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package token // import "monkey/token"

//go:generate stringer -type=TokenType

type TokenType int

const (
	ILLEGAL TokenType = iota
	EOF

	// Identifiers + literals
	IDENT   // add, foobar, x, y, ...
	INTEGER // 1343456
	STRING  // "foobar"

	// Operators
	ASSIGN   // "="
	PLUS     // "+"
	MINUS    // "-"
	BANG     // "!"
	ASTERISK // "*"
	SLASH    // "/"
	LESS     // "<"
	MORE     // ">"
	EQ       // "=="
	NOT_EQ   // "!="

	// Delimiters
	COMMA     // ","
	SEMICOLON // ";"
	COLON     // ":"
	LPAREN    // "("
	RPAREN    // ")"
	LBRACE    // "{"
	RBRACE    // "}"
	LBRACKET  // "["
	RBRACKET  // "]"

	// Keywords
	FUNCTION
	LET
	TRUE
	FALSE
	IF
	ELSE
	RETURN
	MACRO
)

type Token struct {
	Type    TokenType
	Literal string
}

var keywords = map[string]TokenType{
	"fn":     FUNCTION,
	"let":    LET,
	"true":   TRUE,
	"false":  FALSE,
	"if":     IF,
	"else":   ELSE,
	"return": RETURN,
	"macro":  MACRO,
}

func LookupIdent(ident string) TokenType {
	if tok, ok := keywords[ident]; ok {
		return tok
	}
	return IDENT
}