go-parsekit/tokenize/api_test.go

package tokenize_test

import (
	"fmt"

	"git.makaay.nl/mauricem/go-parsekit/tokenize"
)

func ExampleNewAPI() {
	tokenize.NewAPI("The input that the API will handle")

	// Output:
}

func ExampleAPI_NextRune() {
	api := tokenize.NewAPI("The input that the API will handle")
	r, err := api.NextRune()

	fmt.Printf("Rune read from input; %c\n", r)
	fmt.Printf("The error: %v\n", err)
	fmt.Printf("API results: %q\n", api.Result().String())

	// Output:
	// Rune read from input; T
	// The error: <nil>
	// API results: ""
}

func ExampleAPI_Accept() {
	api := tokenize.NewAPI("The input that the API will handle")
	api.NextRune() // reads 'T'
	api.Accept()   // adds 'T' to the API results
	api.NextRune() // reads 'h'
	api.Accept()   // adds 'h' to the API results
	api.NextRune() // reads 'e', but it is not added to the API results

	fmt.Printf("API results: %q\n", api.Result().String())

	// Output:
	// API results: "Th"
}

func ExampleAPI_Result() {
	api := tokenize.NewAPI("")

	result := api.Result()

	result.AddRunes("Some runes")
	result.AddRunes([]rune{' ', 'a', 'd', 'd', 'e', 'd'})
	result.AddRunes(' ', 'i', 'n', ' ', "various ways")
	fmt.Printf("API result first 10 runes: %q\n", api.Result().Runes()[0:10])
	fmt.Printf("API result runes as string: %q\n", api.Result().String())

	result.SetRunes("new ", "set ", "of ", 'r', 'u', 'n', 'e', 's')
	fmt.Printf("API result runes as string: %q\n", api.Result().String())
	fmt.Printf("API result runes: %q\n", api.Result().Runes())
	fmt.Printf("API third rune: %q\n", api.Result().Rune(2))

	result.AddTokens(&tokenize.Token{
		Runes: []rune("demo 1"),
		Type:  42,
		Value: "towel"})
	result.AddTokens(&tokenize.Token{
		Runes: []rune("demo 2"),
		Type:  73,
		Value: "Zaphod"})
	fmt.Printf("API result tokens: %v\n", api.Result().Tokens())
	fmt.Printf("API second result token: %v\n", api.Result().Token(1))

	// Output:
	// API result first 10 runes: ['S' 'o' 'm' 'e' ' ' 'r' 'u' 'n' 'e' 's']
	// API result runes as string: "Some runes added in various ways"
	// API result runes as string: "new set of runes"
	// API result runes: ['n' 'e' 'w' ' ' 's' 'e' 't' ' ' 'o' 'f' ' ' 'r' 'u' 'n' 'e' 's']
	// API third rune: 'w'
	// API result tokens: [42("demo 1", value = (string)towel) 73("demo 2", value = (string)Zaphod)]
	// API second result token: 73("demo 2", value = (string)Zaphod)
}

func ExampleAPI_Reset() {
	api := tokenize.NewAPI("Very important input!")

	api.NextRune()
	api.Accept()
	api.NextRune()
	api.Accept()
	fmt.Printf("API results: %q at %s\n", api.Result().String(), api.Result().Cursor())

	// Reset clears the results, but keeps the cursor position.
	api.Reset()
	fmt.Printf("API results: %q at %s\n", api.Result().String(), api.Result().Cursor())

	api.NextRune()
	api.Accept()
	api.NextRune()
	api.Accept()
	fmt.Printf("API results: %q at %s\n", api.Result().String(), api.Result().Cursor())

	// Output:
	// API results: "Ve" at line 1, column 3
	// API results: "" at line 1, column 3
	// API results: "ry" at line 1, column 5
}

func ExampleAPI_Fork() {
	// This custom Handler checks for input 'a', 'b' or 'c'.
	abcHandler := func(t *tokenize.API) bool {
		a := tokenize.A
		for _, r := range []rune{'a', 'b', 'c'} {
			child := t.Fork() // fork, so we won't change parent t
			if a.Rune(r)(child) {
				child.Merge() // accept results into parent t
				return true   // and report a successful match
			}
		}
		// If we get here, then no match was found. Return false to communicate
		// this to the caller.
		return false
	}

	// Note: a custom Handler is normally not what you need.
	// You can make use of the parser/combinator tooling to make the
	// implementation a lot simpler and to take care of forking at
	// the appropriate places. The handler from above can be replaced with:
	simpler := tokenize.A.RuneRange('a', 'c')

	result, err := tokenize.New(abcHandler)("another test")
	fmt.Println(result, err)
	result, err = tokenize.New(simpler)("curious")
	fmt.Println(result, err)
	result, err = tokenize.New(abcHandler)("bang on!")
	fmt.Println(result, err)
	result, err = tokenize.New(abcHandler)("not a match")
	fmt.Println(result, err)

	// Output:
	// a <nil>
	// c <nil>
	// b <nil>
	// <nil> mismatch at start of file
}

func ExampleAPI_Dispose() {
	api := tokenize.NewAPI("My uninspired piece of input")

	child := api.Fork()
	// ... do stuff with child ...
	child.NextRune()
	child.Accept()
	child.NextRune()
	child.Accept()
	// ... dispose of the child results ...
	child.Dispose()

	// The parent still reads from the start of the input.
	r, _ := api.NextRune()
	fmt.Printf("Rune read from parent: %c\n", r)

	// Output:
	// Rune read from parent: M
}

func ExampleAPI_Merge() {
	tokenHandler := func(t *tokenize.API) bool {
		child1 := t.Fork()
		child1.NextRune() // reads 'H'
		child1.Accept()
		child1.NextRune() // reads 'i'
		child1.Accept()

		child2 := child1.Fork()
		child2.NextRune() // reads ' '
		child2.Accept()
		child2.NextRune() // reads 'd'
		child2.Accept()

		child1.Merge() // We merge child1, which has read 'H' and 'i' only.
		return true
	}

	result, _ := tokenize.New(tokenHandler)("Hi mister X!")
	fmt.Println(result)

	// Output:
	// Hi
}