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|
package markdown
import (
"fmt"
"html/template"
)
type astLink struct {
content block
href block
}
func (a *astLink) Eval() (template.HTML, *ParseError) {
content, err := a.content.Eval()
if err != nil {
return "", err
}
href, err := a.href.Eval()
if err != nil {
return "", err
}
return template.HTML(fmt.Sprintf(`<a href="%s">%s</a>`, href, content)), nil
}
type astImage struct {
alt block
src block
source []*astParagraph
}
func (a *astImage) Eval() (template.HTML, *ParseError) {
alt, err := a.alt.Eval()
if err != nil {
return "", err
}
src, err := a.src.Eval()
if err != nil {
return "", err
}
if a.source == nil {
return template.HTML(fmt.Sprintf(`<figure><img alt="%s" src="%s"></figure>`, alt, src)), nil
}
var s template.HTML
for _, c := range a.source {
ct, err := c.Eval()
if err != nil {
return "", err
}
s += ct + " "
}
s = s[:len(s)-1]
return template.HTML(fmt.Sprintf(`<figure><img alt="%s" src="%s"><figcaption>%s</figcaption></figure>`, alt, src, s)), nil
}
func external(lxs *lexers) (block, *ParseError) {
tp := lxs.Current().Value
if !lxs.Next() {
return astLiteral(tp), nil
}
lxs.Before() // because we call Next
var b block
var err *ParseError
switch tp {
case "![":
b, err = image(lxs)
case "[":
b, err = link(lxs)
default:
b = astLiteral(tp)
}
return b, err
}
func link(lxs *lexers) (block, *ParseError) {
lk := new(astLink)
start := lxs.current
content, href, _, ok := parseExternal(lxs, false)
if !ok {
return reset(lxs, start), nil
}
lk.content = astLiteral(content)
lk.href = astLiteral(href)
return lk, nil
}
func image(lxs *lexers) (block, *ParseError) {
img := new(astImage)
start := lxs.current
alt, src, source, ok := parseExternal(lxs, true)
if !ok {
return reset(lxs, start), nil
}
img.alt = astLiteral(alt)
img.src = astLiteral(src)
img.source = source
return img, nil
}
func parseExternal(lxs *lexers, withSource bool) (string, string, []*astParagraph, bool) {
next := false
var s string
var first string
var end string
var ps []*astParagraph
n := 0
fn := func() bool {
p, err := paragraph(lxs, true)
if err != nil {
return false
}
ps = append(ps, p)
n = 0
return true
}
for lxs.Next() && n < 2 {
switch lxs.Current().Type {
case lexerBreak:
if !withSource {
return "", "", nil, false
}
n += len(lxs.Current().Value)
if first != "" && end != "" {
if !lxs.Next() {
return first, end, ps, true
}
ok := fn()
if !ok {
return "", "", nil, false
}
lxs.Before() // because we must parse lexerBreak
}
case lexerExternal:
if first != "" && end != "" {
return "", "", nil, false
}
if n > 0 && (first == "" || end == "") {
return "", "", nil, false
}
n = 0
if !next {
if lxs.Current().Value != "](" || !lxs.Next() {
return "", "", nil, false
}
lxs.Before() // because we called Next
first = s
s = ""
next = true
} else {
if lxs.Current().Value != ")" {
return "", "", nil, false
}
if !withSource {
return first, s, nil, true
}
end = s
s = ""
if lxs.Next() && lxs.Current().Type != lexerBreak {
return "", "", nil, false
}
lxs.Before() // because we called Next
}
default:
if ps != nil {
return "", "", nil, false
}
n = 0
s += lxs.Current().Value
}
}
if !withSource {
return "", "", nil, false
}
return first, end, ps, true
}
func reset(lxs *lexers, start int) block {
lxs.current = start
return astLiteral(lxs.Current().Value)
}
|
