token/token.go


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54

package token

const (
	ILLEGAL = "ILLEGAL"
	EOF     = "EOF"

	// Identifiers and literals
	IDENT = "IDENT"
	INT   = "INT"

	// Operators
	ASSIGN   = "="
	PLUS     = "+"
	MINUS    = "-"
	BANG     = "!"
	ASTERISK = "*"
	SLASH    = "/"

	LT = "<"
	GT = ">"

	// Delimiters
	COMMA     = ","
	SEMICOLON = ";"

	LPAREN = "("
	RPAREN = ")"
	LBRACE = "{"
	RBRACE = "}"

	// Keywords
	FUNCTION = "FUNCTION"
	LET      = "LET"
)

var keywords = map[string]TokenType{
	"fn":  FUNCTION,
	"let": LET,
}

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

	return IDENT
}

type TokenType string

type Token struct {
	Type    TokenType
	Literal string
}