Files
wyst/lexer.go
T
2024-08-09 21:05:03 +02:00

55 lines
1.1 KiB
Go

package main
import (
"fmt"
"strings"
"github.com/wyst-lang/wyst/token"
)
type State struct {
Line int
Column int
}
type Token struct {
Rule token.Rule
Value string
Position State
}
func (t Token) String() string {
return fmt.Sprintf("Token(\n rule=%s,\n value=%s\n)", t.Rule, t.Value)
}
func Tokenize(code string, rules []token.Rule) ([]Token, error) {
var tokens = []Token{}
var state = State{1, 0}
for code != "" {
matched := false
for i := 0; i < len(rules); i++ {
if rules[i].Pattern.MatchString(code) {
match := rules[i].Pattern.FindString(code)
matched = true
code = code[len(match):]
tokens = append(tokens, Token{Rule: rules[i], Value: match, Position: state})
state.Column += len(match)
break
} else if strings.HasPrefix(code, "\n") {
state.Line += 1
state.Column = 0
code = code[1:]
matched = true
} else if strings.HasPrefix(code, "\t") || strings.HasPrefix(code, " ") {
state.Column += 1
code = code[1:]
matched = true
}
}
if !matched {
return tokens, fmt.Errorf("%d:%d", state.Line, state.Column)
}
}
return tokens, nil
}