func ExampleAlt() {
var r interface{}
var ok bool
prt := func() {
if ok {
fmt.Printf("Result: %s\n", utf88.Surr(r.(utf88.Text)))
} else {
fmt.Printf("Error: %v\n", r)
}
}
lower := kern.Regexp(`\p{Ll}`)
upper := kern.Regexp(`\p{Lu}`)
digit := kern.Regexp(`\p{Nd}`)
p := kern.Alt(lower, digit)
q := kern.Alt(lower, digit, upper)
t := utf88.Text("7ef")
u := utf88.Text(";ef")
r, ok = kern.ParseText(p, t)
prt()
r, ok = kern.ParseText(p, u)
prt()
r, ok = kern.ParseText(q, t)
prt()
// Output:
// Result: 7
// Error: No alternatives selected.
// Result: 7
}
func ExampleTry() {
p := kern.Flatten(kern.Regexp(`\pL`), kern.Regexp(`\pL`))
q := kern.Flatten(kern.Regexp(`\pL`), kern.Regexp(`\pN`))
t := utf88.Text("a7bcde")
var r interface{}
var ok bool
prt := func() {
if ok {
fmt.Printf("Result: %s\n", utf88.Surr(r.(utf88.Text)))
} else {
fmt.Printf("Error: %v\n", r)
}
}
r, ok = kern.ParseText(kern.Alt(p, q), t)
prt()
r, ok = kern.ParseText(kern.Alt(kern.Try(p), q), t)
prt()
// Output:
// Error: Unexpected 7 input.
// Result: a7
}
func ExampleFwdWithParams() {
var expr func(...interface{}) kern.Parser
paren := func(as ...interface{}) kern.Parser {
return kern.SeqRight(kern.Token(utf88.Text(string('('))),
kern.SeqLeft(kern.FwdWithParams(expr, as...), // FwdWithParams will evaluate passed expression lazily
kern.Token(utf88.Text(string(')')))))
}
expr = func(as ...interface{}) kern.Parser { // will parse string enclosed in parenthesis pairs to any depth
return kern.Alt(kern.Token(utf88.Text(string('a'))),
paren(as...))
}
t := utf88.Text("(((a)))")
r, ok := kern.ParseText(expr(101, 102), t) // call expr with extra (unused in this e.g.) args
if ok {
fmt.Printf("Result: %s\n", utf88.Surr(r.(utf88.Text)))
} else {
fmt.Printf("Error: %v\n", r)
}
// Output:
// Result: a
}
func ExampleFwd() {
var expr func() kern.Parser
paren := func() kern.Parser {
return kern.SeqRight(kern.Token(utf88.Text(string('('))),
kern.SeqLeft(kern.Fwd(expr), // Fwd will evaluate passed expression lazily
kern.Token(utf88.Text(string(')')))))
}
expr = func() kern.Parser { // will parse string enclosed in parenthesis pairs to any depth
return kern.Alt(kern.Token(utf88.Text(string('a'))),
paren())
}
t := utf88.Text("(((a)))")
r, ok := kern.ParseText(expr(), t)
if ok {
fmt.Printf("Result: %s\n", utf88.Surr(r.(utf88.Text)))
} else {
fmt.Printf("Error: %v\n", r)
}
// Output:
// Result: a
}