mautrix-go/format/mdext/shortstrike.go

77 lines
2.2 KiB
Go

// Copyright (c) 2024 Tulir Asokan
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
package mdext
import (
"github.com/yuin/goldmark"
gast "github.com/yuin/goldmark/ast"
"github.com/yuin/goldmark/extension"
"github.com/yuin/goldmark/extension/ast"
"github.com/yuin/goldmark/parser"
"github.com/yuin/goldmark/renderer"
"github.com/yuin/goldmark/text"
"github.com/yuin/goldmark/util"
)
var ShortStrike goldmark.Extender = &shortStrikeExtender{length: 1}
var LongStrike goldmark.Extender = &shortStrikeExtender{length: 2}
type shortStrikeExtender struct {
length int
}
func (s *shortStrikeExtender) Extend(m goldmark.Markdown) {
m.Parser().AddOptions(parser.WithInlineParsers(
util.Prioritized(&strikethroughParser{length: s.length}, 500),
))
m.Renderer().AddOptions(renderer.WithNodeRenderers(
util.Prioritized(extension.NewStrikethroughHTMLRenderer(), 500),
))
}
type strikethroughDelimiterProcessor struct{}
func (p *strikethroughDelimiterProcessor) IsDelimiter(b byte) bool {
return b == '~'
}
func (p *strikethroughDelimiterProcessor) CanOpenCloser(opener, closer *parser.Delimiter) bool {
return opener.Char == closer.Char
}
func (p *strikethroughDelimiterProcessor) OnMatch(consumes int) gast.Node {
return ast.NewStrikethrough()
}
var defaultStrikethroughDelimiterProcessor = &strikethroughDelimiterProcessor{}
type strikethroughParser struct {
length int
}
func (s *strikethroughParser) Trigger() []byte {
return []byte{'~'}
}
func (s *strikethroughParser) Parse(parent gast.Node, block text.Reader, pc parser.Context) gast.Node {
before := block.PrecendingCharacter()
line, segment := block.PeekLine()
node := parser.ScanDelimiter(line, before, 1, defaultStrikethroughDelimiterProcessor)
if node == nil || node.OriginalLength != s.length || before == '~' {
return nil
}
node.Segment = segment.WithStop(segment.Start + node.OriginalLength)
block.Advance(node.OriginalLength)
pc.PushDelimiter(node)
return node
}
func (s *strikethroughParser) CloseBlock(parent gast.Node, pc parser.Context) {
// nothing to do
}