A tour of Go: Exercise: Readers

go_reader_ex.go

package main

import "code.google.com/p/go-tour/reader"


type MyReader struct{}

func (r MyReader) Read(bytes []byte) (int, error) {
	for i := range bytes {
		bytes[i] = 65
	}
	return len(bytes), nil
}
// TODO: Add a Read([]byte) (int, error) method to MyReader.

func main() {
	reader.Validate(MyReader{})
}

package main

import "golang.org/x/tour/reader"

// TODO: Add a Read([]byte) (int, error) method to MyReader.

type MyReader struct{}
type MyReaderError bool

func (MyReaderError) Error() string {
	return "too short b capacity"
}

func (MyReader) Read(b []byte) (int, error) {
	if cap(b) < 1 {
		return 0, MyReaderError(true)
	}
	b[0] = 'A'
	return 1, nil
}

func main() {
	reader.Validate(MyReader{})
}

package main

import "golang.org/x/tour/reader"

type MyReader struct{}
type MyReaderError int

func (e MyReaderError) Error() string {
	return "capacity max error, cap: " + string(e)
}

// TODO: Add a Read([]byte) (int, error) method to MyReader.
func (myReader MyReader) Read(b []byte) (int, error) {
	if cap(b) < 1 {
		return 0, MyReaderError(cap(b))
	}
	
	b[0] = 'A'
	return 1, nil
}

func main() {
	reader.Validate(MyReader{})
}

The description of the problem didn't make sense to me. Thank you for the solution.

The description of the problem didn't make sense to me. Thank you for the solution.

You are welcome