {
if (this.current >= this.program.length) return '\0'
this.column++
return this.program[this.current++]
}
scanToken
Ok. Let's start writing this scanToken method:
class Lexer {
// ...
scanToken() {
const char = this.advance()
switch (char) {
case '(': {
return this.tokens.push(
new Token(TOKENS.LeftParen, '(', '(', this.line, this.column)
)
}
case ')': {
return this.tokens.push(
new Token(TOKENS.RightParen, ')', ')', this.line, this.column)
)
}
case '{': {
return this.tokens.push(
new Token(TOKENS.LeftBrace, '{', '{', this.line, this.column)
)
}
case '}': {
return this.tokens.push(
new Token(TOKENS.RightBrace, '}', '}', this.line, this.column)
)
}
case '[': {
return this.tokens.push(
new Token(TOKENS.LeftBracket, '[', '[', this.line, this.column)
)
}
case ']': {
return this.tokens.push(
new Token(TOKENS.RightBracket, ']', ']', this.line, this.column)
)
}
case '.': {
return this.tokens.push(
new Token(TOKENS.Period, '.', '.', this.line, this.column)
)
}
case ',': {
return this.tokens.push(
new Token(TOKENS.Comma, ',', ',', this.line, this.column)
)
}
case ':': {
return this.tokens.push(
new Token(TOKENS.Colon, ':', ':', this.line, this.column)
)
}
case '+': {
return this.tokens.push(
new Token(TOKENS.Plus, '+', '+', this.line, this.column)
)
}
case '-': {
return this.tokens.push(
new Token(TOKENS.Minus, '-', '-', this.line, this.column)
)
}
case '*': {
return this.tokens.push(
new Token(TOKENS.Asterisk, '*', '*', this.line, this.column)
)
}
case '/': {
return this.tokens.push(
new Token(TOKENS.Slash, '/', '/', this.line, this.column)
)
}
}
}
scanTokens() {
// ...
}
}
Perfect. Let's take a look at our tokens. LeftParen, check. RightParen, check. LeftBrace, check. RightBrace, check. LeftBracket, check. RightBracket, check. Period, check. Comma, check. Colon, check. Keyword, Identifier - we'll get to those later.
Strings! Let's add a case to take care of strings now. The idea is that we'll keep going until we reach a matching closing quote. That looks something like:
case "'":
case '"': {
// String
let string = []
while (this.peek() !== char) {
string.push(this.advance())
if (this.peek() === '\0')
// String wasn't closed
this.error('Unexpected end of file; expected a closing quote')
}
this.advance() // Skip closing quote
string = string.join('')
return this.tokens.push(
new Token(TOKENS.String, string, string, this.line, this.column)
)
}
We remember to deal with both quotes and if we reach the end of the file without finding a closing quote, that's a problem and we make sure to let the user know. Pretty solid, eh?
Cool. String, check. Number, Boolean - we'll get to those later. Or - let's work on Or! The operator has two pipe characters. That means we need to see the next-next character. A smarter way of doing this, actually, is to introduce a new helper method, called match(), that will try to move to the next character but only if it matches up with what we expect the next character to be:
match(char) {
if (this.peek() === char) return this.advance()
return false
}
That packs a double suckerpunch like so:
case '|': {
if (this.match('|'))
return this.tokens.push(
new Token(TOKENS.Or, '||', '||', this.line, this.column)
)
}
Pretty ingenious. We can take care of a bunch of other tokens using this strat too:
case '>': {
if (this.match('='))
return this.tokens.push(
new Token(TOKENS.Gte, '>=', '>=', this.line, this.column)
)
return this.tokens.push(
new Token(TOKENS.Gt, '>', '>', this.line, this.column)
)
}
case '<': {
if (this.match('='))
return this.tokens.push(
new Token(TOKENS.Lte, '<=', '<=', this.line, this.column)
)
return this.tokens.push(
new Token(TOKENS.Lt, '<', '<', this.line, this.column)
)
}
case '=': {
if (this.match('='))
return this.tokens.push(
new Token(TOKENS.Equiv, '==', '==', this.line, this.column)
)
}
case '&': {
if (this.match('&'))
return this.tokens.push(
new Token(TOKENS.And, '&&', '&&', this.line, this.column)
)
}
case '!': {
if (this.match('='))
return this.tokens.push(
new Token(TOKENS.NotEquiv, '!=', '!=', this.line, this.column)
)
return this.tokens.push(
new Token(TOKENS.Not, '!', '!', this.line, this.column)
)
}
That takes care of most of our possible tokens.
Finally. What if our character doesn't match any of these tokens? In that case, a set of characters might match up to an appropriate token - I'm thinking either a Number, Identifier, or Keyword. Let's deal with all of this in our default branch!
default:
// Let's fill this in!
Ok. Let's fill this in one by one with all the cases. How about numbers first? The criteria is easy: numbers are made up of numeric digits. Because we don't distinguish between ints and floats, a number could also include a singular period. Thus, we can do something like this:
default:
if (isNumber(char)) {
let number = [char]
while (isNumber(this.peek()) || (this.peek() === "." && !number.includes(".")))
number.push(this.advance())
number = number.join("")
return this.tokens.push(
new Token(
TOKENS.Number,
number,
Number(number),
this.line,
this.column
)
)
}
Our first number is our current character. Then, we keep eating the next character while it's a number or it's the first period we encounter. When we finally hit a character that doesn't meet either criteria, we have a Number token!
This relies on a helper function we don't have yet, isNumber. Let's nest that function inside scanToken():
const isNumber = char => char >= '0' && char <= '9'
Ok, the next obvious next step is to read a string without spaces in. That's what identifiers and keywords are all about - the only extra thing we'll need to do for keywords is check if they belong to a list of reserved keywords. Let's set up that list first at the top of lexer.js:
export const KEYWORDS = {
prepare: 'prepare',
as: 'as', // Variables
brush: 'brush',
prep: 'prep',
has: 'has', // Structs
sketch: 'sketch',
needs: 'needs',
finished: 'finished', // Functions
loop: 'loop',
through: 'through',
while: 'while', // Loops
if: 'if',
elif: 'elif',
else: 'else' // Conditionals
}
Now that we've got that, we can deal with identifiers and keywords:
if (isNumber(char)) {
// ...
