You want different tokenizer types to be used in the same WalkBody
implementation. Interfaces abstract the implementation from the calling
computation.
I think Ian did answer your question.
type TokenVisitor interface {
VisitToken()
}
func WalkBody(of TokenVisitor) {
// here you call of.VisitToken()
}
type MyTokenizer1 struct {
*html.Tokenizer
}
func (the MyTokenizer1) VisitToken() {
}
type MyTokenizer2 struct {
*html.Tokenizer
}
func (the MyTokenizer2) VisitToken() {
}
// call WalkBody somewhere with either MyTokenizer1 or MyTokenizer2
When I wanted to write one list of tests for two different set types I
added set.go and set_test.go here: https://github.com/pciet/pathsetbenchmark
Matt
On Tuesday, January 2, 2018 at 8:45:56 AM UTC-6, Tong Sun wrote:
>
>
>
> On Mon, Jan 1, 2018 at 9:46 PM, Tong Sun <sunto...@gmail.com <javascript:>
> > wrote:
>
>> Hi,
>>
>> I think I generally understand how embedding (
>> https://golang.org/doc/effective_go.html#embedding) works in GO.
>> However, when it comes to the following problem, I'm at lost again.
>>
>> I'm trying to extend the `html.Tokenizer` with new methods of my own:
>>
>> type MyTokenizer struct {
>> html.Tokenizer
>> }
>>
>>
>> func NewMyTokenizer(i io.Reader) *MyTokenizer {
>> z := html.NewTokenizer(i)
>> return *MyTokenizer(z)
>> return &MyTokenizer{z}
>> }
>>
>>
>>
>> so code like
>>
>> z := html.NewTokenizer(body)
>> ...
>> func parseBody(z *html.Tokenizer) {
>> tt := z.Next()
>> ...
>> testt := z.Token()
>> ...
>>
>>
>> can become:
>>
>> z := NewMyTokenizer(body)
>> ...
>> func (z *MyTokenizer) parseBody() {
>> tt := z.Next()
>> ...
>>
>> testt := z.Token()
>> ...
>>
>>
>>
>>
>> However, I'm really struggling to make it work as I was expected.
>>
>> Somebody help please, what's the proper way to extend a type with new
>> methods of my own, while still able to access all existing methods?
>>
>
>
> Thanks to Jason Phillips' help, the above part is solved:
>
> type MyTokenizer struct {
> *html.Tokenizer
> }
>
> func NewMyTokenizer(i io.Reader) *MyTokenizer {
> z := html.NewTokenizer(i)
> return &MyTokenizer{z}
> }
>
> What's remaining is,
>
> Further more, how to extend the above even further? --
>>
>> - I plan to define an interface with a new method `WalkBody()`, in which
>> a "virtual" method of `VisitToken()` is used.
>> - Then I plan to define two different type of MyTokenizer, with their
>> own `VisitToken()` methods, so the same `WalkBody()` method defined in
>> MyTokenizer will behave differently for those two different types.
>>
>> How to architect above in Go?
>>
>
> I've found this afterward,
>
> http://hackthology.com/object-oriented-inheritance-in-go.html
>
> I'll digest and try it out, and see how that can solve the above problem,
> because it builds bottom up (not mid-way up).
>
> Meanwhile, if someone can explain how to think and solve such problem in
> Go, that'd be much appreciated. Only at the architectural level would be
> fine for me, I can try it out myself. The real problem to me is that I have
> a *systematic *thinking in OO how to solve such kind of inherit & enhance
> problem, and there is a *practical *implementation in place for me, the
> virtual functions. But when it comes to Go, I still need help for how to
> *think*, and how to *do*.
>
> Thanks!
>
>
>>
>> For your convenience, you can use this as an easy start, when
>> demonstrating your architectural solution.
>>
>> https://github.com/suntong/lang/blob/master/lang/Go/src/xml/htmlParserTokens.go
>>
>>
>> Thx a lot!
>>
>>
>> --
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>
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