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package mardown
import "fmt"
type lexerType string
const (
lexerBreak lexerType = "break"
lexerEscape lexerType = "escape"
lexerModifier lexerType = "modifier"
lexerCode lexerType = "code"
lexerHeader lexerType = "header"
lexerQuote lexerType = "quote"
lexerExternal lexerType = "external"
lexerLiteral lexerType = "literal"
)
type lexer struct {
Type lexerType
Value string
}
func (l *lexer) String() string {
return fmt.Sprintf("%s(%s)", l.Type, l.Value)
}
type lexers struct {
current int
lexers []lexer
}
func (l *lexers) Next() bool {
l.current++
return !l.Finished()
}
func (l *lexers) Current() lexer {
return l.lexers[l.current]
}
func (l *lexers) Finished() bool {
return l.current >= len(l.lexers)
}
func (l *lexers) String() string {
s := "Lexers["
for _, l := range l.lexers {
s += l.String() + " "
}
return s + "]"
}
func lex(s string) *lexers {
lxs := &lexers{current: -1}
var lexs []lexer
var currentType lexerType
var previous string
fn := func(c rune, t lexerType) {
if currentType != t && len(previous) > 0 {
lexs = append(lexs, lexer{Type: currentType, Value: previous})
previous = ""
}
currentType = t
previous += string(c)
}
for _, c := range []rune(s) {
switch c {
case '*', '_':
fn(c, lexerModifier)
case '`':
fn(c, lexerCode)
case '\n':
fn(c, lexerBreak)
case '#':
fn(c, lexerHeader)
case '>':
fn(c, lexerQuote)
case '[', ']', '(', ')', '!':
fn(c, lexerExternal)
case '\\':
fn(c, lexerEscape)
default:
fn(c, lexerLiteral)
}
}
if len(previous) > 0 {
lexs = append(lexs, lexer{Type: currentType, Value: previous})
}
lxs.lexers = lexs
return lxs
}
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