} else if (isChar(char)) {
// Identifier or keyword
let identifier = [char]
while (isAlphanumeric(this.peek())) identifier.push(this.advance())
identifier = identifier.join('')
if (Object.keys(KEYWORDS).includes(identifier))
return this.tokens.push(
new Token(
TOKENS.Keyword,
identifier,
KEYWORDS[identifier],
this.line,
this.column
)
)
else if (identifier === 'true' || identifier === 'false')
return this.tokens.push(
new Token(TOKENS.Boolean, identifier, identifier === 'true')
)
return this.tokens.push(
new Token(TOKENS.Identifier, identifier, identifier, this.line, this.column)
)
} else this.error('Unexpected symbol ' + char)
Notice how it's not an else statement but an else-if statement that checks if the current character meets the criteria of isChar(). We don't want to accept all characters for our identifiers and keywords - for example, variable names like ~testVar shouldn't be allowed, and so we have a final else statement that will throw an error if we encounter an unexpected symbol. Let's see what we can accept in isChar():
const isChar = char =>
(char >= 'A' && char <= 'Z') || (char >= 'a' && char <= 'z') || char === '_'
Inside the else-if statement though, we use a different function, isAlphanumeric, since our identifiers can have numbers in them (just not the first character!):
const isAlphanumeric = char => isNumber(char) || isChar(char)
Awesome. This is all that we really need for our lexer, but there are just two cases we need to deal with: comments and whitespace. Since Easel doesn't rely on whitespace, it makes sense to just ignore any characters that are whitespace-related. Let's deal with these two cases:
case '~': {
// Comments
while (this.peek() !== '\n' && this.peek() !== '\0') this.advance()
return
}
case ' ':
case '\r': {
// Ignore whitespace
return
}
case '\n': {
// Also ignore, but update line
this.line++
this.column = 0
return
}
Ok! Let's test out our lexer now! In easel.js:
import { EaselError } from './stdlib.js'
import { Lexer } from './lexer.js'
// ...
const program = await readFile(location)
const lexer = new Lexer(program)
try {
lexer.scanTokens()
} catch (err) {
console.log(err)
process.exit(1)
} finally {
if (debug) await writeFile('tokens.json', JSON.stringify(lexer.tokens, null, 2))
}
Run node easel.js test.easel --dbg and you'll get this in tokens.json:
[
{
"type": "Keyword",
"value": "prepare",
"content": "prepare",
"line": 1,
"column": 8
},
{
"type": "Identifier",
"value": "rows",
"content": "rows",
"line": 1,
"column": 13
},
{
"type": "Keyword",
"value": "as",
"content": "as",
"line": 1,
"column": 16
},
{ "type": "Number", "value": "50", "content": 50, "line": 1, "column": 19 },
{
"type": "Keyword",
"value": "prepare",
"content": "prepare",
"line": 2,
"column": 7
},
{
"type": "Identifier",
"value": "cols",
"content": "cols",
"line": 2,
"column": 12
},
{
"type": "Keyword",
"value": "as",
"content": "as",
"line": 2,
"column": 15
},
{ "type": "Number", "value": "20", "content": 20, "line": 2, "column": 18 },
{
"type": "Keyword",
"value": "brush",
"content": "brush",
"line": 4,
"column": 5
},
{
"type": "Identifier",
"value": "Cell",
"content": "Cell",
"line": 4,
"column": 10
},
{
"type": "Keyword",
"value": "has",
"content": "has",
"line": 4,
"column": 14
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 4,
"column": 16
},
{
"type": "Identifier",
"value": "x",
"content": "x",
"line": 4,
"column": 18
},
{ "type": "Comma", "value": ",", "content": ",", "line": 4, "column": 19 },
{
"type": "Identifier",
"value": "y",
"content": "y",
"line": 4,
"column": 21
},
{ "type": "Comma", "value": ",", "content": ",", "line": 4, "column": 22 },
{
"type": "Identifier",
"value": "live",
"content": "live",
"line": 4,
"column": 27
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 4,
"column": 29
},
{
"type": "Keyword",
"value": "sketch",
"content": "sketch",
"line": 7,
"column": 6
},
{
"type": "Identifier",
"value": "seed",
"content": "seed",
"line": 7,
"column": 11
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 7,
"column": 13
},
{
"type": "Keyword",
"value": "prepare",
"content": "prepare",
"line": 8,
"column": 9
},
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 8,
"column": 15
},
{
"type": "Keyword",
"value": "as",
"content": "as",
"line": 8,
"column": 18
},
{
"type": "LeftBracket",
"value": "[",
"content": "[",
"line": 8,
"column": 20
},
{
"type": "RightBracket",
"value": "]",
"content": "]",
"line": 8,
"column": 21
},
{
"type": "Keyword",
"value": "loop",
"content": "loop",
"line": 10,
"column": 6
},
{
"type": "Identifier",
"value": "x",
"content": "x",
"line": 10,
"column": 8
},
{
"type": "Keyword",
"value": "through",
"content": "through",
"line": 10,
"column": 16
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 10,
"column": 18
},
{ "type": "Number", "value": "0", "content": 0, "line": 10, "column": 19 },
{ "type": "Comma", "value": ",", "content": ",", "line": 10, "column": 20 },
{
"type": "Identifier",
"value": "rows",
"content": "rows",
"line": 10,
"column": 25
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 10,
"column": 26
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 10,
"column": 28
},
{
"type": "Keyword",
"value": "loop",
"content": "loop",
"line": 11,
"column": 8
},
{
"type": "Identifier",
"value": "y",
"content": "y",
"line": 11,
"column": 10
},
{
"type": "Keyword",
"value": "through",
"content": "through",
"line": 11,
"column": 18
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 11,
"column": 20
},
{ "type": "Number", "value": "0", "content": 0, "line": 11, "column": 21 },
{ "type": "Comma", "value": ",", "content": ",", "line": 11, "column": 22 },
{
"type": "Identifier",
"value": "cols",
"content": "cols",
"line": 11,
"column": 27
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 11,
"column": 28
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 11,
"column": 30
},
{
"type": "Keyword",
"value": "prepare",
"content": "prepare",
"line": 12,
"column": 13
},
{
"type": "Identifier",
"value": "live",
"content": "live",
"line": 12,
"column": 18
},
{
"type": "Keyword",
"value": "as",
"content": "as",
"line": 12,
"column": 21
},
{ "type": "Boolean", "value": "false", "content": false },
{
"type": "Keyword",
"value": "prepare",
"content": "prepare",
"line": 13,
"column": 13
},
{
"type": "Identifier",
