unilex/scanners.go

47 lines
1.1 KiB
Go
Raw Normal View History

2021-03-06 22:30:32 +03:00
package unilex
// ScanNumber simplest scanner that accepts decimal int and float.
func ScanNumber(l *Lexer) bool {
l.AcceptWhile("0123456789")
if l.AtStart() {
// not found any digit
return false
}
l.Accept(".")
l.AcceptWhile("0123456789")
return !l.AtStart()
}
// ScanAlphaNum returns true if next input token contains alphanum sequence that not starts from digit and not contains.
// spaces or special characters.
func ScanAlphaNum(l *Lexer) bool {
digits := "0123456789"
alpha := "qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM"
if !l.Accept(alpha) {
return false
}
l.AcceptWhile(alpha + digits)
return true
}
2021-03-07 01:32:29 +03:00
// ScanQuotedString returns true if next input tokens is quoted string. Can be used with any type of quotes.
func ScanQuotedString(l *Lexer, quote rune) bool {
start := l.Pos
if l.Next() != quote {
l.Back()
return false
}
for {
ch := l.Next()
switch ch {
case EOF:
l.Pos = start // Return position to start
return false // Unclosed quote string?
case '\\':
l.Next() // Skip next char
case quote:
return true // Closing quote
}
}
}