CODEWITHSUNDEEP
gomarkdown
wyc
wyc

Reputation: 55263

Go: How to use the func() bool arguments in go?

This is a sample code from the Go blackfriday package:

package main

import (
    "bytes"
    "fmt"
    "github.com/russross/blackfriday"
)

func main() {

input := []byte(`##Title

- another paragragh

This is a being rendered in a custom way.
`)

    htmlFlags := 0
    renderer := &renderer{Html: blackfriday.HtmlRenderer(htmlFlags, "", "").(*blackfriday.Html)}

    extensions := 0

    unsanitized := blackfriday.Markdown(input, renderer, extensions)
    os.Stdout.Write(unsanitized)
}

// renderer implements blackfriday.Renderer and reuses blackfriday.Html for the most part,
// except overriding Link rendering.
type renderer struct {
    *blackfriday.Html
}

func (options *renderer) Header(out *bytes.Buffer, text func() bool, level int, id string) {
    fmt.Fprintf(out, "<custom link %q to %q>", content, link)
}

The purpose of the code is to customize the link attributes of the output HTML.

I tried to do the same but with p tags:

func (options *renderer) Paragraph(out *bytes.Buffer, text func() bool) {
    fmt.Fprintf(out, "<p class='custom'>%q</p>", text)
}

But the output was this:

<h1>Title</h1>

<ul>
<li>another paragragh</li>
</ul>
<p class='custom'>%!q(func() bool=0x80a15d0)</p>

So I have no idea how to output the actual text (This is a being rendered in a custom way.). Any ideas?

This is the source code of the function:

func (options *Html) Paragraph(out *bytes.Buffer, text func() bool) {
    marker := out.Len()
    doubleSpace(out)

    out.WriteString("<p>")
    if !text() {
        out.Truncate(marker)
        return
    }
    out.WriteString("</p>\n")
}

Upvotes: 0

Views: 101

Answers (2)

Jaemin Park
Jaemin Park

Reputation: 270

I think your usage of function is wrong.

Take a look at Html.Paragraph and override this.

Maybe it would look like:

func (options *renderer) Paragraph(out *bytes.Buffer, text func() bool) {
    marker := out.Len()
    doubleSpace(out) 

    out.WriteString("<p class='custom'>")
    if !text() {
        out.Truncate(marker)
        return
    }
    out.WriteString("</p>\n")
}

Upvotes: 1

sberry
sberry

Reputation: 131968

I believe all you need to do is call text 

func (options *renderer) Paragraph(out *bytes.Buffer, text func() bool) {
    fmt.Fprintf(out, "<p class='custom'>%q</p>\n", text())
}

Upvotes: 1

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