"value": "chance",
"content": "chance",
"line": 13,
"column": 20
},
{
"type": "Keyword",
"value": "as",
"content": "as",
"line": 13,
"column": 23
},
{
"type": "Identifier",
"value": "random",
"content": "random",
"line": 13,
"column": 30
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 13,
"column": 31
},
{ "type": "Number", "value": "0", "content": 0, "line": 13, "column": 32 },
{ "type": "Comma", "value": ",", "content": ",", "line": 13, "column": 33 },
{
"type": "Number",
"value": "100",
"content": 100,
"line": 13,
"column": 37
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 13,
"column": 38
},
{
"type": "Keyword",
"value": "if",
"content": "if",
"line": 14,
"column": 8
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 14,
"column": 10
},
{
"type": "Identifier",
"value": "chance",
"content": "chance",
"line": 14,
"column": 16
},
{ "type": "Lt", "value": "<", "content": "<", "line": 14, "column": 18 },
{ "type": "Number", "value": "20", "content": 20, "line": 14, "column": 21 },
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 14,
"column": 22
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 14,
"column": 24
},
{
"type": "Keyword",
"value": "prepare",
"content": "prepare",
"line": 15,
"column": 15
},
{
"type": "Identifier",
"value": "live",
"content": "live",
"line": 15,
"column": 20
},
{
"type": "Keyword",
"value": "as",
"content": "as",
"line": 15,
"column": 23
},
{ "type": "Boolean", "value": "true", "content": true },
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 16,
"column": 7
},
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 17,
"column": 11
},
{ "type": "Period", "value": ".", "content": ".", "line": 17, "column": 12 },
{
"type": "Identifier",
"value": "add",
"content": "add",
"line": 17,
"column": 15
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 17,
"column": 16
},
{
"type": "Keyword",
"value": "prep",
"content": "prep",
"line": 17,
"column": 20
},
{
"type": "Identifier",
"value": "Cell",
"content": "Cell",
"line": 17,
"column": 25
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 17,
"column": 26
},
{
"type": "Identifier",
"value": "x",
"content": "x",
"line": 17,
"column": 27
},
{ "type": "Colon", "value": ":", "content": ":", "line": 17, "column": 28 },
{
"type": "Identifier",
"value": "x",
"content": "x",
"line": 17,
"column": 30
},
{ "type": "Comma", "value": ",", "content": ",", "line": 17, "column": 31 },
{
"type": "Identifier",
"value": "y",
"content": "y",
"line": 17,
"column": 33
},
{ "type": "Colon", "value": ":", "content": ":", "line": 17, "column": 34 },
{
"type": "Identifier",
"value": "y",
"content": "y",
"line": 17,
"column": 36
},
{ "type": "Comma", "value": ",", "content": ",", "line": 17, "column": 37 },
{
"type": "Identifier",
"value": "live",
"content": "live",
"line": 17,
"column": 42
},
{ "type": "Colon", "value": ":", "content": ":", "line": 17, "column": 43 },
{
"type": "Identifier",
"value": "live",
"content": "live",
"line": 17,
"column": 48
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 17,
"column": 49
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 17,
"column": 50
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 18,
"column": 5
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 19,
"column": 3
},
{
"type": "Keyword",
"value": "finished",
"content": "finished",
"line": 20,
"column": 10
},
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 20,
"column": 16
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 21,
"column": 1
},
{
"type": "Keyword",
"value": "prepare",
"content": "prepare",
"line": 23,
"column": 7
},
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 23,
"column": 13
},
{
"type": "Keyword",
"value": "as",
"content": "as",
"line": 23,
"column": 16
},
{
"type": "Identifier",
"value": "seed",
"content": "seed",
"line": 23,
"column": 21
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 23,
"column": 22
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 23,
"column": 23
},
{
"type": "Keyword",
"value": "sketch",
"content": "sketch",
"line": 25,
"column": 6
},
{
"type": "Identifier",
"value": "getNeighbors",
"content": "getNeighbors",
"line": 25,
"column": 19
},
{
"type": "Keyword",
"value": "needs",
"content": "needs",
"line": 25,
"column": 25
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 25,
"column": 27
},
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 25,
"column": 32
},
{ "type": "Comma", "value": ",", "content": ",", "line": 25, "column": 33 },
{
"type": "Identifier",
"value": "index",
"content": "index",
"line": 25,
"column": 39
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 25,
"column": 40
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 25,
"column": 42
},
{
"type": "Keyword",
"value": "prepare",
"content": "prepare",
"line": 27,
"column": 9
},
{
"type": "Identifier",
"value": "neighbors",
"content": "neighbors",
"line": 27,
"column": 19
},
{
"type": "Keyword",
"value": "as",
"content": "as",
"line": 27,
"column": 22
},
{
"type": "LeftBracket",
"value": "[",
"content": "[",
"line": 27,
"column": 24
},
{
"type": "RightBracket",
"value": "]",
"content": "]",
"line": 27,
"column": 25
},
{
"type": "Keyword",
"value": "if",
"content": "if",
"line": 30,
"column": 4
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 30,
"column": 6
},
{
"type": "Identifier",
"value": "index",
"content": "index",
"line": 30,
"column": 11
},
{ "type": "Minus", "value": "-", "content": "-", "line": 30, "column": 13 },
{
"type": "Identifier",
"value": "rows",
"content": "rows",
"line": 30,
"column": 18
},
{ "type": "Minus", "value": "-", "content": "-", "line": 30, "column": 20 },
{ "type": "Number", "value": "1", "content": 1, "line": 30, "column": 22 },
{ "type": "Gt", "value": ">", "content": ">", "line": 30, "column": 24 },
{ "type": "Number", "value": "0", "content": 0, "line": 30, "column": 26 },
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 30,
"column": 27
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 30,
"column": 29
},
{
"type": "Identifier",
"value": "neighbors",
"content": "neighbors",
"line": 31,
"column": 13
},
{ "type": "Period", "value": ".", "content": ".", "line": 31, "column": 14 },
{
"type": "Identifier",
"value": "add",
"content": "add",
"line": 31,
"column": 17
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 31,
