func Example_Function() {
re := regexp.MustCompile(`(\d+)\+(\d+)=(?{add})`)
re.Funcs(syntax.FuncMap{
"add": func(ctx syntax.Context) interface{} {
lhs, err := strconv.Atoi(string(ctx.Data[ctx.Matches[1][0]:ctx.Matches[1][1]]))
if err != nil {
return -1
}
rhs, err := strconv.Atoi(string(ctx.Data[ctx.Matches[2][0]:ctx.Matches[2][1]]))
if err != nil {
return -1
}
answer := strconv.Itoa(lhs + rhs)
if bytes.HasPrefix(ctx.Data[ctx.Cursor:], []byte(answer)) {
return len(answer)
}
return -1
},
})
fmt.Println(re.MatchString("12+10=22"))
fmt.Println(re.MatchString("1+1=5"))
// Output:
// true
// false
}
func Example_Lookahead() {
re := regexp.MustCompile(`a(?=[0-9]{3})1`)
fmt.Println(re.MatchString("a123"))
fmt.Println(re.MatchString("a12a"))
// Output:
// true
// false
}
func Example_Lookbehind() {
re := regexp.MustCompile(`(?<=a[0-9]{3,5})a`)
fmt.Println(re.MatchString("a12a"))
fmt.Println(re.MatchString("a12345a"))
// Output:
// false
// true
}
func Example_AtomicGroup() {
re := regexp.MustCompile(`^(?>[0-9]+)[0-9a]`)
fmt.Println(re.MatchString("1234a"))
fmt.Println(re.MatchString("1234"))
// Output:
// true
// false
}
func Example_PossessiveQualifiers() {
re := regexp.MustCompile(`^[0-9]++[0-9a]`)
fmt.Println(re.MatchString("1234a"))
fmt.Println(re.MatchString("1234"))
// Output:
// true
// false
}
func Example_BackReference() {
re := regexp.MustCompile(`^(\w)\w+\k{1}$`)
fmt.Println(re.MatchString("acca"))
fmt.Println(re.MatchString("accccab"))
fmt.Println(re.MatchString("AA"))
// Output:
// true
// false
// false
}
func Example() {
// Compile the expression once, usually at init time.
// Use raw strings to avoid having to quote the backslashes.
var validID = regexp.MustCompile(`^(\w)\w+\k{1}\[[0-9]+\]$`)
fmt.Println(validID.MatchString("adam[23]"))
fmt.Println(validID.MatchString("eve[7]"))
fmt.Println(validID.MatchString("Job[48]"))
fmt.Println(validID.MatchString("snakey"))
// Output:
// false
// true
// false
// false
}
func Example_Comment() {
re := regexp.MustCompile(`(?#comment here)1234`)
fmt.Println(re.MatchString("1234"))
// Output:
// true
}