1
0
mirror of https://github.com/osmarks/mycorrhiza.git synced 2024-12-13 14:00:25 +00:00
mycorrhiza/gemtext/lexer.go
2020-08-29 00:17:32 +05:00

174 lines
4.4 KiB
Go

package gemtext
import (
"fmt"
"html"
"path"
"strings"
)
// HyphaExists holds function that checks that a hypha is present.
var HyphaExists func(string) bool
// HyphaAccess holds function that accesses a hypha by its name.
var HyphaAccess func(string) (rawText, binaryHtml string, err error)
// GemLexerState is used by gemtext parser to remember what is going on.
type GemLexerState struct {
// Name of hypha being parsed
name string
where string // "", "list", "pre"
// Line id
id int
buf string
}
type Line struct {
id int
// interface{} may be bad. What I need is a sum of string and Transclusion
contents interface{}
}
// Parse gemtext line starting with "=>" according to wikilink rules.
// See http://localhost:1737/page/wikilink
func wikilink(src string, state *GemLexerState) (href, text, class string) {
src = strings.TrimSpace(remover("=>")(src))
if src == "" {
return
}
// Href is text after => till first whitespace
href = strings.Fields(src)[0]
// Text is everything after whitespace.
// If there's no text, make it same as href
if text = strings.TrimPrefix(src, href); text == "" {
text = href
}
class = "wikilink_internal"
switch {
case strings.HasPrefix(href, "./"):
hyphaName := canonicalName(path.Join(
state.name, strings.TrimPrefix(href, "./")))
if !HyphaExists(hyphaName) {
class = "wikilink_new"
}
href = path.Join("/page", hyphaName)
case strings.HasPrefix(href, "../"):
hyphaName := canonicalName(path.Join(
path.Dir(state.name), strings.TrimPrefix(href, "../")))
if !HyphaExists(hyphaName) {
class = "wikilink_new"
}
href = path.Join("/page", hyphaName)
case strings.HasPrefix(href, "/"):
case strings.ContainsRune(href, ':'):
class = "wikilink_external"
default:
href = path.Join("/page", href)
}
return href, strings.TrimSpace(text), class
}
func lex(name, content string) (ast []Line) {
var state = GemLexerState{name: name}
for _, line := range append(strings.Split(content, "\n"), "") {
geminiLineToAST(line, &state, &ast)
}
return ast
}
// Lex `line` in gemtext and save it to `ast` using `state`.
func geminiLineToAST(line string, state *GemLexerState, ast *[]Line) {
addLine := func(text interface{}) {
*ast = append(*ast, Line{id: state.id, contents: text})
}
if "" == strings.TrimSpace(line) {
if state.where == "list" {
state.where = ""
addLine(state.buf + "</ul>")
}
return
}
startsWith := func(token string) bool {
return strings.HasPrefix(line, token)
}
// Beware! Usage of goto. Some may say it is considered evil but in this case it helped to make a better-structured code.
switch state.where {
case "pre":
goto preformattedState
case "list":
goto listState
default:
goto normalState
}
preformattedState:
switch {
case startsWith("```"):
state.where = ""
state.buf = strings.TrimSuffix(state.buf, "\n")
addLine(state.buf + "</code></pre>")
state.buf = ""
default:
state.buf += html.EscapeString(line) + "\n"
}
return
listState:
switch {
case startsWith("*"):
state.buf += fmt.Sprintf("\t<li>%s</li>\n", remover("*")(line))
case startsWith("```"):
state.where = "pre"
addLine(state.buf + "</ul>")
state.id++
state.buf = fmt.Sprintf("<pre id='%d' alt='%s' class='codeblock'><code>", state.id, strings.TrimPrefix(line, "```"))
default:
state.where = ""
addLine(state.buf + "</ul>")
goto normalState
}
return
normalState:
state.id++
switch {
case startsWith("```"):
state.where = "pre"
state.buf = fmt.Sprintf("<pre id='%d' alt='%s' class='codeblock'><code>", state.id, strings.TrimPrefix(line, "```"))
case startsWith("*"):
state.where = "list"
state.buf = fmt.Sprintf("<ul id='%d'>\n", state.id)
goto listState
case startsWith("###"):
addLine(fmt.Sprintf(
"<h3 id='%d'>%s</h3>", state.id, removeHeadingOctothorps(line)))
case startsWith("##"):
addLine(fmt.Sprintf(
"<h2 id='%d'>%s</h2>", state.id, removeHeadingOctothorps(line)))
case startsWith("#"):
addLine(fmt.Sprintf(
"<h1 id='%d'>%s</h1>", state.id, removeHeadingOctothorps(line)))
case startsWith(">"):
addLine(fmt.Sprintf(
"<blockquote id='%d'>%s</blockquote>", state.id, remover(">")(line)))
case startsWith("=>"):
source, content, class := wikilink(line, state)
addLine(fmt.Sprintf(
`<p><a id='%d' class='%s' href="%s">%s</a></p>`, state.id, class, source, content))
case startsWith("<="):
addLine(parseTransclusion(line, state.name))
default:
addLine(fmt.Sprintf("<p id='%d'>%s</p>", state.id, line))
}
}