"column": 18
},
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 31,
"column": 23
},
{
"type": "LeftBracket",
"value": "[",
"content": "[",
"line": 31,
"column": 24
},
{
"type": "Identifier",
"value": "index",
"content": "index",
"line": 31,
"column": 29
},
{ "type": "Minus", "value": "-", "content": "-", "line": 31, "column": 31 },
{
"type": "Identifier",
"value": "rows",
"content": "rows",
"line": 31,
"column": 36
},
{ "type": "Minus", "value": "-", "content": "-", "line": 31, "column": 38 },
{ "type": "Number", "value": "1", "content": 1, "line": 31, "column": 40 },
{
"type": "RightBracket",
"value": "]",
"content": "]",
"line": 31,
"column": 41
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 31,
"column": 42
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 32,
"column": 3
},
{
"type": "Keyword",
"value": "if",
"content": "if",
"line": 33,
"column": 4
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 33,
"column": 6
},
{
"type": "Identifier",
"value": "index",
"content": "index",
"line": 33,
"column": 11
},
{ "type": "Minus", "value": "-", "content": "-", "line": 33, "column": 13 },
{
"type": "Identifier",
"value": "rows",
"content": "rows",
"line": 33,
"column": 18
},
{ "type": "Gt", "value": ">", "content": ">", "line": 33, "column": 20 },
{ "type": "Number", "value": "0", "content": 0, "line": 33, "column": 22 },
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 33,
"column": 23
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 33,
"column": 25
},
{
"type": "Identifier",
"value": "neighbors",
"content": "neighbors",
"line": 34,
"column": 13
},
{ "type": "Period", "value": ".", "content": ".", "line": 34, "column": 14 },
{
"type": "Identifier",
"value": "add",
"content": "add",
"line": 34,
"column": 17
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 34,
"column": 18
},
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 34,
"column": 23
},
{
"type": "LeftBracket",
"value": "[",
"content": "[",
"line": 34,
"column": 24
},
{
"type": "Identifier",
"value": "index",
"content": "index",
"line": 34,
"column": 29
},
{ "type": "Minus", "value": "-", "content": "-", "line": 34, "column": 31 },
{
"type": "Identifier",
"value": "rows",
"content": "rows",
"line": 34,
"column": 36
},
{
"type": "RightBracket",
"value": "]",
"content": "]",
"line": 34,
"column": 37
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 34,
"column": 38
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 35,
"column": 3
},
{
"type": "Keyword",
"value": "if",
"content": "if",
"line": 36,
"column": 4
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 36,
"column": 6
},
{
"type": "Identifier",
"value": "index",
"content": "index",
"line": 36,
"column": 11
},
{ "type": "Minus", "value": "-", "content": "-", "line": 36, "column": 13 },
{
"type": "Identifier",
"value": "rows",
"content": "rows",
"line": 36,
"column": 18
},
{ "type": "Plus", "value": "+", "content": "+", "line": 36, "column": 20 },
{ "type": "Number", "value": "1", "content": 1, "line": 36, "column": 22 },
{ "type": "Gt", "value": ">", "content": ">", "line": 36, "column": 24 },
{ "type": "Number", "value": "0", "content": 0, "line": 36, "column": 26 },
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 36,
"column": 27
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 36,
"column": 29
},
{
"type": "Identifier",
"value": "neighbors",
"content": "neighbors",
"line": 37,
"column": 13
},
{ "type": "Period", "value": ".", "content": ".", "line": 37, "column": 14 },
{
"type": "Identifier",
"value": "add",
"content": "add",
"line": 37,
"column": 17
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 37,
"column": 18
},
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 37,
"column": 23
},
{
"type": "LeftBracket",
"value": "[",
"content": "[",
"line": 37,
"column": 24
},
{
"type": "Identifier",
"value": "index",
"content": "index",
"line": 37,
"column": 29
},
{ "type": "Minus", "value": "-", "content": "-", "line": 37, "column": 31 },
{
"type": "Identifier",
"value": "rows",
"content": "rows",
"line": 37,
"column": 36
},
{ "type": "Plus", "value": "+", "content": "+", "line": 37, "column": 38 },
{ "type": "Number", "value": "1", "content": 1, "line": 37, "column": 40 },
{
"type": "RightBracket",
"value": "]",
"content": "]",
"line": 37,
"column": 41
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 37,
"column": 42
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 38,
"column": 3
},
{
"type": "Keyword",
"value": "if",
"content": "if",
"line": 39,
"column": 4
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 39,
"column": 6
},
{
"type": "Identifier",
"value": "index",
"content": "index",
"line": 39,
"column": 11
},
{ "type": "Gt", "value": ">", "content": ">", "line": 39, "column": 13 },
{ "type": "Number", "value": "0", "content": 0, "line": 39, "column": 15 },
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 39,
"column": 16
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 39,
"column": 18
},
{
"type": "Identifier",
"value": "neighbors",
"content": "neighbors",
"line": 40,
"column": 13
},
{ "type": "Period", "value": ".", "content": ".", "line": 40, "column": 14 },
{
"type": "Identifier",
"value": "add",
"content": "add",
"line": 40,
"column": 17
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 40,
"column": 18
},
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 40,
"column": 23
},
{
"type": "LeftBracket",
"value": "[",
"content": "[",
"line": 40,
"column": 24
},
{
"type": "Identifier",
"value": "index",
"content": "index",
"line": 40,
"column": 29
},
{ "type": "Minus", "value": "-", "content": "-", "line": 40, "column": 31 },
{ "type": "Number", "value": "1", "content": 1, "line": 40, "column": 33 },
{
"type": "RightBracket",
"value": "]",
"content": "]",
"line": 40,
"column": 34
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 40,
"column": 35
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 41,
"column": 3
},
{
"type": "Keyword",
"value": "if",
"content": "if",
"line": 42,
"column": 4
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 42,
"column": 6
},
{
"type": "Identifier",
"value": "index",
"content": "index",
"line": 42,
"column": 11
},
{ "type": "Lt", "value": "<", "content": "<", "line": 42, "column": 13 },
