nickdances / waiig-commentary

An exploration, commentary, and extension of https://interpreterbook.com/

Quick Start

Install

git clone [e-mail]:nicholasgriffen/waiig-commentary.git

Start repl

cd waiig-commentary
go run main.go

Update docs

godocdown

go get github.com/robertkrimen/godocdown/godocdown
godocdown /path/to/package > package.md
cat package.md >> README.md

repl

-- import "interpreter/repl"

Usage

func Start

func Start(in io.Reader, out io.Writer)

Start reads lines in and writes tokens out

lexer

-- import "interpreter/lexer"

BUG(nicholasgriffen): Lexers lack Unicode, UTF-8 support

Usage

type Lexer

type Lexer struct {
}

Lexer takes source code and returns tokens

func New

func New(input string) Lexer

New takes string and returns initialized lexer

func (*Lexer) NextToken

func (lexer *Lexer) NextToken() token.Token

NextToken creates token and steps position

token

-- import "interpreter/token"

BUG(nicholasgriffen): Tokens lack filenames, linenumbers

Usage

const (
	//ILLEGAL unknown type
	ILLEGAL = "ILLEGAL"
	//IDENT identifier
	IDENT = "IDENT"
	//FUNCTION function declaration
	FUNCTION = "FUNCTION"
	//RETURN end function execution with return value
	RETURN = "RETURN"
	//LET identifier naming
	LET = "LET"
	//TRUE boolean false
	TRUE = "TRUE"
	//FALSE boolean false
	FALSE = "FALSE"
	//IF if control flow
	IF = "IF"
	//ELSE else control flow
	ELSE = "ELSE"
	//IS comparison
	IS = "=="
	//ISNOT comparison
	ISNOT = "!="
	//EOF end of file
	EOF = ""
	//INT integer
	INT = "INT"
	//ASSIGN identifier assignment
	ASSIGN = "="
	//PLUS sum
	PLUS = "+"
	//MINUS subtract
	MINUS = "-"
	//STAR asterisk
	STAR = "*"
	//FSLASH forward slash
	FSLASH = "/"
	//COMMA expression separator{}
	COMMA = ","
	//SEMICOLON statement terminator
	SEMICOLON = ";"
	//BANG exclamation point
	BANG = "!"
	//LTHAN open angle
	LTHAN = "<"
	//RTHAN close angle
	RTHAN = ">"
	//LROUND open grouping
	LROUND = "("
	//RROUND close grouping
	RROUND = ")"
	//LCURLY open block
	LCURLY = "{"
	//RCURLY close block
	RCURLY = "}"
)

type Token

type Token struct {
	Type    TokenType
	Literal string
}

Token keywords, symbols

type TokenType

type TokenType string

TokenType matters downstream

func FindIdent

func FindIdent(ident string) TokenType

FindIdent takes string and looks up TokenType