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 42,
"column": 19
},
{ "type": "Period", "value": ".", "content": ".", "line": 42, "column": 20 },
{
"type": "Identifier",
"value": "length",
"content": "length",
"line": 42,
"column": 26
},
{ "type": "Minus", "value": "-", "content": "-", "line": 42, "column": 28 },
{ "type": "Number", "value": "1", "content": 1, "line": 42, "column": 30 },
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 42,
"column": 31
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 42,
"column": 33
},
{
"type": "Identifier",
"value": "neighbors",
"content": "neighbors",
"line": 43,
"column": 13
},
{ "type": "Period", "value": ".", "content": ".", "line": 43, "column": 14 },
{
"type": "Identifier",
"value": "add",
"content": "add",
"line": 43,
"column": 17
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 43,
"column": 18
},
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 43,
"column": 23
},
{
"type": "LeftBracket",
"value": "[",
"content": "[",
"line": 43,
"column": 24
},
{
"type": "Identifier",
"value": "index",
"content": "index",
"line": 43,
"column": 29
},
{ "type": "Plus", "value": "+", "content": "+", "line": 43, "column": 31 },
{ "type": "Number", "value": "1", "content": 1, "line": 43, "column": 33 },
{
"type": "RightBracket",
"value": "]",
"content": "]",
"line": 43,
"column": 34
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 43,
"column": 35
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 44,
"column": 3
},
{
"type": "Keyword",
"value": "if",
"content": "if",
"line": 45,
"column": 4
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 45,
"column": 6
},
{
"type": "Identifier",
"value": "index",
"content": "index",
"line": 45,
"column": 11
},
{ "type": "Plus", "value": "+", "content": "+", "line": 45, "column": 13 },
{
"type": "Identifier",
"value": "rows",
"content": "rows",
"line": 45,
"column": 18
},
{ "type": "Minus", "value": "-", "content": "-", "line": 45, "column": 20 },
{ "type": "Number", "value": "1", "content": 1, "line": 45, "column": 22 },
{ "type": "Lt", "value": "<", "content": "<", "line": 45, "column": 24 },
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 45,
"column": 30
},
{ "type": "Period", "value": ".", "content": ".", "line": 45, "column": 31 },
{
"type": "Identifier",
"value": "length",
"content": "length",
"line": 45,
"column": 37
},
{ "type": "Minus", "value": "-", "content": "-", "line": 45, "column": 39 },
{ "type": "Number", "value": "1", "content": 1, "line": 45, "column": 41 },
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 45,
"column": 42
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 45,
"column": 44
},
{
"type": "Identifier",
"value": "neighbors",
"content": "neighbors",
"line": 46,
"column": 13
},
{ "type": "Period", "value": ".", "content": ".", "line": 46, "column": 14 },
{
"type": "Identifier",
"value": "add",
"content": "add",
"line": 46,
"column": 17
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 46,
"column": 18
},
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 46,
"column": 23
},
{
"type": "LeftBracket",
"value": "[",
"content": "[",
"line": 46,
"column": 24
},
{
"type": "Identifier",
"value": "index",
"content": "index",
"line": 46,
"column": 29
},
{ "type": "Plus", "value": "+", "content": "+", "line": 46, "column": 31 },
{
"type": "Identifier",
"value": "rows",
"content": "rows",
"line": 46,
"column": 36
},
{ "type": "Minus", "value": "-", "content": "-", "line": 46, "column": 38 },
{ "type": "Number", "value": "1", "content": 1, "line": 46, "column": 40 },
{
"type": "RightBracket",
"value": "]",
"content": "]",
"line": 46,
"column": 41
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 46,
"column": 42
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 47,
"column": 3
},
{
"type": "Keyword",
"value": "if",
"content": "if",
"line": 48,
"column": 4
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 48,
"column": 6
},
{
"type": "Identifier",
"value": "index",
"content": "index",
"line": 48,
"column": 11
},
{ "type": "Plus", "value": "+", "content": "+", "line": 48, "column": 13 },
{
"type": "Identifier",
"value": "rows",
"content": "rows",
"line": 48,
"column": 18
},
{ "type": "Lt", "value": "<", "content": "<", "line": 48, "column": 20 },
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 48,
"column": 26
},
{ "type": "Period", "value": ".", "content": ".", "line": 48, "column": 27 },
{
"type": "Identifier",
"value": "length",
"content": "length",
"line": 48,
"column": 33
},
{ "type": "Minus", "value": "-", "content": "-", "line": 48, "column": 35 },
{ "type": "Number", "value": "1", "content": 1, "line": 48, "column": 37 },
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 48,
"column": 38
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 48,
"column": 40
},
{
"type": "Identifier",
"value": "neighbors",
"content": "neighbors",
"line": 49,
"column": 13
},
{ "type": "Period", "value": ".", "content": ".", "line": 49, "column": 14 },
{
"type": "Identifier",
"value": "add",
"content": "add",
"line": 49,
"column": 17
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 49,
"column": 18
},
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 49,
"column": 23
},
{
"type": "LeftBracket",
"value": "[",
"content": "[",
"line": 49,
"column": 24
},
{
"type": "Identifier",
"value": "index",
"content": "index",
"line": 49,
"column": 29
},
{ "type": "Plus", "value": "+", "content": "+", "line": 49, "column": 31 },
{ "type": "Number", "value": "1", "content": 1, "line": 49, "column": 33 },
{
"type": "RightBracket",
"value": "]",
"content": "]",
"line": 49,
"column": 34
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 49,
"column": 35
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 50,
"column": 3
},
{
"type": "Keyword",
"value": "if",
"content": "if",
"line": 51,
"column": 4
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 51,
"column": 6
},
{
"type": "Identifier",
"value": "index",
"content": "index",
"line": 51,
"column": 11
},
{ "type": "Plus", "value": "+", "content": "+", "line": 51, "column": 13 },
{
"type": "Identifier",
"value": "rows",
"content": "rows",
"line": 51,
"column": 18
},
{ "type": "Plus", "value": "+", "content": "+", "line": 51, "column": 20 },
{ "type": "Number", "value": "1", "content": 1, "line": 51, "column": 22 },
{ "type": "Lt", "value": "<", "content": "<", "line": 51, "column": 24 },
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 51,
"column": 30
},
{ "type": "Period", "value": ".", "content": ".", "line": 51, "column": 31 },
{
"type": "Identifier",
"value": "length",
"content": "length",
"line": 51,
"column": 37
},
{ "type": "Minus", "value": "-", "content": "-", "line": 51, "column": 39 },
{ "type": "Number", "value": "1", "content": 1, "line": 51, "column": 41 },
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 51,
"column": 42
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 51,
"column": 44
},
{
"type": "Identifier",
"value": "neighbors",
"content": "neighbors",
"line": 52,
"column": 13
},
{ "type": "Period", "value": ".", "content": ".", "line": 52, "column": 14 },
{
"type": "Identifier",
"value": "add",
"content": "add",
"line": 52,
"column": 17
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 52,
"column": 18
},
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 52,
"column": 23
},
{
"type": "LeftBracket",
"value": "[",
"content": "[",
"line": 52,
"column": 24
},
{
"type": "Identifier",
"value": "index",
"content": "index",
"line": 52,
"column": 29
},
{ "type": "Plus", "value": "+", "content": "+", "line": 52, "column": 31 },
{
"type": "Identifier",
"value": "rows",
"content": "rows",
"line": 52,
"column": 36
},
{ "type": "Minus", "value": "-", "content": "-", "line": 52, "column": 38 },
{ "type": "Number", "value": "1", "content": 1, "line": 52, "column": 40 },
{
"type": "RightBracket",
"value": "]",
"content": "]",
"line": 52,
"column": 41
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 52,
"column": 42
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 53,
"column": 3
},
{
"type": "Keyword",
"value": "prepare",
"content": "prepare",
"line": 55,
"column": 9
},
{
"type": "Identifier",
"value": "alive",
"content": "alive",
"line": 55,
"column": 15
},
{
"type": "Keyword",
"value": "as",
"content": "as",
"line": 55,
"column": 18
},
{
"type": "LeftBracket",
"value": "[",
"content": "[",
"line": 55,
"column": 20
},
{
"type": "RightBracket",
"value": "]",
"content": "]",
"line": 55,
"column": 21
},
{
"type": "Keyword",
"value": "loop",
"content": "loop",
"line": 56,
"column": 6
},
{
"type": "Identifier",
"value": "i",
"content": "i",
"line": 56,
"column": 8
},
{
"type": "Keyword",
"value": "through",
"content": "through",
"line": 56,
"column": 16
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 56,
"column": 18
},
{ "type": "Number", "value": "0", "content": 0, "line": 56, "column": 19 },
{ "type": "Comma", "value": ",", "content": ",", "line": 56, "column": 20 },
{
"type": "Identifier",
"value": "neighbors",
"content": "neighbors",
"line": 56,
"column": 30
},
{ "type": "Period", "value": ".", "content": ".", "line": 56, "column": 31 },
{
"type": "Identifier",
"value": "length",
"content": "length",
"line": 56,
"column": 37
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 56,
"column": 38
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 56,
"column": 40
},
{
"type": "Keyword",
"value": "if",
"content": "if",
"line": 57,
"column": 6
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 57,
"column": 8
},
{
"type": "Identifier",
"value": "neighbors",
"content": "neighbors",
"line": 57,
"column": 17
},
{
"type": "LeftBracket",
"value": "[",
"content": "[",
"line": 57,
"column": 18
},
{
"type": "Identifier",
"value": "i",
"content": "i",
"line": 57,
"column": 19
},
{
"type": "RightBracket",
"value": "]",
"content": "]",
"line": 57,
"column": 20
},
{ "type": "Period", "value": ".", "content": ".", "line": 57, "column": 21 },
{
"type": "Identifier",
"value": "live",
"content": "live",
"line": 57,
"column": 25
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 57,
"column": 26
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 57,
"column": 28
},
{
"type": "Identifier",
"value": "alive",
"content": "alive",
"line": 58,
"column": 11
},
{ "type": "Period", "value": ".", "content": ".", "line": 58, "column": 12 },
{
"type": "Identifier",
"value": "add",
"content": "add",
"line": 58,
"column": 15
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 58,
"column": 16
},
{
"type": "Identifier",
"value": "neighbors",
"content": "neighbors",
"line": 58,
"column": 25
},
{
"type": "LeftBracket",
"value": "[",
"content": "[",
"line": 58,
"column": 26
},
{
"type": "Identifier",
"value": "i",
"content": "i",
"line": 58,
"column": 27
},
{
"type": "RightBracket",
"value": "]",
"content": "]",
"line": 58,
"column": 28
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 58,
"column": 29
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 59,
"column": 5
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 60,
"column": 3
},
{
"type": "Keyword",
"value": "finished",
"content": "finished",
"line": 62,
"column": 10
},
{
"type": "Identifier",
"value": "alive",
"content": "alive",
"line": 62,
"column": 16
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 63,
"column": 1
},
{
"type": "Keyword",
"value": "sketch",
"content": "sketch",
"line": 65,
"column": 6
},
{
"type": "Identifier",
"value": "painting",
"content": "painting",
"line": 65,
"column": 15
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 65,
"column": 17
},
{
"type": "Keyword",
"value": "loop",
"content": "loop",
"line": 66,
"column": 6
},
{
"type": "Identifier",
"value": "i",
"content": "i",
"line": 66,
"column": 8
},
{
"type": "Keyword",
"value": "through",
"content": "through",
"line": 66,
"column": 16
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 66,
"column": 18
},
{ "type": "Number", "value": "0", "content": 0, "line": 66, "column": 19 },
{ "type": "Comma", "value": ",", "content": ",", "line": 66, "column": 20 },
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 66,
"column": 26
},
{ "type": "Period", "value": ".", "content": ".", "line": 66, "column": 27 },
{
"type": "Identifier",
"value": "length",
"content": "length",
"line": 66,
"column": 33
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 66,
"column": 34
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 66,
"column": 36
},
{
"type": "Keyword",
"value": "prepare",
"content": "prepare",
"line": 67,
"column": 11
},
{
"type": "Identifier",
"value": "cell",
"content": "cell",
"line": 67,
"column": 16
},
{
"type": "Keyword",
"value": "as",
"content": "as",
"line": 67,
"column": 19
},
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 67,
"column": 25
},
{
"type": "LeftBracket",
"value": "[",
"content": "[",
"line": 67,
"column": 26
},
{
"type": "Identifier",
"value": "i",
"content": "i",
"line": 67,
"column": 27
},
{
"type": "RightBracket",
"value": "]",
"content": "]",
"line": 67,
"column": 28
},
{
"type": "Keyword",
"value": "prepare",
"content": "prepare",
"line": 68,
"column": 11
},
{
"type": "Identifier",
"value": "neighbors",
"content": "neighbors",
"line": 68,
"column": 21
},
{
"type": "Keyword",
"value": "as",
"content": "as",
"line": 68,
"column": 24
},
{
"type": "Identifier",
"value": "getNeighbors",
"content": "getNeighbors",
"line": 68,
"column": 37
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 68,
"column": 38
},
{
"type": "Identifier",
"value": "cells",
"content": "cells",
"line": 68,
"column": 43
},
{ "type": "Comma", "value": ",", "content": ",", "line": 68, "column": 44 },
{
"type": "Identifier",
"value": "i",
"content": "i",
"line": 68,
"column": 46
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 68,
"column": 47
},
{
"type": "Keyword",
"value": "if",
"content": "if",
"line": 69,
"column": 6
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 69,
"column": 8
},
{
"type": "Identifier",
"value": "cell",
"content": "cell",
"line": 69,
"column": 12
},
{ "type": "Period", "value": ".", "content": ".", "line": 69, "column": 13 },
{
"type": "Identifier",
"value": "live",
"content": "live",
"line": 69,
"column": 17
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 69,
"column": 18
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 69,
"column": 20
},
{
"type": "Keyword",
"value": "if",
"content": "if",
"line": 70,
"column": 8
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 70,
"column": 10
},
{
"type": "Identifier",
"value": "neighbors",
"content": "neighbors",
"line": 70,
"column": 19
},
{ "type": "Period", "value": ".", "content": ".", "line": 70, "column": 20 },
{
"type": "Identifier",
"value": "length",
"content": "length",
"line": 70,
"column": 26
},
{ "type": "Lt", "value": "<", "content": "<", "line": 70, "column": 28 },
{ "type": "Number", "value": "2", "content": 2, "line": 70, "column": 30 },
{ "type": "Or", "value": "||", "content": "||", "line": 70, "column": 33 },
{
"type": "Identifier",
"value": "neighbors",
"content": "neighbors",
"line": 70,
"column": 43
},
{ "type": "Period", "value": ".", "content": ".", "line": 70, "column": 44 },
{
"type": "Identifier",
"value": "length",
"content": "length",
"line": 70,
"column": 50
},
{ "type": "Gt", "value": ">", "content": ">", "line": 70, "column": 52 },
{ "type": "Number", "value": "3", "content": 3, "line": 70, "column": 54 },
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 70,
"column": 55
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 70,
"column": 57
},
{
"type": "Keyword",
"value": "prepare",
"content": "prepare",
"line": 73,
"column": 15
},
{
"type": "Identifier",
"value": "cell",
"content": "cell",
"line": 73,
"column": 20
},
{ "type": "Period", "value": ".", "content": ".", "line": 73, "column": 21 },
{
"type": "Identifier",
"value": "live",
"content": "live",
"line": 73,
"column": 25
},
{
"type": "Keyword",
"value": "as",
"content": "as",
"line": 73,
"column": 28
},
{ "type": "Boolean", "value": "false", "content": false },
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 74,
"column": 7
},
{
"type": "Keyword",
"value": "elif",
"content": "elif",
"line": 74,
"column": 12
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 74,
"column": 14
},
{ "type": "Not", "value": "!", "content": "!", "line": 74, "column": 15 },
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 74,
"column": 16
},
{
"type": "Identifier",
"value": "cell",
"content": "cell",
"line": 74,
"column": 20
},
{ "type": "Period", "value": ".", "content": ".", "line": 74, "column": 21 },
{
"type": "Identifier",
"value": "live",
"content": "live",
"line": 74,
"column": 25
},
{ "value": "&&", "content": "&&", "line": 74, "column": 28 },
{
"type": "Identifier",
"value": "neighbors",
"content": "neighbors",
"line": 74,
"column": 38
},
{ "type": "Equiv", "value": "==", "content": "==", "line": 74, "column": 41 },
{ "type": "Number", "value": "3", "content": 3, "line": 74, "column": 43 },
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 74,
"column": 44
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 74,
"column": 45
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 74,
"column": 47
},
{
"type": "Keyword",
"value": "prepare",
"content": "prepare",
"line": 76,
"column": 15
},
{
"type": "Identifier",
"value": "cell",
"content": "cell",
"line": 76,
"column": 20
},
{ "type": "Period", "value": ".", "content": ".", "line": 76, "column": 21 },
{
"type": "Identifier",
"value": "live",
"content": "live",
"line": 76,
"column": 25
},
{
"type": "Keyword",
"value": "as",
"content": "as",
"line": 76,
"column": 28
},
{ "type": "Boolean", "value": "true", "content": true },
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 77,
"column": 7
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 78,
"column": 5
},
{
"type": "Keyword",
"value": "if",
"content": "if",
"line": 80,
"column": 6
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 80,
"column": 8
},
{
"type": "Identifier",
"value": "cell",
"content": "cell",
"line": 80,
"column": 12
},
{ "type": "Period", "value": ".", "content": ".", "line": 80, "column": 13 },
{
"type": "Identifier",
"value": "live",
"content": "live",
"line": 80,
"column": 17
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 80,
"column": 18
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 80,
"column": 20
},
{
"type": "Keyword",
"value": "prepare",
"content": "prepare",
"line": 82,
"column": 13
},
{
"type": "Identifier",
"value": "color",
"content": "color",
"line": 82,
"column": 19
},
{
"type": "Keyword",
"value": "as",
"content": "as",
"line": 82,
"column": 22
},
{
"type": "Keyword",
"value": "prep",
"content": "prep",
"line": 82,
"column": 27
},
{
"type": "Identifier",
"value": "Color",
"content": "Color",
"line": 82,
"column": 33
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 82,
"column": 34
},
{
"type": "Identifier",
"value": "r",
"content": "r",
"line": 82,
"column": 35
},
{ "type": "Colon", "value": ":", "content": ":", "line": 82, "column": 36 },
{ "type": "Number", "value": "0", "content": 0, "line": 82, "column": 38 },
{ "type": "Comma", "value": ",", "content": ",", "line": 82, "column": 39 },
{
"type": "Identifier",
"value": "g",
"content": "g",
"line": 82,
"column": 41
},
{ "type": "Colon", "value": ":", "content": ":", "line": 82, "column": 42 },
{
"type": "Number",
"value": "255",
"content": 255,
"line": 82,
"column": 46
},
{ "type": "Comma", "value": ",", "content": ",", "line": 82, "column": 47 },
{
"type": "Identifier",
"value": "b",
"content": "b",
"line": 82,
"column": 49
},
{ "type": "Colon", "value": ":", "content": ":", "line": 82, "column": 50 },
{ "type": "Number", "value": "0", "content": 0, "line": 82, "column": 52 },
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 82,
"column": 53
},
{
"type": "Identifier",
"value": "Canvas",
"content": "Canvas",
"line": 83,
"column": 12
},
{ "type": "Period", "value": ".", "content": ".", "line": 83, "column": 13 },
{
"type": "Identifier",
"value": "fill",
"content": "fill",
"line": 83,
"column": 17
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 83,
"column": 18
},
{
"type": "Identifier",
"value": "cell",
"content": "cell",
"line": 83,
"column": 22
},
{ "type": "Period", "value": ".", "content": ".", "line": 83, "column": 23 },
{
"type": "Identifier",
"value": "x",
"content": "x",
"line": 83,
"column": 24
},
{ "type": "Comma", "value": ",", "content": ",", "line": 83, "column": 25 },
{
"type": "Identifier",
"value": "cell",
"content": "cell",
"line": 83,
"column": 30
},
{ "type": "Period", "value": ".", "content": ".", "line": 83, "column": 31 },
{
"type": "Identifier",
"value": "y",
"content": "y",
"line": 83,
"column": 32
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 83,
"column": 33
},
{
"type": "Identifier",
"value": "ink",
"content": "ink",
"line": 84,
"column": 9
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 84,
"column": 10
},
{
"type": "Identifier",
"value": "Canvas",
"content": "Canvas",
"line": 84,
"column": 16
},
{ "type": "Period", "value": ".", "content": ".", "line": 84, "column": 17 },
{
"type": "Identifier",
"value": "get",
"content": "get",
"line": 84,
"column": 20
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 84,
"column": 21
},
{
"type": "Identifier",
"value": "cell",
"content": "cell",
"line": 84,
"column": 25
},
{ "type": "Period", "value": ".", "content": ".", "line": 84, "column": 26 },
{
"type": "Identifier",
"value": "x",
"content": "x",
"line": 84,
"column": 27
},
{ "type": "Comma", "value": ",", "content": ",", "line": 84, "column": 28 },
{
"type": "Identifier",
"value": "cell",
"content": "cell",
"line": 84,
"column": 33
},
{ "type": "Period", "value": ".", "content": ".", "line": 84, "column": 34 },
{
"type": "Identifier",
"value": "y",
"content": "y",
"line": 84,
"column": 35
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 84,
"column": 36
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 84,
"column": 37
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 85,
"column": 5
},
{
"type": "Keyword",
"value": "else",
"content": "else",
"line": 85,
"column": 10
},
{
"type": "LeftBrace",
"value": "{",
"content": "{",
"line": 85,
"column": 12
},
{
"type": "Identifier",
"value": "Canvas",
"content": "Canvas",
"line": 87,
"column": 12
},
{ "type": "Period", "value": ".", "content": ".", "line": 87, "column": 13 },
{
"type": "Identifier",
"value": "erase",
"content": "erase",
"line": 87,
"column": 18
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 87,
"column": 19
},
{
"type": "Identifier",
"value": "cell",
"content": "cell",
"line": 87,
"column": 23
},
{ "type": "Period", "value": ".", "content": ".", "line": 87, "column": 24 },
{
"type": "Identifier",
"value": "x",
"content": "x",
"line": 87,
"column": 25
},
{ "type": "Comma", "value": ",", "content": ",", "line": 87, "column": 26 },
{
"type": "Identifier",
"value": "cell",
"content": "cell",
"line": 87,
"column": 31
},
{ "type": "Period", "value": ".", "content": ".", "line": 87, "column": 32 },
{
"type": "Identifier",
"value": "y",
"content": "y",
"line": 87,
"column": 33
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 87,
"column": 34
},
{
"type": "Identifier",
"value": "ink",
"content": "ink",
"line": 88,
"column": 9
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 88,
"column": 10
},
{
"type": "Identifier",
"value": "Canvas",
"content": "Canvas",
"line": 88,
"column": 16
},
{ "type": "Period", "value": ".", "content": ".", "line": 88, "column": 17 },
{
"type": "Identifier",
"value": "get",
"content": "get",
"line": 88,
"column": 20
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 88,
"column": 21
},
{
"type": "Identifier",
"value": "cell",
"content": "cell",
"line": 88,
"column": 25
},
{ "type": "Period", "value": ".", "content": ".", "line": 88, "column": 26 },
{
"type": "Identifier",
"value": "x",
"content": "x",
"line": 88,
"column": 27
},
{ "type": "Comma", "value": ",", "content": ",", "line": 88, "column": 28 },
{
"type": "Identifier",
"value": "cell",
"content": "cell",
"line": 88,
"column": 33
},
{ "type": "Period", "value": ".", "content": ".", "line": 88, "column": 34 },
{
"type": "Identifier",
"value": "y",
"content": "y",
"line": 88,
"column": 35
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 88,
"column": 36
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 88,
"column": 37
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 89,
"column": 5
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 90,
"column": 3
},
{
"type": "RightBrace",
"value": "}",
"content": "}",
"line": 91,
"column": 1
},
{
"type": "Identifier",
"value": "painting",
"content": "painting",
"line": 93,
"column": 8
},
{
"type": "LeftParen",
"value": "(",
"content": "(",
"line": 93,
"column": 9
},
{
"type": "RightParen",
"value": ")",
"content": ")",
"line": 93,
"column": 10
},
{
"type": "EOF",
"value": "\u0000",
"content": "\u0000",
"line": 93,
"column": 10
}
]
Isn't that cool? We've done that in a little more than 200 lines of code. That's pretty cool. The next step is to start combining tokens into a grammar that represents our programming language, which is what writing a parser will do for us.
The complete code here is at lexer.js.